ethanol is oxidized to acetaldehyde mainly via the hepatic enzyme alcohol dehydrogenase IB (class I), beta polypeptide (ADH1B).Alcohol dehydrogenase: The name "alcohol dehydrogenase" sounds like quite a mouthful, but it is quite self-explanatory if we break it down into its component parts. "de-" is a prefix which means "to remove". We find it in such words as "dethrone" which means "to remove from the throne". "-ase" is a suffix which means "enzyme". Any time you see a chemical term which ends in the suffix "-ase" you know that you are dealing with an enzyme. "hydrogen" means "hydrogen" of course. So "de-hydrogen-ase" means "an enzyme which removes hydrogen atoms", and "alcohol dehydrogenase" means "an enzyme which removes hydrogen atoms from the alcohol molecule". The name alcohol dehydrogenase is sometimes abbreviated to ADH.The acetaldehyde released into the brain by the metabolism of alcohol by catalase has the potential to combine with neurotransmitters to form new compounds known as THIQs (tetrahydroisoquinolines, also sometimes called TIQs). Some researchers believe that THIQs are the cause of alcohol addiction and that the presence of THIQs distinguishes addicted drinkers from social drinkers.Acetaldehyde is a highly unstable compound and quickly forms free radical structures which are highly toxic if not quenched by antioxidants such as ascorbic acid (Vitamin C) and Vitamin B1 (thiamine). These free radicals can result in damage to embryonic neural crest cells and can lead to severe birth defects. Prolonged exposure of the kidney and liver to these compounds in chronic alcoholics can lead to severe damage.Acetaldehyde dehydrogenase does its work in the mitochondria of cells and removes a hydrogen atom from acetaldehyde to produce an acetic acid radical. This hydrogen atom combines with NAD+ to form NADH. This excess of NADH can lead to acidosis from lactic acid build-up and hypoglycemia from lack of glucose synthesis.The [NAD+]/[NADH] ratio in the cytosol of cells is a major regulatory mechanism. As the [NADH] increases, the ratio decreases.The citric acid cycle itself was finally identified in 1937 by Hans Adolf Krebs while at the University of Sheffield, for which he received the Nobel Prize for Physiology or Medicine in 1953
A thorough history of alcohol use should be obtained. The CAGE questionnaire is a useful screening method for alcohol abuse or dependency.A detailed physical examination should be done, searching for signs of chronic liver disease and staging its severity.A liver chemistry profile (including serum albumin, bilirubin and transaminases [AST/ALT]). A complete blood count and prothrombin time or INR should be obtained.It may be necessary to perform a liver biopsy in patients with suspected alcoholic liver disease when the diagnosis is unclear because of atypical features or possible concomitant disease.
An introduction to alcoholic liver disease part 2
Alcoholic Liver disease: an
introduction part 2
Pratap Sagar Tiwari, Lecturer, NGMC
Alcohol & Liver
Making a diagnosis
Alcoholic liver disease
liver dysfunction because of Alcohol
Functions that are affected..
• Clotting factors
CHO /protein/ lipid
Storage of Vitamins
• Any pathological conditions of liver as a result
of chronic and excessive alcohol consumption
leading to a spectrum of conditions from
ranging from asymptomatic fatty liver to
alcoholic hepatitis to end-stage liver failure
• The pathology of alcoholic liver disease
consists of three major lesions, with the injury
rarely existing in a pure form:
(1) fatty liver,
(2) alcoholic hepatitis,
Diagnosis of alcoholic liver disease
1. A thorough history of alcohol use.
2. CAGE:screening method for alcohol abuse or
3. A detailed P/E should be done, searching for
signs of CLD and staging its severity.
4. A liver chemistry profile (including serum
albumin, bilirubin and transaminases [AST/ALT]).
CBC & PT/INR.
5. It may be necessary to perform a liver biopsy in
patients with suspected alcoholic liver disease
when the diagnosis is unclear .
• Have you felt the need to Cut down drinking?
• Have you ever felt Annoyed by criticism of
• Have you had Guilty feelings about drinking?
• Do you ever take a morning Eye opener ?
• Fatty liver, also known as fatty liver disease (FLD), is a
large vacuoles of triglyceride fat accumulate in liver
cells via the process of steatosis (i.e., abnormal
retention of lipids within a cell).
• AFL(steatosis) is rarely diagnosed clinically because
most patients are asymptomatic.
• The only complaint may be mild, tender
• DX: in pt with alcohol abuse/dependent with fatty
changes in imaging and excluding other causes. LFT
may be normal/mild abnormal.
ALD: Alcoholic hepatitis
• The characteristic clinical features of alcoholic
fever, hepatomegaly, jaundice, and anorexia.
• Patients can also present with right upper
quadrant/epigastric pain, hepatic
encephalopathy, and bleeding.
ALCOHOLIC CIRRHOSIS AND FIBROSIS
• The term "fibrosis" in this setting denotes the
accumulation of scar or extracellular matrix
(ECM), and is potentially reversible in the
absence of continued alcohol abuse.
• In contrast, true cirrhosis is characterized by
the presence of regenerative nodules and is
irreversible even in the absence of further
Acute liver failure
• Acute liver failure is an uncommon condition
in which the rapid deterioration of liver
function results in coagulopathy and
(encephalopathy) of a previously healthy
Liver failure: definitions
• Acute liver failure is a broad term that encompasses
both fulminant hepatic failure and subfulminant
hepatic failure (or late-onset hepatic failure).
• Fulminant hepatic failure is generally used to describe
the development of encephalopathy within 8 weeks of
the onset of symptoms in a patient with a previously
• Subfulminant hepatic failure is reserved for patients
with liver disease for up to 26 weeks before the
development of hepatic encephalopathy.