Liver abscess

liver Abscess
By Dr Mengistu.K

Pyogenic Liver Abscess
• Pyogenic liver abscesses are the most common
liver abscesses seen in the United States.
• Previously they were felt to be due to portal
infection, often occurring in young patients
secondary to acute appendicitis.
• Pyogenic liver abscess is now mostly seen in
patients 50 to 60 years old and is more often
related to biliary tract disease or is cryptogenic.
7/30/2016 Dr.mengistu 2

Pathogenesis
• The development of a hepatic abscess occurs
when an inoculum of bacteria, regardless of
the route of exposure, exceeds the liver’s
ability to clear it.
• This results in tissue invasion, neutrophil
infiltration, and formation of an organized
abscess.

• Six distinct categories have been identified as
potential sources:
– Bile ducts, causing ascending cholangitis
– Portal vein, causing pylephlebitis from appendicitis
or diverticulitis
– Direct extension from a contiguous disease ( e.g
gangrenous cholecystitis, perforated ulcers, and
subphrenic abscesses)
– Trauma due to blunt or penetrating injuries
– Hepatic artery, due to septicemia; and
– Cryptogenic

• Disease of the biliary system accounts for 35–
40% of all pyogenic liver abscesses, and 40%
related to an underlying malignancy.
• Intestinal pathology is responsible for 20% of
all pyogenic liver abscesses. Diverticulitis,
perforated colon cancers are being the most
common causes and appendicitis accounts for
only 2%.

• Arterial embolization of bacteria via the
hepatic artery causes approximately 12% of
pyogenic liver abscesses.
• Cryptogenic abscesses, those of unknown
etiology, occur in 10–45% of patients.
• Hepatic abscesses associated with trauma can
be manifested in a delayed fashion up to
several weeks after injury.

Predisposing Factors

Pathology
• Involve the right hemiliver in 75% of cases due to
preferential laminar blood flow to the right side has been
postulated.
• The left liver is involved in approximately 20% of the
cases; the caudate lobe is rarely involved (5%).
• Bilobar involvement with multiple abscesses is
uncommon.
• Approximately 50% of hepatic abscesses are solitary.
• Vary in size from less than 1 mm to 3 or 4 cm in diameter.
when multiple, may coalesce to give a honeycomb
appearance.

• In general, portal, traumatic, and cryptogenic
hepatic abscesses are solitary and large, while
biliary and arterial abscesses are multiple and
small.
• Fungal abscesses are usually multiple,
bilateral, and miliary

Bacteriology
• The most common infecting agents are gram
negative organisms. Escherichia coli is found in two
thirds, and Streptococcus faecalis, Klebsiella, and
Proteus vulgaris are also common.
• Anaerobic organisms such as Bacteroides fragilis are
also seen frequently involved about 40% to 60% of
the time..
• Staphylococcus and Streptococcus are more common
in patients with endocarditis and infected indwelling
catheters.

• Approximately 40% of abscesses are
monomicrobial, an additional 40% are
polymicrobial, and 20% are culture negative
• Abscesses from pyelophlebitis or cholangitis
tend to be polymicrobial, with a high
preponderance of gram-negative bacilli.
• Systemic infections, on the other hand, usually
cause infection with a single organism.

Clinical Features
• The classic triad of fever, jaundice, and right upper
quadrant tenderness was present in less than 10% of
patients overall.
• On physical examination, fever and right upper quadrant
tenderness are the most common findings.
• Tenderness is present in 40% to 70% of patients.
• Jaundice is also found in approximately 25% of cases.
• Chest findings are often found in approximately 25% of
patients, and hepatomegaly is also commonly noted in
approximately 50%.

Laboratory Evaluation
• Leucocytosis in 70% to 90% of patients, an
elevated sedimentation rate, and an elevated
alkaline phosphatase (AP) level mildly
elevated in 80% of cases are the most
common laboratory findings.
• Abscess cultures are positive for growth in the
majority (80–97%), whereas blood cultures
are positive in only 50–60% of cases.

Radiology
• Chest radiographs
– Abnormal in 50% of patients.
– Findings may include an elevated right
hemidiaphragm, a right pleural effusion, and/or
right lower lobe atelectasis.
• Abdominal films may show
– Hepatomegaly
– Air-fluid levels in the presence of gas-forming
organisms
– Portal venous gas if pylephlebitis is the source

• Ultrasound will distinguish
solid from cystic lesions
and is 80–95% sensitive.
• Usually demonstrates a
round or oval area that is
less echogenic than the
surrounding liver.

• Computed tomography
(CT) is more sensitive
(95–100%) than US in
detecting hepatic
abscesses.
• An abscess is of lower
attenuation than the
surrounding liver, and the
wall of the abscess may
enhance with intravenous
contrast administration.

Treatment
• The current cornerstones of treatment include
– IV antibiotic therapy
– correction of the underlying cause and
– needle aspiration,

IV antibiotic therapy
• Broad-spectrum antibiotics covering gram-
negative, gram-positive, and anaerobic
organisms should be used.
• Combinations such as ampicillin, an
aminoglycoside, and metronidazole or a third-
generation cephalosporin with metronidazole
are appropriate

• Antibiotic therapy must be continued for at least 8
weeks.
• If aspiration done IV antibiotic therapy should be
given for 4–6 weeks; however, many studies now
document success with only 2 weeks of antibiotic
therapy
• Aspiration and IV antibiotic therapy can be expected
to be effective in 80 to 90% of patients.
• In the setting of multiple abscesses <1.5 cm in size
and no concurrent surgical disease, patients may be
treated with IV antibiotics alone.

Aspiration and Percutaneous Catheter
Drainage
• Have similar mortality rates
• Recurrence rates and the requirement for
surgical intervention may be greater in those
who only undergo aspiration.
• Recurrence (15%) in patients with biliary tract
disease and obstructive lesions but less than
2% with cryptogenic abscesses.

• Percutaneous drainage is not appropriate for
those patients with
– Multiple large abscesses
– A known intra-abdominal source that requires
surgery
– An abscess of unknown etiology
– Ascites and
– Abscesses that would require transpleural
drainage

Surgical Drainage
• Extraperitoneally via a 12th-rib resection
• Transperitoneally surgical exploration
• Reserved for patients for
– Failed nonoperative therapy,
– Those who need surgical treatment of the
underlying source,
– Those with multiple macroscopic abscesses,
– Those on steroids, or those patients with
concomitant ascites

Complications
• Up to 40% of patients develop complications
from pyogenic liver abscesses
• Generalized sepsis: most common
• Pleural effusions
• Empyema, and pneumonia.
• Intraperitoneal rupture
• Hemobilia and hepatic vein thrombosis

Outcome
 Series from the 1990s have demonstrated a mortality rate below 10%.
The most recent series from Memorial Sloan Kettering Cancer Center
(MSKCC) has reported a 3% mortality.

Amebic Abscess
• Amebic abscesses are the most common type of
liver abscesses worldwide.
• Entamoeba histolytica is a parasite that is
endemic worldwide, infecting approximately
10% of the world's population.
• Amebiasis is largely a disease of tropical and
developing countries but is also a significant
problem in developed countries because of
immigration and travel between countries.

Epidemiology
• E. histolytica infections have estimated that as
many as 55% of those in endemic regions are
infected, although less than 50% are
symptomatic.
• Amebiasis follows a bimodal age distribution.
One peak is at age 2–3 years, with a case
fatality rate of 20%, and the second peak is at
>40 years, with a case fatality rate of 70%.

• Low socioeconomic status and unsanitary
conditions are significant independent risk
factors for infection.
• Amebic liver abscess is ten times as common in
men as in women and is a rare disease in
children
• Heavy alcohol consumption is commonly
reported and may render the liver more
susceptible to amebic infection.

Pathogenesis
• Hepatic amebic abscess is essentially the result of
liquefaction necrosis of the liver producing a cavity
full of blood and liquefied tissue.
• Ingestion of E. histolytica cysts through a fecal-oral
route is the cause of amebiasis.
• Once ingested, the cysts are not degraded in the
stomach and pass to the intestines, where the
trophozoite is released and passed on to the colon.
• In the colon, the trophozoite can invade mucosa,
resulting in disease.

• Amebae multiply and block small intrahepatic
portal radicles with consequent focal
infarction of hepatocytes.
• They contain a proteolytic enzyme that also
destroys liver parenchyma.

Pathology
• Invasive amebiasis can include anything from
amebic dysentery to metastatic abscesses.
• The most common form of the invasive disease
is colitis.
• The amebic abscess is most commonly located
in the superior-anterior aspect of the right lobe
of the liver near the diaphragm.

• The most common extraintestinal site of
amebiasis is the liver, occurring in 1–7% of
children and 50% of adults (usually males)
with invasive disease.
• The majority (70–80%) of patients experience
a gradual onset of symptoms with worsening
diarrhea, abdominal pain, weight loss, and
stools consisting of blood and mucus.

Clinical Features
• About 80% of patients with amebic liver abscess
present with symptoms lasting from a few days
to 4 weeks.
• The duration of symptoms has been found to be
typically less than 10 days.
• The typical clinical picture is a patient 20 to 40
years of age who has recently traveled to an
endemic area, with fever, chills, anorexia, right
upper quadrant pain and tenderness, and
hepatomegaly.

• The abdominal pain is typically constant, dull,
and localized to the right upper quadrant.
• Although some studies report higher numbers,
approximately 25% of patients have diarrhea
despite an obligatory colonic infection.
• Synchronous hepatic abscess is found in one
third of patients with active amebic colitis.

• Patients presenting acutely (symptoms <10
days) versus those with a chronic presentation
(>2 weeks) differ clinically.
• Acute presentations are typically more
dramatic, with high fevers, chills, and significant
abdominal tenderness.
• In the acute presentation, 50% of patients have
multiple lesions, whereas with the chronic
presentation, more than 80% of patients have a
single right-sided lesion.

• Laboratory abnormalities are common in
amebic abscess.
• Patients typically have a mild to moderate
leukocytosis without eosinophilia. whereas
elevated transaminase levels and jaundice are
unusual.
• The most common biochemical abnormality is
a mildly elevated AP level.

• Because more than 70% of patients with amebic
liver abscess do not have detectable amebae in
their stool, the most useful laboratory evaluation
is the measurement of circulating antiamebic
antibodies, which are present in 90% to 95% of
patients.
• The EIA has a reported sensitivity of 99% and
specificity greater than 90% in patients with
hepatic abscess.

Abdominal CT scan is probably more sensitive
than ultrasound and is helpful in differentiating
amebic from pyogenic abscess, with rim
enhancement noted in the latter.

Management
• The mainstay of treatment for amebic abscesses
is metronidazole (750 mg orally three times per
day for 10 days), which is curative in more than
90% of patients.
• Clinical improvement is usually seen within 3
days.
• The time necessary for the abscess to resolve
depends on the initial size at presentation and
varies from 30 to 300 days.

In general, aspiration is recommended for
 diagnostic uncertainty
 failure to respond to metronidazole therapy in 3
to 5 days, or
in abscesses felt to be at high risk for rupture.
NB: Abscesses larger than 5 cm in diameter and
in the left liver which has a higher risk of rupture
into the pericardium, and aspiration needs to be
considered.

• The mortality rate for all patients with amebic
liver abscess is about 5% and does not appear
to be affected by the addition of aspiration to
metronidazole therapy or chronicity of
symptoms.

Hydatid Cyst
• Hydatid disease, or echinococcosis, is a
zoonosis that occurs primarily in sheep-
grazing areas of the world.
• There are three species of Echinococcus that
cause hydatid disease. Echinococcus
granulosus is the most common, whereas E.
multilocularis and E. oligartus account for a
small number of cases.

• 70% of hydatid cysts form in the liver. A few
ova pass through the liver and are held up in
the pulmonary capillary bed or enter the
systemic circulation, forming cysts in the lung,
spleen, brain, or bones.
• Three weeks after infection, a visible hydatid
cyst develops and then slowly grows in a
spherical manner.

• A pericyst, a fibrous capsule derived from host
tissues, develops around the hydatid cyst.
• The cyst wall itself has two layers: an outer
gelatinous membrane (ectocyst) and an inner
germinal membrane (endocyst).

• The clinical presentation of a hydatid cyst is
largely asymptomatic until complications occur.
• The most common presenting symptoms are
abdominal pain, dyspepsia, and vomiting.
• The most frequent sign is hepatomegaly.
Jaundice and fever are each present in about 8%
of patients

• Ultrasound is most commonly used worldwide for
the diagnosis of echinococcosis.
• A simple hydatid cyst is well circumscribed with
budding signs on the cyst membrane and may
contain free-floating hyperechogenic hydatid sand.
• A rosette appearance is seen when daughter cysts
are present.
• Calcifications in the wall of the cyst are highly
suggestive of hydatid disease

• The treatment of hepatic hydatid cysts is
primarily surgical.
• In general, most cysts are treated, but in
elderly patients with small, asymptomatic,
densely calcified cysts, conservative
management is appropriate.

Schistosomiasis
• Hepatic schistosomiasis is usually a complication of the
intestinal disease,because emboli of schistosomiasis
ova reach the liver via the mesenteric venous system.
• Schistosomiasis has three stages of clinical
symptomatology:
– First stage: itching after the entry of cercariae
– second stage: fever, urticaria, and eosinophilia; and
– Third stage: hepatic fibrosis followed by presinusoidal
portal hypertension

• During this third phase the liver shrinks, the
spleen enlarges, and the patient may develop
complications of portal hypertension.
• Active infection is detected by stool examination.
• Serologic tests indicate past exposure without
specifics regarding timing.
• A negative serologic test result rules out
schistosomal infection.

Liver abscess

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