4. Basic Hepatology Part I Muhammad Diasty
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1 CCLLIINNIICCAALL AASSSSEESSSSMMEENNTT OOFF LLIIVVEERR DDIISSEEAASSEE
Assessment of liver disease encompasses: (table 1)
History
Clinical findings
Biochemical tests
Liver histology
Table 1
Clinical features of cirrhosis and liver cell failure
1 General features
Fatigue
Aanorexia
Malaise
Weight loss
Muscle wasting
Fever
2 Gastrointestinal
Parotid enlargement
Diarrhea
cholelithiasis
Gastrointestinal bleeding
esophageal/gastric/duodenal/rectal/stomal varices
portal hypertensive gastropathy/colopathy
3 Hematologic
Anemia
folate deficiency
spur cell anemia (hemolytic anemia seen in severe
alcoholic liver disease)
splenomegaly with resulting pancytopenia
Thrombocytopenia
Leukopenia
Impaired coagulation
Disseminated intravascular coagulation
Hemosiderosis
4 Pulmonary
Decreased oxygen saturation
Altered ventilation‐perfusion relationships
Portopulmonary hypertension
Hyperventilation
Reduced pulmonary diffusion capacity
Hepatic hydrothorax
Hepatopulmonary syndrome
5 Musculoskeletal
Reduction in lean muscle mass
Hypertrophic osteoarthropathy: synovitis, clubbing,
and periostitis
Hepatic osteodystrophy
Muscle cramps
Umbilical herniation
6 Cardiac
Hyperdynamic circulation
Cirrhotic cardiomyopathy
7 Endocrinologic
Hypogonadism
males: loss of libido, testicular atrophy, impotence,
decreased amounts of testosterone
females: infertility, dysmenorrhea, loss of secondary
sexual characteristics
Feminization=acquisition of estrogen‐induced
characteristics:
spider telangiectases
palmar erythema
gynecomastia
changes in body hair patterns
Diabetes
8 Neurologic
Hepatic encephalopathy
Peripheral neuropathy
9 Renal
Secondary hyperaldosteronism – leads to sodium
and water retention
Renal tubular acidosis (more frequent in alcoholic
cirrhosis, Wilson disease, and primary biliary
cirrhosis)
Hepatorenal syndrome
10 Dermatologic
Spider telangiectases
Palmar erythema
Nail changes:
azure lunules (Wilson disease)
Muehrcke’s nails: paired horizontal white bands
separated by normal color
Terry’s nails: white appearance to the proximal two-
thirds of the nail plate
Dupuytren’s contractures
Clubbing
Jaundice
Paper money skin
Caput medusae
5. Basic Hepatology Part I Muhammad Diasty
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2 IINNVVEESSTTIIGGAATTIINNGG AANNDD IIMMAAGGIINNGG TTHHEE LLIIVVEERR AANNDD BBIILLIIAARRYY TTRRAACCTT
Investigations can be divided into:
Laboratory Investigations
Hepatic Imaging
Liver biopsy
Laboratory Investigations
Blood tests
Biochemical liver function tests: See table 2
Most laboratories produce a panel of assays including bilirubin, alkaline phosphatase (AP),
alanine aminotransferase (ALT), aspartate aminotransferase (AST) and γ-glutamyltransferase (γGT).
Although these are usually called ‘liver function tests’, it is important to realize that there is
little or no correlation between abnormalities in these biochemical values and liver function
– they are nonspecific indicators that there may be liver or biliary disease.
Tests of synthetic function
The liver produces and secretes a large number of proteins. Among these, albumin,
coagulation factors, and lipoproteins can be routinely measured and reflect the synthetic
capacity of the liver.
Albumin
Albumin levels reflect not only hepatic synthetic capacity, but also nutritional and catabolic
status and osmotic pressure.
Other causes of hypoalbuminemia:
nephrotic syndrome
protein-losing enteropathy
malnutrition
extensive burns
In cirrhotic patients, plasma albumin levels correlate with prognosis.
Prothrombin Time and Coagulation Factor Levels
The liver plays a central role in the maintenance of normal hemostasis. It synthesizes the
coagulation factors I, II, V, VII, IX, and X (15/1972), which are involved in the extrinsic
coagulation pathway and can be assessed by measurement of the prothrombin time.
Factors II, VII, IX, and X (1972) are dependent on vitamin K for γ-carboxylation.
Notably, factor VIII is not made in the liver and can be used to distinguish DIC from liver
related abnormalities in bleeding parameters, though this is rarely a clinical dilemma.
More importantly, since factor V production is not dependent on vitamin K presence,
measurement can be used to distinguish vitamin K deficiency as a cause of prolonged PT
from liver disease-related causes.
Prolongation of the prothrombin time has been found to be more predictive of prognosis in
patients with chronic liver disease than are serum aminotransferase, bilirubin, and albumin levels.
Plasma Lipids and Lipoproteins
The liver has a central role in the production and metabolism of plasma lipoproteins.
The liver is the major source of all lipoproteins, except chylomicrons, and the hepatic
enzymes lecithin-cholesterol acyltransferase (LCAT) and hepatic lipase play major roles in
modifying the composition of lipoproteins.
In acute hepatocellular injury: Increased plasma levels of triglycerides and decreased levels of
cholesterol esters. In addition, LDL triglyceride levels are often increased.
Patients with intrahepatic or extrahepatic cholestasis often have highly elevated plasma
cholesterol and phospholipid levels.
6. Table 2
Enzymes Reflecting Liver Injury
Lab Test Physiologic Function Source
Commonly Associated
Liver Abnormalities
Of Note Pitfalls
AST
Catalyzes transfer of aminogroup from aspartic
acid to ketoglutaric acid to produce oxaloacetic
acid
Liver, heart, kidney, pancreas, brain,
RBC, WBC
Viral hepatitis, alcohol liver injury,
ischemic hepatic injury, drug induced
hepatitis, fatty liver disease, Wilson’s
disease, celiac disease, α-1-
Antitrypsin deficiency
AST/ALT ratio > 2 typically due to
alcohol injury.
AST/ALT > 1 also seen in
cirrhosis.
ALT rarely > 300 U/L in chronic
conditions.
May be normal viral hepatitis or with
advancing fibrosis.
Falsely low with dialysis.
Poor correlation with degree of liver
necrosis in acute setting.ALT
Catalyzes transfer of amino group from alanine
acid to ketoglutaric acid to ketoglutaric produce
pyruvic acid
Liver
LDH
Catalyzes interconversion of lactate and pyruvate Heart, liver, kidney, muscle, brain,
blood cells, lungs, necrotic
conditions, infiltrative disorders,
hemolysis, muscle injury,
malignancies
Several isoenzymes which can be measured.
Poor specificity for liver disease, and not useful overall.
Liver Tests Reflecting Cholestasis and Biliary Tract Disorders
Bilirubin,
conjugated
Bilirubin glucoronide, results from conjugation of
bilirubin in the liver.
Water soluble.
Liver Liver necrosis, PBC/PSC, cirrhosis,
intrahepatic cholestasis due to drugs
or genetic abnormality, sepsis, bilary
tract obstruction
Prognostically useful in alcohol
liver disease, PSC, PBC;
Renally excreted, so rarely > 30
mg/dL with normal renal
function
Value of conjugated bilirubin may be
overestimated with diazo method of
measurement;
Often elevated in sepsis or
postoperative situations in setting of
no liver disease
Bilirubin,
unconjugated
Organic anion from hemoglobin degradation.
Lipid soluble
RBC breakdown
Defects in hepatic conjugation or
uptake
Hemolysis
Physiologic jaundice of newborn
Inherited defects of bilirubin uptake
Sustained hemolysis will not
result in value > 5 mg/dL in
setting of normal liver function
Alkaline
phosphatase
Group of glycoprotein isoenzymes that catalyze
hydrolysis of phosphate esters
Liver, bone, kidney, intestines,
placenta, cancers, WBCs
Cholestatic liver diseases
Obstruction of bile flow
Infiltrative disorders of liver
Malignancies
Coded by four genes
Immunologically distinct
Found on plasma membranes
Elevations due primarily to
increased synthesis in
obstructive liver disease, not
impaired excretion in bile
Multiple sources; Exact physiologic
function not clear; Degree of
elevation often does not correlate
with clinical finding
GGT
Catalyzes transfer of γ-glutamyl groups of peptides
to other amino acids
Liver, spleen, kidney, brain, heart,
lung, pancreas, seminal vesicles
Cholestatic liver disease, alcohol
injury, biliary tract disease
Membrane associated and found
in biliary tree; Catalyzes
metabolism of glutathione
conjugates with some
xenobiotics
Found in many tissues
Sometimes not elevated with alkaline
phosphatase in liver disease
Elevated with alcohol use in some
patients and with certain medications
5´NT
Catalyzes hydrolysis of nucleotides by releasing
phosphate from pentose ring
Liver, intestines, brain, heart, vascular
tissue, pancreas
Cholestatic disease where alkaline
phosphatase is elevated
Physiologic significance not
known; Although found in
several tissues, only released
from plasma membranes of
hepatobiliary tissue with injury
Not readily available through all
laboratories
LDH = lactate dehydrogenase; GGT = γ-glutamyl transpeptidases; 5´NT = 5´ nucleotidase; PBC = primary biliary cirrhosis; PSC = primary sclerosing cholangitis.
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Autoantibodies
Antinuclear antibodies (ANA), smooth muscle antibodies (SMA) and antimitochondrial
antibodies (AMA) are helpful in identifying an autoimmune cause of unexplained chronic
liver disease.
Fractionation of antimitochondrial antibodies and detection of other antibodies (e.g.
antiliver–kidney microsomal antibodies) may be helpful in difficult cases.
Hepatitis serology
Tests for hepatitis A, B and C are mandatory in unexplained liver disease; these tests are now
sufficiently refined to distinguish present or continuing infection from past infection.
Screening tests are:
• hepatitis A IgM antibodies
• hepatitis B surface antigen
• antibodies to hepatitis C virus by ELIZA.
More complex tests may be required to interpret positive tests.
Iron and copper studies
In unexplained liver disease, it is important to exclude haemochromatosis and Wilson’s
disease.
Serum ferritin and iron saturation are raised in haemochromatosis.
Serum ceruloplasmin is decreased in Wilson’s disease; the diagnosis is unlikely when the level
is normal.
Markers of alcohol misuse
Elevation of γGT in isolation does not necessarily indicate liver disease and often results from
enzyme induction, particularly by alcohol or drugs (e.g. phenytoin).
Other useful markers of alcohol misuse are carbohydrate deficient transferrin and
mitochondrial AST. In at least 50% of individuals misusing alcohol, there is generalized
enlargement of RBCs (raised MCV).
Tumour markers
α-fetoprotein (AFP): the principal tumour marker of clinical use in liver disease. AFP is
elevated in 80% of patients with primary liver cell cancer and, in combination with hepatic
ultrasound, can be used to screen patients with cirrhosis.
Modest elevations of AFP (up to 10 times normal) may be seen in active inflammation or
regeneration, but progressively rising AFP is of ominous significance. Hundredfold elevations
of AFP are seen only in primary HCC and germ cell tumours.
Carcinoembryonic antigen (CEA): has a place in the follow-up of patients with treated
colon cancer, in whom rising CEA levels may indicate the presence of metastases in the liver.
Dynamic tests of liver function
These tests have a role in research and in assessing response to treatment. They depend on
the clearance of an administered substance from the blood, test substances include:
• bromosulphthalein
• indocyanine green
• antipyrine
• aminopyrine
• lignocaine
• galactose.
There is a complex interaction between drug delivery to the liver by alterations in liver blood
flow or shunting, altered uptake by hepatocytes, disordered metabolism and abnormalities
of biliary excretion.
Clearance of drugs with high first-pass hepatic extraction (e.g. lignocaine, indocyanine green) reflects
liver blood flow.
Clearance of substances with very low first-pass extraction (e.g. antipyrine) is relatively independent
of liver blood flow and is generally a better test of hepatocyte function.
8. Basic Hepatology Part I Muhammad Diasty
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Hepatic Imaging
Plain radiography
Plain abdominal x‐rays are typically not helpful in the evaluation of liver disease.
Incidental calcifications may suggest gallstone disease, echinococcal infection or TB.
An elevated right hemidiaphragm can result from a pyogenic liver abscess or advanced HCC.
A right-sided pleural effusion in a patient with ascites suggests hepatic hydrothorax.
Ultrasound: The usual first line imaging test, characterized by:
Ultrasound is noninvasive, readily available, fairly inexpensive, and the most common initial
imaging modality for liver disease.
Ultrasound can also detect parenchymal liver disease, hepatic mass lesions, and, with Doppler
imaging, vascular occlusion or compromise.
Ultrasound is often superior to other imaging techniques in characterizing hepatic cysts.
Ultrasound cannot generally differentiate benign from malignant liver lesions.
Moderate to marked steatosis of the liver is often seen on ultrasound as increased echogenicity,
with a characteristically bright liver, often with hepatomegaly.
With realtime imaging, ultrasound is used to guide biopsies and drain abscesses.
CT
More accurate than ultrasound in defining hepatic anatomy.
CT is commonly used in the evaluation of hepatic mass lesions (especially spiral CT) and in some
patients with abnormal LFTs.
Oral contrast is required to visualize the intestinal lumen, and intravenous contrast is often
administered, especially for imaging hepatic mass lesions and vascular abnormalities in the liver.
CT cholangiography (following infusion of intravenous cholangiographic contrast) can show the
biliary tree elegantly, providing liver function remains near normal. The greater toxicity of these agents
compared with ‘conventional’ iodinated contrast has limited the application of this test.
MRI is expanding rapidly, but its precise role in liver investigation is unclear.
The current position can be summarized as follows:
Unenhanced MRI is comparable to enhanced spiral CT and better than ultrasonography in the
detection of liver lesions.
The role of MRI in evaluation of the biliary tree (magnetic resonance cholangiography {MRCP}) is
expanding. In combination with endoscopic ultrasound, these tests have largely replaced ‘diagnostic’
ERCP by producing excellent non- or minimally-invasive images of bile ducts.
MRI shows considerable promise as a ‘one-stop’ investigation for the liver, providing superb
anatomical detail and good lesion detection and characterization, and enabling assessment of the
biliary tree, portal and hepatic arterial systems and related organs such as the pancreas and spleen.
Isotope scanning of the hepatobiliary system
The use of radionuclides in liver imaging has declined with increasing availability of other
imaging techniques. Present uses include the following.
Technetium-labelled RBCs are used to assess liver haemangioma.
A combination of Tc-colloid and gadolinium-67 is used to differentiate HCC from regenerative
nodules of cirrhosis.
Positron emission tomography (PET), using labelled somatostatin analogues to evaluate
neuroendocrine tumours, has been described recently.
99mTc-iminodiacetic acid derivatives used to evaluate cystic duct patency have a sensitivity and
specificity of more than 95%.
They have the advantage that they can be used at higher levels of bilirubin than iodinated
cholecystographic media.
9. Basic Hepatology Part I Muhammad Diasty
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Liver biopsy
Indications
1) Assessment of chronic liver disease
2) Investigation of acute hepatic dysfunction
3) Targeted biopsy of focal lesions
4) Investigation of systemic disease e.g. sarcoidosis, amyloidosis, lymphoma, tuberculosis
5) Assessment for liver transplantation
Contraindications
There are no absolute contraindications to liver biopsy; the risk:benefit ratio must be
assessed in each patient. Particular concerns are:
1) Coagulopathy (the risk of bleeding is greater)
2) Patient inability to cooperate with the breathing manoeuvres needed for percutaneous
biopsy (e.g. learning disability, retardation, impaired consciousness, respiratory disease)
3) Large amounts of ascites
4) Suspected extrahepatic obstruction (biliary peritonitis seldom follows biopsy in this
situation provided the gallbladder is not punctured).
Common clinical scenarios
Asymptomatic abnormalities of biochemical liver function tests
Patients usually present through health screening or the investigation of non-liver-related symptoms.
• Isolated elevation of AP when other enzymes (including γGT) are normal suggests coincidental bone disease
(often Paget’s disease).
• Elevation of AP and γGT usually indicates significant cholestasis or hepatic infiltration warranting full
investigation.
• Isolated elevation of γGT is likely to result from enzyme induction and does not indicate liver damage. The most
common inducer is alcohol, and correlative evidence may be obtained from raised MCV or carbohydrate-deficient
transferrin. Liver biopsy is not indicated.
• Isolated elevation of ALT or AST warrants exclusion of chronic viral hepatitis, metal overload and autoimmune
chronic hepatitis by appropriate blood tests.
• Ultrasound should be performed; the most common finding, when diagnostic blood tests are negative, is
increased parenchymal echogenicity indicating fatty liver. In the absence of evidence of alcohol misuse or any
other aetiological factor for liver disease, liver histology seldom adds information in patients with mild isolated
elevation of ALT or AST below twice normal. Liver biopsy is not recommended.
• If drug tests are arranged before starting a potentially hepatotoxic drug such as a statin, minor abnormalities are
an indication to withhold medication and repeat the tests a few weeks later. If the drug is then started, the
biochemistry should be checked 1–2 months later.
Assessment of established cirrhosis
Patients may present for the first time with a complication of cirrhosis such as bleeding varices or ascites.
Investigation should be aimed at:
• determining the cause – hepatitis serology, autoantibodies, metal studies and α1-antitrypsin
• assessing severity – clotting studies and albumin
• excluding primary HCC – AFP and ultrasound, supplemented by CT or MRI in patients with a suspicious
abnormality.
Imaging also has a role in confirming the presence of ascites and splenomegaly and in assessing vascular
complications such as the extent of collaterals (from portal hypertension) and the patency of the portal and hepatic
veins.
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3 HHIISSTTOOLLOOGGIICCAALL AASSSSEESSSSMMEENNTT OOFF TTHHEE LLIIVVEERR
Histopathological assessments continue to play an important role in diagnosis and
management of patients with liver disease:
For some conditions (e.g. liver allograft rejection), histopathology is still regarded as the diagnostic gold
standard.
In other circumstances, when a diagnosis has been made by other investigations, evaluation of morphological
changes may provide additional information that is useful for clinical management – examples include grading
of inflammatory activity and staging of fibrosis in chronic viral hepatitis and the distinction between simple
steatosis and steatohepatitis in alcoholic and non-alcoholic fatty liver disease.
In addition, liver biopsy may reveal abnormalities (e.g. iron overload, α1- antitrypsin globules) that have not
been detected by previous investigations.
Interpretation of liver biopsy
The main features below should be included in the evaluation of all liver biopsies in which a
diffuse liver injury is suspected.
Liver architecture – to determine whether normal vascular relationships between portal
tracts and hepatic venules are retained.
Portal tracts are the site at which circulating lymphoid cells first gain access to the liver.
Portal inflammation is common in many liver diseases, but is particularly characteristic of
chronic viral or autoimmune hepatitis.
The nature of the inflammatory cells may provide a clue to the liver disease (e.g. numerous plasma
cells in autoimmune hepatitis, granulomata in primary biliary cirrhosis, eosinophils in drug reactions).
The term ‘interface hepatitis’ is now preferred to ‘piecemeal necrosis’ to describe the spillover of
inflammatory cells from portal areas into adjacent liver parenchyma with presumed damage to
periportal hepatocytes. This lesion is thought to be important in the pathogenesis of periportal fibrosis,
which occurs in many chronic liver diseases.
Bile ducts are important targets for injury in many immune-mediated diseases and some
non-immunological disorders.
The term ‘vanishing bile duct syndrome’ is used to describe cases in which there is substantial bile
duct loss (usually defined as ducts missing from >50% of portal tracts).
Assessment of portal vessels (hepatic arterioles and portal venules) has a limited use in
routine liver biopsy diagnosis.
Arterial lesions are seldom seen in systemic vasculitides (e.g. polyarteritis nodosa).
Obliteration of portal venules is seen in non-cirrhotic portal hypertension.
Bile ductular reaction is commonly seen in many forms of liver injury, but is particularly
prominent in chronic cholestatic liver diseases, where it may lead to the development of
progressive periportal fibrosis.
Liver parenchyma – important lesions in the liver parenchyma include:
inflammatory infiltration
hepatocellular degenerative changes (e.g. fatty change, bile stasis, ballooning, Mallory’s hyalin)
liver cell death by necrosis or apoptosis.
Many conditions involving the liver parenchyma tend to have a zonal distribution, particularly
involving regions around terminal hepatic venules (acinar zone 3).
Non-parenchymal cells in hepatic sinusoids (Kupffer cells, hepatic stellate cells and
sinusoidal endothelial cells).
Abnormal Kupffer cells are found in some storage diseases (e.g. Gaucher’s disease) and in certain
intracellular infections (e.g. leishmaniasis).
Enlarged Kupffer cells laden with ceroid ‘wear and tear’ pigment (or sometimes haemosiderin) are
commonly present as a nonspecific manifestation of recent hepatocyte injury.
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Hepatic veins
Occlusion of terminal hepatic venules is characteristically seen in so-called veno-occlusive
disease (VOD) of the liver.
The primary site of injury in hepatic VOD is now thought to be the endothelium lining hepatic
sinusoids (‘sinusoidal obstruction syndrome’), with occlusion of hepatic venules occurring as
a secondary event.
Veno-occlusive lesions can also occur as a secondary phenomenon in other causes of venous
outflow obstruction (e.g. Budd–Chiari syndrome, constrictive pericarditis) and, to a lesser
degree, in many forms of chronic liver disease (e.g. alcoholic cirrhosis).
Special stains used in routine liver biopsy assessment and their diagnostic applications are
shown in table 3.
Table 3
Special stains used in routine histological assessment of liver biopsies
Stain Material demonstrated Distribution in normal liver Changes in liver disease
Reticulin Type III collagen fibres Portal tracts, hepatic sinusoids Collapse of reticulin framework in
areas of recent liver cell necrosis
Thickening of cell plates in areas
of nodular regeneration
Haematoxylin Van
Gieson
Type I collagen fibres Portal tracts, walls of hepatic
vessels
Increased in hepatic fibrosis
Orcein Hepatitis B surface antigen
Copper-associated protein
Elastic fibres
Portal tracts
Walls of hepatic vessels
Present in some patients with
chronic hepatitis B virus infection
Present in chronic cholestasis
Found in long-standing
fibrosis/cirrhosis
Periodic acid-Schiff Glycogen Hepatocytes
Periodic acid-Schiff
diastase
Mucin
α1-antitrypsin globules
Bile ducts Present in α1-antitrypsin
deficiency
Perls’ reaction Haemosiderin Increased in haemosiderosis/
haemochromatosis
Immunohistochemical studies are increasingly used as an adjunct to conventional
histological diagnosis. Substances that may be detected immunohistochemically in tissue
sections include:
viral antigens (e.g. HBsAG, HBcAg, HDV, CMV, EBV)
Mallory’s hyaline
alpha-1-antitrypsin
bile duct cytokeratins such as cytokeratin 7 (to detect residual biliary epithelial cells and highlight foci of
ductular reaction in vanishing bile duct diseases).
Immunohistochemical stains also have an important role in the differential diagnosis of
neoplastic lesions in the liver.
NB: Problems with interpretation of liver biopsy
Sampling variation
The average liver biopsy samples only about 1/100,000 of the whole liver. Much useful information can still be
obtained, because many disease processes affect the liver fairly uniformly.
Lesions with a reasonably uniform distribution in liver include:
hepatocyte necrosis in toxic liver injury (e.g. paracetamol poisoning)
steatosis in fatty liver disease (alcoholic and non-alcoholic)
inflammation in many cases of acute and chronic hepatitis (viral and autoimmune).
Clinicopathological correlation in the interpretation of liver biopsy findings
Many liver diseases have overlapping histological features, and small needle biopsies may not contain the
pathognomonic features that allow definite diagnosis.
Request forms for liver biopsies should always be accompanied by a clinical history, including the results of any
relevant biochemical, serological and radiological investigations.
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Histological grading and staging in chronic liver disease
Pathological grading and staging has been applied to the assessment of chronic liver diseases,
including chronic viral hepatitis and fatty liver disease.
The histological grade is thought to provide an indication of ongoing damage to the liver, which is
potentially treatable.
Features that can be graded include inflammation in chronic viral hepatitis, and steatosis and
hepatocyte ballooning in fatty liver disease.
The fibrosis stage is a measure of progressive liver injury, which is less likely to be reversible.
Various attempts have been made to convert subjective assessments of inflammatory activity
and fibrosis into numerical scores.
A number of non-invasive methods have been developed for assessing the pathological
changes that occur in liver disease, particularly hepatic fibrosis. Non-invasive methods for
assessing liver fibrosis include serological markers and various imaging techniques.
However, at present much of the information provided by non-invasive techniques is best
regarded as an adjunct to liver biopsy rather than a replacement for it.
Grading and Staging
There are a couple of ways to read a liver biopsy. The most common scoring methods are
known as the Metavir and the Knodell Score.
Metavir
The Metavir scoring system was set up just for patients with hepatitis C. The scoring uses both
a grade and a stage system.
The grade tells you about the activity or amount of swelling and irritation (inflammation).
The stage tells you the amount of fibrosis or scarring.
The grade is given a number based on the amount of inflammation. This is usually scored from
0-4. A 0 is no activity and 3 or 4 is severe activity.
The amount of inflammation is important because it may lead to eventual scarring or damage.
The fibrosis score is also assigned a number from 0-4:
0 = no scarring
1 = minimal scarring
2 = scarring has occurred and is outside the areas of the liver including blood vessels
3 = bridging fibrosis (the fibrosis is spreading and connecting to other areas that contain fibrosis)
4 = cirrhosis or advanced scarring of the liver
Knodell
The Knodell score or HAI (histologic activity index) is also commonly used to stage liver
disease. It is a bit more complex a process than using the Metavir score. But some experts
believe that it is a better at finding how much liver inflammation and damage are present.
It has four different numbers that make up a single score.
The addition of these numbers tells the amount of inflammation in the liver:
0
1-4
5-8
9-12
13-18
= no inflammation
= minimal inflammation
= mild inflammation
= moderate inflammation
= marked inflammation
The fourth part of the score deals with the amount of scarring in the liver and is scored from
0 (no scarring) to 4 (extensive scarring or cirrhosis).
13. Basic Hepatology Part I Muhammad Diasty
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4 AACCUUTTEE LLIIVVEERR FFAAIILLUURREE
Definition
Acute liver failure (ALF) is a condition characterized by jaundice, coagulopathy and
encephalopathy in a patient with previously normal liver function.
Fulminant hepatic failure
The term was introduced in 1970 for patients who met the following criteria:
• Acute onset of liver disease with coagulopathy
• Development of HE within 8 weeks of the onset of the illness
• No prior evidence of liver disease
Subfulminant hepatic failure
This term describes a further subgroup of patients with acute liver failure characterized by
the later development of HE, i.e., 2 weeks (or 8 weeks) to 3 months (or 6 months) after the
onset of jaundice (or illness).
New terminology
• hyperacute liver failure (7 days between onset of jaundice and encephalopathy)
• acute liver failure (8–28 days)
• subacute liver failure (5–12 weeks).
Aetiology: (Table 4)
Table 4
Causes of acute liver failure
• Infection (hepatitis A, B, C, D, E, cytomegalovirus, herpes simplex virus, Epstein–Barr virus, varicella)
• Drugs (paracetamol (acetaminophen), isoniazid, monoamine oxidase inhibitors (MAOIs), non‐steroidal anti‐
inflammatory drugs (NSAIDs), halothane, Ecstasy, gold, phenytoin)
• Metabolic (Wilson’s disease, Reye’s syndrome)
• Cardiovascular (Budd–Chiari syndrome, ischaemic hepatitis)
• Miscellaneous (acute fatty liver of pregnancy, lymphoma, amanita phalloides, herbal medicines)
Pathology
There is centrilobular necrosis of hepatocytes with activation of macrophages and liberation
of cytokines, specifically tumour necrosis factor and interleukins 1 and 6.
Clinical presentation
ALF usually presents with malaise, nausea and jaundice.
The interval between the onset of jaundice and the onset of encephalopathy depends on the
aetiology and is used to classify ALF (hyperacute, acute and subacute)
This classification has implications for the prognosis and incidence of cerebral oedema, which
is more common in hyperacute failure.
As liver failure progresses, encephalopathy becomes the characteristic feature.
Following massive ingestion of acetaminophen, a characteristic clinical picture evolves:
Initial phase (0-24 h)
Anorexia, nausea and vomiting
Latent phase (24-48 h)
Resolution of GIT symptoms
Elevated serum aminotransferase levels
Overt hepatocellular necrosis phase (> 48 h)
Progressive abnormalities of liver function tests, jaundice, encephalopathy
Renal failure may occur
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Diagnosis and investigations
There is no specific diagnostic test for ALF
Specific tests to identify the cause may include:
• viral serology for the hepatitis viruses
• plasma caeruloplasmin and 24-hour urinary copper to diagnose Wilson’s disease
• hepatic ultrasound to demonstrate hepatic vascular occlusion in Budd–Chiari syndrome.
There will be elevation of:
• serum bilirubin (a level over 18 mg/dl implies severe disease)
• plasma AST and ALT reflecting hepatocellular damage
• prothrombin time (PT) (used as an indicator of the severity of the disease).
Other common abnormalities are:
Hypoglycaemia, hyponatraemia, hypomagnesaemia, respiratory alkalosis and metabolic
acidosis.
Complications (Table 5)
Table 5
Complications of Acute Liver Failure
Complications Features Management
Encephalopathy The hallmark of FHF.
Once grade 3 or 4 develops, the
frequency of multiorgan failure and
death is high
See hepatic encephalopathy
Cerebral oedema Develops in 80% of patients with Grade
IV encephalopathy and is the cause of
death in about 30–50% of patients
with ALF.
It is the result of the high level of
ammonia, which leads to an increase
in the synthesis of intracellular
cerebral glutamine. This increases
osmotic pressure in astrocytes,
resulting in cerebral oedema.
General measures
decrease tactile stimulation
tilt up the head 20o
to improve cerebral
perfusion pressure
avoid hypotension, hypoxia and hypercapnea
Specific measures
mannitol (0.4 g/kg iv bolus) every hour until ICP
improves
hyperventilation (in stage 3 or 4 HE)
corticosteroids are ineffective
Renal failure Renal failure occurs in 70% of patients
after paracetamol (acetaminophen)
overdose due to its nephrotoxic effect.
Sepsis and hypovolaemia also
contribute to renal failure.
Replace fluids if the pt is hypovolaemic
Consider dopamine at a dose of 2‐4 μg/kg/h
and hemodialysis or hemofilteration if the
pt is being considered for transplantation.
Coagulopathy A major feature of ALF, because the
liver synthesizes all the coagulation
factors apart from factor VIII.
Sepsis, reduced protein C and
antithrombin III levels contribute to
low‐ grade disseminated intravascular
coagulation (DIC).
The PT is a good measure of the severity of
the disease and should not be corrected
unless the patient is actively bleeding.
Thrombocytopenia should be corrected if the
platelet count falls below 50 x 109
/litre.
Sepsis Infection is common as a result of
neutrophil and Küpffer cell dysfunction
and sepsis is the cause of death in 11% of
cases.
Bacterial infections with Gram‐positive
organisms are seen in the first week and
fungal infections after 2 weeks.
Prophylactic fluconazole, 100 mg/day, should
be started.
Metabolic
disorders
Hypoglycaemia, hyponatraemia, hypomagnesaemia, respiratory alkalosis and metabolic
acidosis.
15. Basic Hepatology Part I Muhammad Diasty
12
Management
The main aims of treatment are the control of cerebral oedema and supportive management
of multiple organ failure until hepatic regeneration occurs.
Sepsis and cerebral oedema are the main causes of death.
General management of FHF:
Full hemodynamic monitoring (arterial line, pulmonary artery catheter)
Endotracheal intubation and intracranial pressure monitoring for stage 3 HE
Parenteral glucose (DXW 10 or 20%) to prevent hypoglycaemia
Correct electrolytes and acid-base disorders
Parenteral H2 blockers to reduce chance of GIT bleeding
Mannitol to treat elevated ICP
Treatment of complications
If acetaminophen is suspected, treat as follows:
N-acetylcysteine (may be beneficial in the management of ALF even if paracetamol is not the
cause, it has been shown to increase cardiac output and oxygen delivery) and is given as a
loading dose of 300 mg/kg followed by an infusion of 150 mg/kg/hour.
Consider liver transplantation
There has been considerable research into the development of an artificial liver. Trials of
systems using extracorporeal perfusion of blood through columns of hepatocytes, or dialysis
against an albumin-coated membrane have been undertaken, but most studies are small and
experimental (see part II).
Table 6
King’s College Hospital criteria for liver transplantation in acute liver failure
Acetaminophen Toxicity All Other Causes
pH <7.3 (irrespective of grade of encephalopathy)
or
Prothrombin time >50 seconds and serum creatinine
>3.4 mg/dL (300 μmol/L) in
Patients with grade III or IV encephalopathy
Prothrombin time >50 seconds (irrespective of grade
encephalopathy)
or
Any three of the following variables (irrespective of
grade of encephalopathy):
Age <10 years or >40 years
Liver failure due to halothane or other drug
idiosyncrasy or idiopathic hepatitis
Duration of jaundice prior to encephalopathy >7 d
Prothrombin time >25 seconds
Serum bilirubin >17.5 mg/dL (300 μmol/L)
Prognosis
Overall survival with medical treatment is 10–40%.
The prognosis depends on the aetiology and is best after paracetamol overdose and hepatitis
A, and worst for non-A, non-B hepatitis and idiosyncratic drug reactions.
The time to the onset of encephalopathy also affects prognosis, hyperacute failure has a
35% survival and subacute failure has a 15% survival.
The outcome from transplantation for ALF is improving and is now 65–75%.
NB:
According to its strict definition, the diagnosis of ALF requires liver failure in a patient with a previously healthy organ.
However, some patients present with ALF superimposed on unrecognized chronic liver disease. Although purists do
not consider this to represent true ALF, patients with acute decompensation of previously subclinical liver disease
should be considered under the umbrella of ALF for the purposes of management.
16. Basic Hepatology Part I Muhammad Diasty
13
5 AALLCCOOHHOOLL AANNDD TTHHEE LLIIVVEERR
Alcohol is the most common cause of liver injury in the developed world.
Alcoholic liver disease can be considered in three overlapping phases with distinct pathological
and clinical features – fatty liver (or steatosis), alcoholic hepatitis and cirrhosis.
The relationships between these phases, the effect of drinking behaviour, and the incidence
of histological lesions in biopsy surveys of heavy drinkers are shown in Figure 1.
Normal
(0-30%)
→
←
Steatosis
(60-100%)
→
←
Steatohepatitis
(20-50%)
→
←
Fibrosis/cirrhosis
(<10%)
Fig 1 Pathological changes in the liver of heavy drinkers
(Percentages represent the number of heavy drinkers with this histology.)
Pathology and pathogenesis
Fatty liver is the initial and most common finding in heavy drinkers.
It is characterized by accumulation of triglyceride in hepatocytes. The distribution of lipid
can be macrovesicular (hepatocytes are distended by a single vacuole), or microvesicular.
The most important factors in the pathogenesis are:
• inhibition of fatty acid oxidation due to inhibition of the transcription factor PPAR‐α
• increased synthesis and import of fatty acids into the liver due to up‐regulation of the transcription factor
SREBP‐1c by TNF‐α and endoplasmic reticulum (ER) stress
• inhibition of triglyceride export from the liver via acetaldehyde and TNF‐α.
Alcoholic hepatitis
Characterized histologically by hepatocyte injury, a neutrophil infiltrate and pericellular
(‘chickenwire’) fibrosis, all of which occur in a predominantly perivenular (zone 3) distribution.
Similar features are seen in several other conditions, including obesity and diabetes, in which
they are termed ‘non-alcoholic steatohepatitis’.
Current evidence suggests a role for at least four mechanisms of injury in alcoholic hepatitis
that may interact:
• Oxidative stress arises during ethanol metabolism in hepatocytes and results in peroxidative damage to
membrane phospholipids. Damage to mitochondrial membranes is probably the critical event leading to
necrosis and apoptosis.
• ER stress arising as a result of acetaldehyde and homocysteine accumulation which results in inflammation
and apoptosis as well as increasing oxidative stress and inducing steatosis.
• Endotoxin‐mediated release of the pro‐inflammatory cytokine tumour necrosis factor‐α (TNF‐α) may
occur; via effects on mitochondria, this may contribute further to oxidative stress and hepatocyte
apoptosis.
• Immunological mechanisms may be directed against neo‐ antigens that arise from the covalent binding of
acetaldehyde and lipid peroxidation products to proteins, resulting in the formation of adducts (the product
of an addition reaction of the two compounds).
Fibrosis and cirrhosis
Collagen deposition in a peri-sinusoidal distribution enveloping hepatocytes is the hallmark
of alcoholic liver fibrosis. It progresses to micronodular cirrhosis, which becomes
macronodular following abstention.
Classically, alcohol related fibrosis is considered to represent a healing response to preceding
alcoholic hepatitis; fibrosis-producing hepatic stellate cells are activated by cytokines
released during hepatic injury.
Risk factors
Alcohol dose and pattern of intake
Above a risk ‘threshold’ of about three standard drinks per day, there is a steep dose-
dependent increase in the relative risk of cirrhotic or non-cirrhotic liver disease.
17. Basic Hepatology Part I Muhammad Diasty
14
Body weight and type 2 diabetes
Greater body mass index and fasting blood glucose have recently been shown to be
independent risk factors for liver fibrosis in heavy drinkers.
This probably results from the known association between obesity and insulin resistance with
hyperinsulinaemia and glucose having direct fibrogenic effects on hepatic stellate cells, the
main scar–producing cells in the liver.
Genetics
Women are more susceptible to alcoholic liver disease than men.
Clinical features
•Presentation ranges from an incidental finding to acute liver failure with encephalopathy
or decompensated chronic liver disease with portal hypertension.
•Patients often present with symptoms unrelated to the liver (e.g. early morning nausea,
diarrhoea, psychosocial problems).
•Patients with severe alcoholic hepatitis often present after a period of abstention following
a prolonged drinking bout.
•Alcohol abuse leads to a multisystem disorder; symptoms and signs of extrahepatic disease
must be sought.
•In patients with liver disease, an alcoholic aetiology is suggested by parotid enlargement,
Dupuytren’s contractures or an increase in γ-glutamyltransferase, MCV or serum IgA.
•Liver biopsy should be considered, to determine prognosis and to exclude other diseases
such as haemochromatosis, which are present in up to 20% of heavy drinkers.
Indices for liver dysfunction
The severity of alcoholic hepatitis can be assessed using a number of simple quantitative
indices, e.g.:
Maddrey’s discriminant function (DF): the assessment of the outcome of alcoholic liver
disease is simplified by developing a discriminate function.
DF = bilirubin (mg/dl) + 4.6 × prolongation of prothrombin time (seconds)
Patients with a DF greater than 32 have a 50% chance of dying during current hospitalization.
Management
General measures to treat acute and chronic alcoholic hepatitis:
1) Marked reduction in alcohol intake is the cornerstone of management.
2) Management of patients with cirrhosis (see cirrhosis).
Specific therapies for acutely decompensated alcoholic liver disease:
1) Corticosteroids (prednisolone, 40 mg/day for 1 month) have been reported to increase short‐ term survival
from 65% to 85% in patients with severe disease as determined by a DF > 32.
2) Pentoxifylline (Trental SR®
400 mg tab) ‐400 mg PO t.i.d.: Recognition of the role of TNF‐α in disease
pathogenesis has lead to several trials of therapy aimed at this pro‐inflammatory cytokine. Most recently, a
beneficial effect on short‐term survival has been reported.
3) Diet: Parenteral amino acids improves clinical state. Also magnesium, potassium and phosphate.
4) Thiamine: must be administerd to prevent Wernicke’s encephalopathy.
Specific therapies for decompensated chronic alcoholic liver disease:
1) Drug therapy: cholichicine and propylthiouracil demonstrated efficacy, however these are not standard
treatments for chronic alcoholic liver disesse.
2) Antioxidant therapy: they have varying, incompletely satisfying effects. S‐adenosyl‐methionine, vitamin E,
vitamin A, silymarin and polyenylphosphatidylcholine.
3) Liver transplantation
Patients with decompensation despite 6 months’ abstinence and no severe extrahepatic complications of
alcohol abuse (e.g. cardiomyopathy, cerebral dysfunction) are candidates for liver transplantation.
The results of transplantation for alcoholic liver disease are generally excellent.
18. Basic Hepatology Part I Muhammad Diasty
15
6 NNOONN--AALLCCOOHHOOLLIICC FFAATTTTYY LLIIVVEERR DDIISSEEAASSEE
Definition
NAFLD describes a spectrum of abnormalities from hepatic steatosis alone to steatosis with
associated necroinflammatory changes and variable degrees of fibrosis.
NASH is a clinical-pathological syndrome of steatosis and associated hepatic necro-
inflammatory changes that is diagnosed only by liver biopsy.
The reported prevalence of NAFLD is about 20–30% and that of NASH of around 2–3%.
Pathogenesis
A “two hit” theory implicates both insulin resistance and oxidative stress as potential factors
leading to steatohepatitis, and, eventually, fibrosis and cirrhosis (Figure 2).
Fatty acid accumulation in the liver (the “first hit”) may occur secondary to an imbalance
between fatty acid delivery to and export from the liver → As fatty acid retention increases,
steatosis develops.
The mechanism by which steatosis progresses to steatohepatitis, and subsequently to fibrosis
is unclear, but oxidative stress has been proposed as the “second hit.”
Components of this additional factor include oxidative stress, mitochondrial abnormalities,
tumour necrosis factor (TNF)-α and hormones, such as adiponectin and leptin. Adiponectin,
which is produced by peripheral fat, has both anti- inflammatory and antifibrotic effects.
Mitochondrial injury, leading to ATP depletion, reactive oxygen species generation, lipid
peroxidation, and cytokine induction may mediate hepatocyte injury.
Fibrosis also requires the activation of the hepatic stellate cell, which produces collagen.
Profibrogenic factors in the setting of NAFLD include leptin, angiotensin II and
norepinephrine.
Figure 2. Two hit hypothesis for NAFLD.
19. Basic Hepatology Part I Muhammad Diasty
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Risk factors:
Table 7 Risk factors and conditions associated with NAFLD
Metabolic Medications Other Conditions
Obesity*
Type II Diabetes Mellitus*
Hyperinsulinemia*
Rapid weight loss, including
starvation and bypass surgeries
TPN
Lipodystrophy
• Amiodarone
• Calcium channel blockers
• Aspirin
• Glucocorticoids
• Synthetic estrogens
• Tetracycline
• Antivirals, such as zidovudine and
didanosine
• Tamoxifen
• Valproic acid
• Methotrexate
• Cocaine
Inflammatory bowel disease
Small intestinal diverticulosis with
bacterial overgrowth
HIV infection
Bacillus cereus toxin
*major risk factors
Clinical features and investigations (table 8)
Table 8
Clinical Features of Non-Alcoholic Steatohepatitis (NASH)
Symptoms and physical findings
• Fatigue (correlates poorly with histological stage)
• Vague aching right upper quadrant pain (usually mild but may be mistaken for gallstone disease)
• Hepatomegaly
• Increased waist circumference indicates central adiposity
• Acanthosis nigricans: (hyperpigmentation in armpits, over knuckles) can be a sign of hyper‐insulinaemia,
especially in children with NAFLD.
• Lipodystrophy
Laboratory
• Aminotransferase elevations (rarely more than 10‐fold above upper reference range; aminotransferases can be
in the normal range with NASH or cirrhosis)
• ALT typically greater than AST (AST > ALT suggests occult alcohol abuse or significant fibrosis)
• Elevated insulin x glucose product (basis of the HOMA‐IR and QUICKI)
• Hypertriglyceridemia
• Positive antinuclear antibody in about one‐third of patients
• Abnormal iron indices
Noninvasive Biomarkers in NASH
See table 9
Imaging
• No imaging modality can reliably identify fibrosis and stage the disease
• Ultrasound demonstrates a “bright” liver but is insensitive (cannot detect steatosis less than 25–30%) and non‐
specific (increased echogenicity of fibrosis or cirrhosis can be mistaken for steatosis)
• CT allows accurate quantification of fat but at increased cost
• MR imaging and spectroscopy allow measurement of fat content and possibly ATP levels in fatty liver
Liver biopsy
Specific histological findings of NASH:
1) Steatosis: fat droblets within hepatocytes.
2) Inflammation: mixed neutrophilic and mononuclear cell infilterate within the lobule.
3) Mallory bodies: esinophilic cytoplasmioc aggregates of cellular proteins.
4) Glycogen nuclei: clear intranuclear vacuoles that nearly fill the nucleus.
5) Fibrosis: similar to alcoholic liver disease
HOMA-IR, homeostasis model assessment method for insulin resistance; QUICKI, quantitative insulin sensitivity check
index; CT, computed tomography; MR, magnetic resonance; ATP, adenosine triphosphate.
20. Basic Hepatology Part I Muhammad Diasty
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Table 9 Noninvasive Biomarkers in NASH
Serum biomarker Marker of Findings
ROS Oxidative stress
Conflicting results: some correlation between NASH and
increased level of ROS
Leptin Insulin resistance Conflicting results: higher levels in some studies
Adiponectin Insulin sensitivity ADP lower in NASH patients
High-sensitivity CRP Systemic inflammation Conflicting results: some increased high sensitivity CRP
with NASH compared with NAFLD
Cytokeratin 18 Hepatic apoptosis Significantly higher in NASH
Diagnosis
Diagnosis requires the exclusion of those drinking more than 20 g of alcohol per day.
A diagnosis of NAFLD can usually be made with confidence based clinically on:
• elevated serum transaminases
• negative chronic liver disease screen
• elevated BMI
• ultrasound evidence of fat
• features of the metabolic syndrome − type 2 diabetes, hypertension, central obesity (waist circumference >102
cm in men, 88 cm in women), elevated triglyceride level.
Clinical features, predicting NASH and thus those at risk of progression to cirrhosis:
• Older age >45 years
• Increasing body mass index (BMI) >30 kg/m2
• Type 2 diabetes mellitus or elevated fasting glucose
• AST > ALT
Differential diagnosis
Because the diagnosis of NASH is based on histological findings, alcoholic hepatitis must be
excluded from the outset.
Other causes of steatohepatitis that must also be excluded with appropriate clinical and
laboratory evaluation are Wilson’s disease and drug-induced steatohepatitis.
Table 10 Features of Either Non-Alcoholic Steatohepatitis (NASH) or Alcoholic Steatohepatitis (ASH)
Features associated with NASH Features associated with ASH
Clinical/historical
Alcohol <20 g/day (corroborated history)
Type 2 diabetes
Obesity/overweight
Hypertension
Polycystic ovary syndrome/dysmenorrhea
Alcohol use/abuse
Anorexia
Leukocytosis, fever
Physical exam
Obesity
Acanthosis nigricans
Jaundice
Laboratory
ALT > AST (unless cirrhotic)
Normal bilirubin
AST > ALT
Elevated bilirubin
Hypoalbuminemia
Peripheral leukocytosis
Liver biopsy
Poorly formed or undetectable Mallory bodies
Steatosis always present (except in cirrhosis)
Glycogenated nuclei
Well‐formed, numerous Mallory bodies
Steatosis may be less prominent
Sclerosing hyaline necrosis and central vein injury
Pathogenesis
Fat accumulation is primary
Injury is secondary to fat (oxidant stress?)
Mitochondrial dysfunction?
Acetaldehyde toxicity?
Prognosis
Cirrhosis is major adverse outcome, risk is about 1% Liver failure, risk up to 50%
21. Basic Hepatology Part I Muhammad Diasty
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Management (figure 3)
There is no approved therapy for NAFLD.
Currently, patients with NAFLD are advised to address risk factors for metabolic syndrome,
which include insulin resistance, systemic HTN, and hypercholesteremia and obesity.
Interventions are currently targeted to patients with NASH rather than simple steatosis
because of its potential to progress to cirrhosis.
Diet
Insulin resistance has been shown to worsen with saturated fat consumption but may improve
with a high-fiber diet.
Weight Loss
The initially attempted management of NAFLD includes weight reduction through lifestyle
modifications with diet and exercise.
Weight loss has been shown to:
Decrease adipose tissue, which leads to reduced insulin resistance.
Increase insulin sensitivity through peripheral lipolysis, inhibiting lipid synthesis and enabling fatty acid
oxidation.
A target loss of 10% of the baseline weight should be the initial goal for a BMI greater than 25;
this reduces aminotransferase levels and diminishes hepatomegaly.
Weight loss through diet and exercise should be gradual. Rapid weight loss exceeding 1.6
kg/wk has the potential to worsen steatohepatitis and cause gallstones.
Weight loss can be achieved by:
a) Calorie Reduction
b) Exercise
c) Antiobesity Medications
Two medications have been approved for weight loss: orlistat and sibutramine.
►Orlistat is an enteric lipase inhibitor that blocks the absorption of long-chain FA and cholesterol.
►Sibutramine stimulates weight loss by inhibiting serotonin and norepinephrine reuptake and
increasing satiety.
►Rimonabant, another antiobesity medication, is an antagonist of the cannabinoid receptor type 1
(CB1).
►Incretin analogues (Exendin-4)
d) Bariatric Surgery
Surgery is recommended for patients with a BMI greater than 40 or a BMI greater than
35 with comorbid conditions.
Pharmacologic Treatment of Insulin Resistance
Biguanide
Metformin (Cidophage®
500, 850 tab) is a biguanide that improves insulin resistance by:
Decreasing the production of hepatic glucose and increasing the uptake of peripheral glucose by
skeletal muscle and fatty acid oxidation
Improve TNF-α-induced insulin resistance
A study using metformin 2 gm daily showed biochemical improvement after 3 months but no
significant difference at month 12.
Thiazolidinediones
Thiazolidinediones are oral antidiabetic medications that are currently being tested for
treatment of NASH. They bind to peroxisome proliferator-activated receptor gamma (PPAR-γ)
and decrease insulin resistance by various mechanisms:
Stimulate free fatty acid oxidation
Increase adiponectin expression
Decrease triglycerides and TNF-α in obese rats
Reduce leptin levels
Troglitazone (Rezulin® 200 mg tab) was administered (at a dose of 400 mg daily for up to 6 months)
Rosiglitazone (Avandia® & Rosidexx® 4 mg tab) 4 mg twice daily for 48 weeks
The major side effect is weight gain.
22. Basic Hepatology Part I Muhammad Diasty
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Lipid-Lowering Agents
Elevated triglycerides and low HDL are components of the metabolic syndrome associated with
NAFLD. Several studies have investigated the effect of hyperlipidemia treatment on NAFLD.
►Hydroxymethylglutaryl-CoA reductase inhibitors are known to potentially cause hepatotoxicity; 2
studies show that it does in fact reduce ALT.
►Pravastatin 20 mg daily was used to treat hyperlipidemia for 6 months; liver enzymes normalized and
hepatic inflammation decreased.
►Gemfibrozil, a fibric acid derivative, is another lipid-lowering agent; patients treated with 600 mg daily
for 4 weeks showed biochemical improvement.
►Ezetimibe blocks cholesterol absorption in the intestine.
Antioxidants
Oxidative stress plays a major role in the multi-hit hypothesis of NAFLD. Several studies have
evaluated the effects of antioxidants in patients with NAFLD.
Betaine is a metabolite of choline and increases S-adenosylmethionin levels, which has been
shown to be hepatoprotective.
Ursodeoxycholic Acid
The hepatoprotective effects of ursodeoxycholic acid (UDCA) are currently under
investigation as potential treatment for NAFLD.
UDCA at 13 to 15 mg/d showed a reduction in steatosis and serum liver enzyme levels after 2
years of treatment.
Angiotensin-Converting Enzyme Inhibitor/Angiotensin Receptor Blocker
Several studies have attempted treatment of the metabolic syndrome.
ACE-Is and ARBs may prevent type 2 diabetes in patients with HTN or congestive heart failure.
ACE-ls suppress the renin angiotensin system. ARBs, irbesartan, and telmisartan, are thought
to activate PPAR-γ and decrease insulin resistance.
Other Novel Agents
►Pentoxifylline (Trental SR®
400 mg tab) has also been used to treat NAFLD. It functions by
inhibiting TNF-α, which is implicated in the multi-hit hypothesis of NASH.
►Probiotics are under investigation for NASH treatment because some studies have suggested
an overgrowth of intestinal bacteria in NASH. Researchers have shown improved ALT and
other markers of lipid peroxidation with the use of probiotic VSL#3 in NAFLD patients.
►Nateglinide (insulin secretagogue), improves biochemical and histologic parameters in
diabetic patients with NASH.
Prognosis
Simple fatty liver disease
Those individuals identified as having simple fatty liver, either clinically or histologically,
have a good prognosis, with only 2% developing progressive fibrosis within 10 years.
NASH
Patients with NASH often die of liver disease rather than the cardiovascular manifestations of
the metabolic syndrome.
Progression to cirrhosis, like hepatitis C infection, is slow with 5–20% reported to progress
within 10 years.
Once cirrhosis has developed, 45% of these patients will develop complications within 10
years.
23. Basic Hepatology Part I Muhammad Diasty
Figure 3 Potential pathophysiologic effects of therapies that are under investigation.
The development of hepatic steatosis and subsequent steatohepatitis is multifaceted.
NB:
Clinical sstimation of insulin resistance
The ability to estimate insulin resistance and thus predict the presence of complications associated with
this disorder has become necessary in the management of patients with NAFLD.
The presence of insulin resistance suggests that therapeutic options aimed at improving insulin sensitivity
may be beneficial, whereas the occasional patient with NAFLD but normal insulin sensitivity should be
further evaluated for uncommon or unrecognized causes such as other metabolic abnormalities or covert
alcohol abuse.
Some of the commonly used methods to assess insulin sensitivity and the practical issues related to reliably
measuring serum insulin concentrations have been reviewed.
Despite potential problems, biochemical assessment of insulin resistance commonly relies on measuring
serum insulin levels, and two measures, the homeostasis model assessment method for insulin resistance
(HOMA-IR) and the quantitative insulin sensitivity check index (QUICKI), use the fasting insulin level
multiplied by the fasting glucose level.
Although HOMA-IR has been widely used, QUICKI is a reasonable estimate of the glucose clamp-derived
index of insulin sensitivity (SIClamp) because the QUICKI is linearly related to the SIClamp. This may be due to
the fact that both the QUICKI and the SIClamp calculations use log-transformed values.
Nonetheless, the QUICKI and the HOMA-IR are both based on the product of the fasting insulin multiplied by
the fasting glucose (Figure 4), a point missed by many authors when they calculate that the two are found
to be highly correlated in a given study.
Fig 4. Clinical estimation of insulin sensitivity.
Two easily used measures of insulin sensitivity are the
homeostasis model assessment of insulin resistance
(HOMA‐IR) and the quantitative insulin sensitivity check
index (QUICKI).
Both indices are derived from the fasting insulin level
multiplied by a simultaneously obtained fasting glucose
level and are therefore mathematically directly related
to each other. The QUICKI is log‐transformed, which
makes it linearly related to the SIClamp, a more accurate
measure of insulin sensitivity based on the insulin clamp
technique.
20
24. Basic Hepatology Part I Muhammad Diasty
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7 VVIIRRAALL HHEEPPAATTIITTIISS
Table 11. Properties and clinical characteristics of viruses.
HAV HBV HCV HDV HEV
Virus
Family
Envelop
Genome
Picornaviridae
No
RNA
Hepadnaviridae
Yes
DNA
Flaviviridae
Yes
RNA
Plant viroid
Yes
RNA
Caliciviridae
No
RNA
Incubation 2‐7 weeks 4‐25 weeks 2‐20 week 3‐6 weeks 3‐9 weeks
Transmission Fecal‐oral
Percutaneous,
sexual, perinatal
Percutaneous,
(especially
injection drug
use), sexual (rare),
perinatal (rare)
Percutaneous,
intrafamily
Fecal‐oral
Severity of
acute illness
Usually mild,
particularly in
children
Adults: 70%
subclinical, 30%
clinical, < 1% severe
Newborn: subclinical
Usually subclinical,
1% severe
May be severe May be severe;
20% mortality in
pregnancy
Chronic
infection
None 90% neonatal, 50%
infants, 20%
children, < 1%
adults
> 85% 5% with HBV
coinfection,
> 80% with HBV
superinfection
None
Vaccine Available Available None None Efficacy
demonstrated in
clinical trials
Hepatitis A and E
Hepatitis A and E are enterically transmitted diseases with several common features:
• The aetiological agents hepatitis A virus (HAV) and hepatitis E virus (HEV) are RNA viruses.
• The route of transmission is mainly faecal–oral.
• The clinical course is acute, self-limiting hepatitis with no progression to chronic liver disease.
Clinically, HAV and HEV infections are indistinguishable.
In some patients, the infection is asymptomatic, resulting in virus-specific immunity. There is
no chronic carrier state.
Hepatitis A
Viral characteristics: see table 11
Epidemiology
HAV infection is enteric and associated with poor sanitation; it usually occurs in children.
Importantly, 90% of HAV infections in children under 5 years of age are asymptomatic; the
prevalence of symptomatic anicteric or icteric hepatitis A increases with age.
Water-borne and food-borne transmission is responsible for HAV endemicity in developing
countries and occasionally cause extensive outbreaks in countries in which the infection is at
a low prevalence. Shellfish are an important source of food-borne HAV infection.
In developed countries
Person-to-person transmission is the most common source of HAV infection.
Intrafamilial spread, person-to-person contact at schools and day-care centres and
homosexual activity are most commonly involved.
Socioeconomic improvements and better hygiene standards have reduced the prevalence of
HAV antibody in developed countries; as a result, the mean age of exposure to HAV and the
number of symptomatic cases may increase.
25. Basic Hepatology Part I Muhammad Diasty
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In developing countries
Childhood exposure to HAV is almost universal. The main route of transmission is faecal–oral.
Occasionally, HAV is transmitted by blood products or through illicit use of injectable drugs.
Pathogenesis
HAV replication in vivo occurs predominantly in hepatocytes without cytopathic effect;
large quantities of virus are secreted into biliary canaliculi.
In addition to faecal shedding of the virus, there is sustained viraemia, which persists from
the earliest phase of HAV infection until onset of liver injury.
Liver injury is immune mediated by natural killer cells, virus-specific CD8+ cytotoxic T
lymphocytes and non-specific cells recruited at the site of inflammation.
Clinical features
Hepatitis A infection usually presents in one of five different clinical patterns:
1. Asymptomatic (not jaundiced)
2. Symptomatic (jaundiced): self-limited to approximately 8 weeks
3. Cholestatic, in which jaundice lasts 10 weeks or more
4. Relapsing, consisting of two or more bouts of acute HAV infection occurring over a 6—10-week
5. FHF
The incubation period is 2–7 weeks; the duration appears to be related to the infecting dose.
Prodromal symptoms, patients may have comprising malaise, loss of appetite, nausea,
vomiting and fever for a few days
The onset of dark urine is usually the first clinical indication of disease, followed by jaundice
and pale stools. Colour returns to the stools after 2–3 weeks; this is a sign of disease resolution.
Age is the most important determinant of the severity of hepatitis A; the case fatality rate
may be as high as 2.7% in patients over 49 years of age and higher in those with chronic liver disease.
A small subset of patients develop extrahepatic manifestations, which are listed in Table 12.
Table 12
Extrahepatic Manifestations of Hepatitis A Virus Infection
Gastrointestinal
Acalculous cholecystitis
Pancreatitis
Hematologic
Aplastic anemia
Autoimmune hemolysis
Autoimmune thrombocytopenic purpura
Hemolysis (in patients with G6PD)
Red cell aplasia
Other
Cutaneous vasculitis
Cryoglobulinemia
Reactive arthritis
Neurologic
Guillain‐Barré syndrome
Mononeuritis
Mononeuritis multiplex
Postviral encephalitis
Transverse myelitis
Renal
Acute tubular necrosis
Interstitial nephritis
Mesangial proliferative glomerulonephritis
Nephrotic syndrome
Complications
Fulminant hepatitis: the risk of is 0.14–0.35%.
Cholestatic hepatitis with itching and jaundice lasting up to 18 weeks. In such cases, a short
course of rapidly tapered corticosteroids may accelerate resolution.
Relapsing course with a second hepatitis flare 30–90 days after the initial peak. This
ultimately resolves without chronic sequelae.
26. Basic Hepatology Part I Muhammad Diasty
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Diagnosis
Liver functions:
• Serum bilirubin (principally the conjugated fraction) is elevated in icteric hepatitis.
• Albumin may be reduced in severe cases.
• ALT levels can be as high as 4000–5000 IU/litre
Serology:
• HAV IgM Confirms acute HAV infection. Undetectable after 3-4 months although 25%
may persist up to 6 months or more
• HAV IgG Indicates previous exposure and immunity
• HAV RNA Not clinically useful as the virus is usually undetectable at the time of
clinical manifestation
Urine analysis: for urobilinogen and bilirubin is important because the presence of
urobilinogen may be the first sign, even before jaundice.
Management
There is no specific treatment for hepatitis A.
Management is supportive (adequate fluid intake in the form of water and fruit juices, bed-
rest, avoidance of major physical exercise, no alcohol) and patients at risk of complications
are monitored monthly.
More frequent monitoring of liver function tests is important in patients with very high ALT levels
or deep jaundice, particularly when prothrombin time is prolonged.
Prevention
Improvement in hygiene and sanitation is the primary preventive measure.
Postexposure prophylaxis should be given during the first 2 weeks postexposure, with serum
immunoglobulins at a dose of 0.02 mL/kg by IM injection. Active immunization with hepatitis
A vaccine can be given at the same time without negative effect on immunity.
Hepatitis A vaccination can interrupt HAV transmission in community-wide outbreaks. There
are 2 recombinant hepatitis A vaccines.
Pure hepatitis A vaccines (Havrix® and VAQTA®) are, indicated for individuals 2 years of age and
older—with two doses, the second given 6 to 18 months after the first one.
Combined hepatitis A and B vaccine (Twinrix®) is given IM at three doses—at 0, 1 month, and 6
months to persons 18 years or older.
Vaccination-induced protective antibodies develop in more than 95% after the second dose.
The first dose of vaccine should be given at least 3 weeks before travel to endemic areas.
Vaccination is recommended for:
(1) Children living in endemic areas
(2) Persons at increased risk, such as travelers to endemic regions, illegal drug users, workers in
research laboratories who work with HAV, and individuals with clotting factor disorders
(3) Persons with chronic liver disease, especially chronic hepatitis B or C
(4) Outbreaks in communities with higher intermediate rates of hepatitis A.
Prevaccination testing for adults is cost-saving; postvaccination testing is not needed because
of the 95% response rate. Immunity is expected to last at least 20 years.
Hepatitis E
Viral characteristics and epidemiology (table 11)
Four genotypes of HEV have currently been identified:
Genotype 1 has been isolated from tropical countries in Asia and Africa
Genotype 2 was found in Mexico, Nigeria and Chad
Genotype 3 has worldwide distribution, including Europe, Asia, North and South America.
Genotype 4, was found exclusively in Asia.
Genotypes 3 and 4 have been identified in swine, but also in wild animals such as boar and deer.
27. Basic Hepatology Part I Muhammad Diasty
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HEV infection is endemic in Asia, Africa, the Middle East and Central America, particularly in
areas with inadequate sanitation.
Characteristic features of HAV outbreaks include a higher rate of symptomatic hepatitis E in
15–40-year-olds and a particularly high fatality rate (about 20%) in HEV-infected pregnant women.
Unlike HAV, immunity to HEV is not life-long. The large proportion of seronegative individuals
in the population probably accounts for the frequent epidemics of hepatitis E in developing
countries. The risk of epidemics is high during the pre-monsoon and monsoon ﻣﻮﺳﻤﻴﺔ رﻳﺢ seasons.
Transmission
• In most outbreaks, the route of transmission is water contaminated with faeces. Food-
borne transmission has been suggested in some outbreaks.
• Unlike HAV, HEV infection may be zoonotic. HEV RNA has been found in the faeces of wild
pigs, and serological evidence of infection was found in pigs and sheep in endemic regions.
• Person-to-person transmission of HEV appears to be less common than for HAV.
Clinical course
The symptoms of hepatitis E are similar to those of other forms of acute viral hepatitis.
The average incubation period is 40 days (range 15–60 days).
In most patients, resolution of hyperbilirubinaemia and abnormal serum ALT occurs within 3
weeks (range 1–6 weeks) and there is no clinical or histological evidence of chronic hepatitis.
The severity of hepatitis E is related to the dose of virus; low levels can infect without
causing disease.
A cholestatic form of hepatitis E may have a protracted course of 8–12 weeks, or occasionally
up to 24 weeks.
Pregnant women are at greatest risk of a serious (complicated) course in hepatitis E. In the
third trimester, fatality is 25% and fetal morbidity and mortality are high.
Diagnosis
There is usually elevation of the transaminases and total bilirubin. Jaundice often sets in
after the peak of the transaminases.
There are serologic tests to identify antibodies against HEV and to directly detect HEV
antigens, however, these tests are largely for research purposes and will not be available in
most labs.
An important part of making a diagnosis of acute HEV infection includes excluding the
other causes of acute hepatitis serologically including hepatitis A, B, C, D, as well as CMV
and EBV.
Management and treatment
The mainstay of the management of cases of acute HEV infection is supportive care.
If fulminant hepatic failure develops then expeditious transfer to a liver transplant center
is imperative.
It is not necessary to treat household contacts since this is not a common route of
transmission of HEV.
Prevention
An important measure to try to prevent HEV infection is good sanitation.
Boiling water does appear to inactivate HEV.
There is no vaccine against HEV at this time, and there is no clear evidence that the
administration of anti-HEV immunoglobulin is beneficial in decreasing transmission.
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Hepatitis B
Classification and structure
Hepatitis B virus is a member of the Hepadnaviridae (hepatotropic DNA virus) family.
HBV virions are double-shelled particles, with an outer lipoprotein envelope that contains
three related envelope glycoproteins (or surface antigens).
Within the envelope is the viral nucleocapsid, or core.
The core contains the viral genome, a circular, partially duplex DNA, and a polymerase that is
responsible for the synthesis of viral DNA in infected cells. (Fig 5)
Fig. 5. The HBV genome is a partially
double‐stranded circular DNA sequence
approximately with a complete minus and
incomplete plus strands.
The two DNA strands are held in a circular
configuration by cohesive overlapping of the
5` ends of the strands, which contain the DR1
and DR2 direct repeats.
The virus encodes several mRNAs (outer wavy
lines) which are used for the production of
the viral proteins:
S (surface or envelope)
P (polymerase)
C (core)
X.
Figure 6. Life cycle of hepatitis B virus.
The receptor for viral entry has not been identified. Once inside the cell, the virus undergoes uncoating and
nuclear entry of the HBV genome occurs, followed by repair of the single‐stranded DNA strand and formation of
the covalently closed (ccc) DNA template.
Viral transcripts are formed for the HBsAg, DNA polymerase, X protein, and the RNA pregenome; the pregenome
and polymerase are incorporated into the maturing nucleocapsid.
The surface protein enveloping process occurs in the endoplasmic reticulum. Some of the nonenveloped
nucleocapsid recirculates back to the nucleus and the cycle begins again. Excess tubular and spherical forms of
HBsAg are secreted in great abundance.
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Viral genes and proteins
The HBV genome has only four long open reading frames.
The preS–S (presurface–surface) region of the genome encodes the three viral surface
antigens. The most abundant protein is the S protein (which is known as HBsAg).
The preC–C (precore–core) region encodes hepatitis B core antigen (HBcAg) and hepatitis
B e antigen (HBeAg).
The P coding region is specific for the viral polymerase, a multifunctional enzyme
involved in DNA synthesis and RNA encapsidation.
The X open reading frame encodes the viral X protein (HBx), which modulates host-cell
signal transduction and can directly and indirectly affect host and viral gene expression.
HBV genotypes
HBV is classified into eight major genotypes (A–H) based on an inter-group divergence in the
complete nucleotide sequence.
Table 13
Hepatitis B Genotypes and Their Possible Clinical Associations
Eight well characterized genotypes (A–H)
Different geographic distributions
A Northwestern Europe, North America, Central Africa
B Southeast Asia, including China, Japan and Taiwan (increasing prevalence in North America)
C Southeast Asia (increasing prevalence in North America)
D Southern Europe, Middle East, India
E West Africa
F Central and South America, American natives, Polynesia
G USA, France
H Central and South America
Proposed clinical associations
Time to HBeAg seroconversion and probability of HBsAg loss (B shorter than C)
Response to treatment with interferon‐a (A>B>C>D)
Precore/core promoter mutant frequency (precore not selected with genotypes A and F)
Liver disease activity and risk of progression (B<C in Asia)
Evolution to chronic liver disease (A<D)
Hepatocellular carcinoma risk (B<C)
HBV DNA level (lower in C vs A, B, D (HBeAg‐positive); higher in D vs A–C (HBeAg‐negative)
Epidemiology
Hepatitis B virus (HBV) infection is parenterally transmitted; it occurs in:
babies born to HBV-infected mothers
after transfusion of blood and blood products
intravenous drug use
sexual contact.
The outcome of HBV infection depends on age and on genetic factors determining the
efficiency of the host immune response.
Almost 100% of children infected at birth, but only 2–10% of those infected in adult life, develop
persistent infection. Persistence of infection following acquisition of the virus in adulthood is most common
in men and in patients with immunodeficiencies.
Pathogenesis
The pathogenesis of HBV-related liver disease is largely due to immune-mediated
mechanisms. However, in some circumstances HBV can cause direct cytotoxic liver injury.
•• Immune-mediated liver injury
Liver injury related to HBV is generally thought to be related to cytotoxic T-lymphocyte
(CTL)-mediated lysis of infected hepatocytes. These cells recognize viral antigens presented
in association with class I histocompatibility antigens on the hepatocyte membrane causing
apoptosis of the infected hepatocytes.
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Events that enhance immune clearance as in spontaneous or interferon-induced HBeAg
seroconversion are often accompanied by exacerbations of liver disease, with flares in serum
ALT levels and lobular necrosis.
•• Direct cytopathic effects
In general, HBV is not a cytopathic virus. In most patients with chronic hepatitis B, there is no
direct correlation between viral load and severity of liver disease. This is particularly true in
young adults who acquired HBV infection perinatally. These individuals tend to have very
high serum HBV DNA levels and abundant intrahepatic virus, but are usually asymptomatic
with normal ALT levels and minimal histologic changes.
Nevertheless, direct cytopathic liver injury can occur when the viral load is very high, as in
some patients with recurrent hepatitis B post-liver transplant who develop fibrosing
cholestatic hepatitis (FCH).
•• Role of viral mutants
Mutations in the precore region or in the core promoter region hamper the production of
HBeAg. The patients with these variants have chronic hepatitis B with undetectable HBeAg
and detectable anti-HBe despite the presence of moderate or high level HBV replication.
HBeAg-negative chronic HBV is generally more severe (higher risk of cirrhosis and HCC).
In addition even if the response on therapy is relatively good, the risk of relapse after therapy
is very high.
•• Hepatocarcinogenesis
Several lines of evidence support an etiologic association between chronic HBV infection and
the development of HCC.
Integration of HBV DNA into host chromosomes can be found in the neoplastic liver tissues
from most HBsAg-positive patients with HCC. The mechanism may be:
Integration of HBV DNA into the host genome may induce carcinogenesis by:
activating cellular proto‐oncogenes or suppressing growth‐regulating genes
inducing host chromosomal deletions or translocations
Chronic liver injury, inflammation and regeneration.
Diagnosis
Serologic Tests
The fundamental way to diagnosis HBV includes serologic tests looking for the presence of
HBV-specific antigens, antibodies, and viral DNA.
Hepatitis B Surface Antigen
HBsAg is a marker of acute and chronic infection.
When it persists beyond 6 months, it signifies chronic infection.
The disappearance of HBsAg is followed by the appearance of HBsAb is the hallmark of recovery.
The window period is that short period of time (weeks) during which HBsAg has become
undetectable, but before the HBsAb is detectable. If acute HBV is suspected, an HBcAb IgM
should be checked to make the diagnosis although there are conditions in which the
presence of HBcAb IgM does not signify acute infection.
Hepatitis B Surface Antibody
HBsAb is an important marker of recovery and of immunization.
Isolated HBsAb is most commonly the profile seen in individuals that have been successfully
immunized against HBV with the vaccination.
In cases of recovery after natural infection, there is typically detectable HBsAb and HbcAb,
although overtime the antibody levels may wane to the point that only HBsAb or HBcAb is
detectable.
Hepatitis B Core Antibody
While HBcAb is detectable throughout HBV infection (either IgM or IgG subclass), the core
antigen is typically located intracellularly and cannot be detected in the routinely used assays.
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HBcAb is an important marker of natural exposure to the virus and distinguishes individuals
who have had infection with the virus as opposed to those exposed only to the vaccination
against HBV.
In cases of immunization, there will never be detectable HBcAb.
It is detectable as IgM, which is usually a marker of more acute infection and as IgG in later
infection. It should be noted, however, that detectable HbcAb IgM does not always signify
acute HBV infection. It may remain detectable for up to several years after the acute
infection and may increase to detectable levels during exacerbations of hepatitis in cases of
chronic HBV. Therefore, a detectable HbcAb IgM needs to be placed in the context of the
individual.
After natural infection with HBV, the HBcAb IgG remains detectable whether the individual
recovers or develops chronic infection.
There are cases in which there may be only isolated HBcAb detected without detectable
HBsAg or HBsAb. The explanations for such a HBV profile may include:
the window period of acute HBV infection
years after recovery from HBV infection when the titer of HBsAb falls below detectable levels
after years of chronic infection when the HBsAg levels drop below detectable levels but without
neutralizing antibody (HBsAb) present.
Hepatitis E Antigen
HBeAg is a marker of HBV replication and infectivity. The absence of HbeAg does not ensure
that there is no HBV replication or infectivity, however.
The precore mutant strain of HBV does not produce HBeAg, but it still successfully replicates
and can cause progressive liver damage.
Hepatitis E Antibody
The loss of HBeAg and the appearance of the HBeAb is called seroconversion.
When seroconversion occurs, HBV DNA typically becomes undetectable and there may be
remission in terms of liver disease, although this is not always there case.
Hepatitis B DNA
The major role of HBV DNA assays is to assess HBV replication and appropriateness for
antiviral therapy. HBV DNA measurements are also important in assessing response to
therapy.
Traditionally, a cut-off of >105
copies/mL has been used to decide if treatment is indicated.
This cut off was decided on somewhat arbitrarily since this was the lower limit of detection
of the older non-amplified HBV DNA assays. This is not necessarily the precise clinically
relevant threshold at which a patient is likely to have progressive liver injury if untreated.
Indeed, there may be ongoing injury at lower levels; however, the precise threshold is
unknown.
It should be noted that in case of fulminant hepatic failure related to HBV infection, the
HBV DNA assay may be crucial to identifying the etiology of hepatic failure. In these cases,
HBsAg may be cleared by the time of presentation due to the overwhelming immune
response against the virus, which is also related to the fulminant course of the infection.
Recovery from HBV infection is usually associated with a loss of HBV DNA; however, despite
clinical recovery the more sensitive PCR assays may continue to detect low levels of HBV
DNA. This finding is explained by the idea that HBV recovery may actually represent
effective immune system control of the virus but not complete eradiation of the virus.
In early acute HBV one would expect to see a positive HBsAg, HBeAg, HBcAb IgM, and HBV DNA.
In later-recovering acute HBV, the HBV panel would show a positive HBcAb IgG (anti-HBc IgG),
HbsAb (anti-HBs), HBeAb (anti-HBe)
In chronic HBV, one would expect to see persistent HBsAg, HBeAg, and HBcAb (anti-HBc). There is
eventual loss of HBc IgM and possibly seroconversion (HBeAg lost with development of detectable
HBeAb/anti-HBe).
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Liver Biopsy
Liver biopsy may play an important role in assessing the degree of liver injury caused by
chronic HBV infection. The typical pathologic findings include:
primarily mononuclear inflammatory infiltrates in the portal tracts
periportal necrosis
varying degrees of fibrosis.
The degree of inflammation (grade) and amount of fibrosis (stage) can be assessed using the
histology activity index (HAI) or the Metavir score.
Immunostaining for HBsAg and HBcAg may be helpful. A characteristic finding on liver biopsy
of HBV infection includes ground-glass appearing hepatocytes which are full of HBsAg.
While it may be informative, the actual HBV antigen staining pattern is not correlated with
disease severity, however.
Table 14
Serodiagnosis of hepatitis B virus (HBV) infection
HBsAg antiHBs HBeAg antiHBe IgM
antiHBc
Total
antiHBc
HBV DNA ALT
Acute HBV + ‐ + ‐ + + Detectable Raised
Chronic HBV (wild
type)
+ ‐/+ + ‐ ‐ + >105
Raised
Chronic HBV
(precore variant)
+ ‐/+ ‐ + ‐ + >105
Raised
Inactive carrier + ‐/+ ‐ + ‐ + <105
Normal
Recovered ‐ ‐/+ ‐ + ‐ + Undetectable Normal
Vaccinated ‐ + ‐ ‐ ‐ ‐ Undetectable Normal
Course of chronic disease
Chronic HBV infection generally passes through a series of stages, both virologically and clinically.
Virological classification
‘HBe-positive virus’ infection
The form most commonly encountered in Northern Europe and North America where
genotypes A and B are most common.
The virus replicates and encodes infected liver cells to synthesize and secrete hepatitis Be
antigen (HBeAg). As a result, HBeAg can be detected in the serum.
Later, viral DNA can become integrated into the cellular DNA. At this stage, production of
hepatitis Bs antigen (HBsAg) can occur without viral replication.
‘HBe-negative virus’ infection
Has recently been recognized and is common with genotypes C and D.
This is a variant form of HBV which can lead to productive viral infection without secretion of
HBeAg. HBe-negative virus is also known as the ‘pre-core mutant’, reflecting the mutation
identified in the viral genome.
This form of the virus can emerge late in the course of infection in individuals initially
infected with HBe-positive virus or can occur ab initio (particularly in patients from
Mediterranean countries and the Far East).
Stages of infection
In patients infected with HBe-positive virus, up to four stages of chronic infection (each of
which may last for many years) may be described (Figure 7).
First stage (immune tolerance phase)
Initially (particularly in those infected in utero or at birth) there may be high levels of
viraemia without biochemical or histological evidence of hepatitis.
Treatment with interferon or nucleoside analogues during this phase, is not indicated
because therapy rarely induces HBe antigen clearance.
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Second stage (immune clearance phase)
Viraemia and HBe antigenaemia continue and there is increasing inflammatory necrosis of
hepatocytes. HBV DNA is detectable at levels between 103
and 109
genomes per ml.
As this phase continues, the inflammatory process may become sufficiently intense to permit
lysis of infected hepatocytes, clearance of HBeAg and the development of anti-HBe.
If the inflammation is sufficiently intense and prolonged, patients may develop cirrhosis.
The phenomenon of loss of HBeAg and conversion to anti-HBe positivity is referred to as ‘HBe
antigen/antibody seroconversion’. When this occurs, there is a reduction of inflammation
accompanied by histological change from active to inactive chronic hepatitis, or active
cirrhosis to inactive cirrhosis in patients in whom seroconversion has been prolonged.
The spontaneous seroconversion rate is 5–10% per year, though this varies between
populations: HBe antigen clearance is commonest in genotypes A and B.
Treatment during this phase with interferon and then, in those that do not undergo ‘HBe
antigen/antibody seroconversion’, maintenance viral suppressive therapy with nucleoside
analogues, is indicated (see below).
Third stage (immune control or latent phase) (inactive carrier)
Follows seroconversion. Patients continue to produce HBsAg because of integrated sequences
of viral DNA within host cell DNA but HBV replication is controlled by the cellular immune
response at levels <103
genomes per ml.
The liver may show mild persistent hepatitis, normal histology or cirrhosis which is inactive,
and the blood biochemistry may be normal.
Despite the lack of HbeAg and HBV-DNA being present at only very low levels by the PCR, the
patient's body fluids should still be considered infectious.
Fourth stage (HBe negative viraemia/hepatitis phase)
Further viraemia and hepatitis in the absence of HBe antigenaemia may follow, reflecting
emergence of the HBe-negative (pre-core or core promoter mutant) strain of the virus.
During this stage, transaminases become elevated and HBV DNA is detectable by PCR at
concentrations of >103
genomes per ml, but HBeAg is not present in the serum.
Continuing hepatitis in this phase may lead to cirrhosis.
Treatment during this phase with interferon and then, in those who do not show sustained
control of viraemia and resolution of hepatitis, maintenance viral suppressive therapy with
nucleoside analogues, is indicated (see later).
Prognosis, in terms of the potential to develop cirrhosis and HCC, is greatest in those with
the highest viraemia levels.
Clinical features
The severity of the hepatitis in both transient and persistent infections is variable depending
on the nature of the host response.
Acute HBV infection
The incubation period is 3–6 months.
In the week before icterus appears, some patients develop a serum sickness-like syndrome
including arthralgia, fever and urticaria.
The clinical picture varies from asymptomatic anicteric infection to protracted icterus and,
in some patients (<1%), liver failure (fulminant hepatitis).
The severity of the hepatitis increases with age.
The acute infection is self-limiting and does not need antiviral therapy. Most patients
recover within 1–2 months after the onset of icterus.
Patients who are symptomatic may require bed-rest but this probably does not accelerate
recovery.
Sexual contacts should be offered hyperimmune globulin and then immunized with the
vaccine.
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Chronic HBV infection
Chronic hepatitis B is defined as viraemia and hepatic inflammation continuing for more than
6 months following HBV infection.
Most patients acquire the infection at birth or after a subclinical infection as an adult, so are
unaware that they have been infected by the virus.
Table 15. Clinical and immunological features favoring persistent hepatitis B virus infection
• Neonatal exposure
• In adults – male gender, hypogammaglobulinaemia and cell‐mediated immune deficiencies
Possible pathogenic mechanisms
• Production of subnormal quantities of interferon‐α by peripheral blood cells
• Poor hepatocyte activation by interferon
• Failure of antibody production
• Failure to develop HBV‐specific cytotoxic T cells
Patients with chronic hepatitis are often asymptomatic, though they may suffer from malaise,
and well-compensated cirrhosis can be asymptomatic.
Presenting features
Incidental presentation – patients are most commonly asymptomatic and are recognized
following blood donation, or blood or other routine medical screening.
Following symptomatic HBV infection – symptoms include general malaise, fatigue,
arthralgia and right hypochondrial discomfort.
At later stages, patients may present with hepatic decompensation or during acute flares of hepatitis.
After an episode of acute HBV infection, patients should be followed up until HBsAg
disappears, anti-HBs appears and liver function tests become normal. If this does not occur
within 6 months, the patient is chronically infected with HBV.
Negative IgM antibody to hepatitis B core antigen (HBcAg) at presentation suggests a patient
is not in an episode of acute hepatitis, but already has chronic HBV infection.
Complications
Cirrhosis with its complications.
Hepatocellular carcinoma is common in regions with a high prevalence of hepatitis B
infection. The risk of HCC in an HBsAg-positive male in the Far East is almost 300 times
greater than that in HBsAg-negative controls.
Extrahepatic manifestations, caused by immune complexes (look later).
Management
Treatment of Acute Hepatitis B
Most cases of acute HBV infection are asymptomatic.
Symptomatic cases require mainly supportive treatment including intravenous fluids,
antiemetics, and reassurance.
In the more rare case of fulminant hepatic failure due to HBV, treatment will be require
intensive care units monitoring at a medical center with a liver transplant program.
All patients identified as having acute HBV should be educated about the disease and the
risk they pose in possibly transmitting this infection to other people. They should be
counseled on using barrier protection during sexual intercourse for at least a number of
months following infection and until recovery is documented.
Contacts of infected individuals should be identified and contacted. Non-vaccinated close
contacts of the individual should be offered post-exposure prophylaxis in the form of
hepatitis B immunoglobulin (HBiG). All contacts should be offered vaccination against HBV.
After the initial diagnosis of acute HBV, individuals should be monitored for loss of HBsAg
and the development of HBsAb to document recovery or the persistence of HBsAg/HBeAg to
document development of chronic infection.
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Treatment of Chronic Hepatitis B
The aims of treatment of chronic hepatitis B are:
Symptomatic improvement
Normalization of serum ALT level
Undetectable serum HBV DNA by an unamplified assay
Seroconversion from HBeAg positivity to anti-HBe positivity
Improvement in liver histology
Prevention of long-term complications
Reduction in mortality
Responses to antiviral therapy of chronic HBV is categorized as biochemical (BR),
virologic (VR), or histologic (HR), and as on-therapy or sustained off-therapy (Table 16).
Table 16 Definition of response to antiviral therapy of chronic HBV
Category of response
Biochemical (BR) Decrease in serum ALT to within the normal range
Virological (VR) Decrease in serum HBV DNA to undetectable levels in unamplified assays (<105
copies/ml), and
loss of HBeAg in patients who were initially HBeAg positive
Histological (HR) Decrease in histology activity index by at least 2 points compared to pre‐treatment liver biopsy
Complete (CR) Fulfill criteria of biochemical and virological response and loss of HBsAg
Time of assessment
On-therapy During therapy
Maintained Persist throughout the course of treatment
End‐of‐treatment At the end of a defined course of therapy
Off-therapy After discontinuation of therapy
Sustained (SR‐6) 6 months after discontinuation of therapy
Sustained (SR‐12) 12 months after discontinuation of therapy
Indications for therapy
Persistently positive HBsAg (for >6 months)
HBV DNA level >2000 IU/ml (≈ 104 copies/mL) (IU = 5 copies)
ALT level greater than the normal limit
Liver biopsy showing necroinflammatory injury (moderate to severe, i.e. at least A2F2)
The following special groups of patients should not be treated:
Immunotolerant patients: most patients under 30 years of age with persistently normal ALT levels and a
high HBV DNA level (usually above 107
IU/ml), without any suspicion of liver disease and without a family
history of HCC or cirrhosis do not require immediate liver biopsy or therapy. Follow up is mandatory.
Patients with mild CHB: patients with slightly elevated ALT (less than 2 times ULN) and mild histological
lesions (less than A2F2 with METAVIR scoring) may not require therapy. Follow-up is mandatory.
Patients should be educated about their infectivity and their contacts should be notified to
receive HBV vaccination and possibly HBIG, if not previously vaccinated.
Patients should be offered immunization against HAV if they are not already immune and
they should avoid alcohol in order to minimize liver injury.
Currently there is a number of approved medications for the treatment of chronic HBV.
These include interferon alpha-2b, PegINF alpha-2a, lamivudine, adefovir, entecavir
and telbivudine.
Predictors of good response
Low viral load (HBV DNA below 107
IU/ml) pretreatment
High serum ALT levels (above 3 times ULN)
High activity scores on liver biopsy (at least A2)
HBV DNA decrease to < 20,000 IU/ml at 12 weeks during treatment
HBeAg decrease at week 24
HBV genotype A and B have better response to INF than genotypes C and D
