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Liver:
Liver disease
associated with the excess consumption of alcoholic beverages has been
recognized for several thousand years, having been implied in the Ayurveda,
the ancient medical text of India.
Almost 300 years ago the noted English
clinician, Thomas Heberden, wrote about the increase in "scirrhous" livers
in those who consume large quantities of "spirituous liquors".
Alcoholic liver disease, the most common medical complication of
alcoholism, accounts for majority of the cases of cirrhosis of the liver
in the industrialized countries. (In Asia and Africa, by contrast, most
cirrhosis is due to infection with the Hepatitis B virus).
The nature of the alcoholic beverage is largely irrelevant, only the total
daily dose of alcohol is relevant.
Alcoholic liver disease is conventionally divided into three major phases:
- a reversible
fatty liver , which has few functional consequences ;
- alcoholic
hepatitis, an inflammatory and necrotizing disease of the liver. Which
has a significant mortality ; and
- cirrhosis, an
irreversible scarring of the liver. This leads
to liver failure or the consequences of portal hypertension, particularly
gastrointestinal hemorrhage.
Pancreas:
The relationship
of acute pancreatitis to alcoholism is unclear, but such episodes are seen
with sufficient frequency to suggest that it is also a complication of
alcoholism.
Chronic calcifying pancreatitis is a result of alcoholism, and is an important cause of
incapacitating pain, pancreatic insufficiency, and pancreatic stones.
Among men in the industrialized countries alcoholism may be the cause of
the majority of cases of chronic pancreatitis.
Heart:
Alcohol-related
heart disease was recognized over a century ago in Germany, where it was
referred to as the "beer-drinker’s heart" .
This degenerative disease of
the myocardium, termed alcoholic cardiomyopathy, leads to low-output
congestive heart failure.
Although the pathogenesis is obscure, it is
widely accepted as a toxic effect of ethanol.
This cardiomyopathy is
clearly different from the heart disease associated with the thiamine
deficiency (beri-beri), a disorder characterized by high-output failure.
Cardiac changes in alcoholics are far more common than are usually
appreciated.
Upto 20% of confirmed alcoholics may show ultrastructural
changes in the myocardium on endomyocardial biopsy.
The alcoholic heart
seems also to be more susceptible to arrhythmias, and the occurrence of
abnormal cardiac rhythms after an alcoholic binge has been termed the
"holiday heart".
Many cases of sudden death in alcoholics are probably
caused by sudden, fatal arrhythmias.
Skeletal Muscles:
Muscle weakness
is extremely common in alcoholics and is often attributed to general
debility of nutritional deficiency.
However, when carefully tested
clinically, even well-nourished alcoholics usually show some weakness,
particularly of the proximal muscles.
A wide range of changes in skeletal
muscle is seen in chronic alcoholics, varying from mild alterations in
muscle fibers evident only by electron microscopy to a severe,
debilitating chronic myopathy, with degeneration of muscle fibers and
diffuse fibrosis.
On rare occasions, acute alcoholic rhabdomyolysis
- acute
necrosis of muscle fibers and release of myoglobin to the circulation - is
seen. This sudden event can be fatal, because of renal failure secondary
to myoglobulinurea.
Endocrine system:
The principal
endocrine effect of alcoholism in men is on the testes, which are reduced
in size.
Feminization of chronic alcoholics, together with loss of libido
and potency, is common.
The distribution of fat may change, giving the
alcoholic male a female habitus. The breasts become enlarged (gynecomastia),
body hair is lost and a female distribution of pubic hair develops.
Some of these changes can be attributed to an impaired
metabolism of estrogens due to chronic liver disease, but many of the
changes - particularly atrophy of the testes - occur in the absence of any
liver disease.
Chronic alcoholism leads to lower levels of circulating
testosterone because of a complex interference with the pituitary-gonadal
axis, possibly complicated by an accelerated metabolism of testosterone by
the liver.
Gastrointestinal Tract:
A direct toxic effect on the mucosa of the esophagus and stomach is
common.
Injury to the mucosa of both organs is potentiated by the
hypersecretion of gastric hydrochloric acid stimulated by ethanol.
Reflux esophagitis may be particularly painful, and peptic ulcers are also more
common in the alcoholic.
Violent retching may lead to tears at the
esophageal-gastric junction (Mallory-Weiss syndrome), sometimes so severe
as to result in exsanguinating hemorrhage.
The mucosal cells of the small
intestine are also exposed to circulating alcohol, and a variety of
absorptive abnormalities and ultrastructural changes have been
demonstrated.
Alcohol inhibits the active transport of amino acids, thiamine, and
vitamin B12.
Blood:
Megaloblastic
anemia secondary to a deficiency of folic acid is not uncommon in
malnourished alcoholics.
A nutritional deficiency of folic acid is the
most important factor, but alcohol is itself considered a weak folic acid
antagonist in man.
Moreover, absorption of folate
in the small intestine may be decreased in alcoholics.
In addition, chronic ethanol intoxication leads directly to an increase in
red blood cell volume.
In the presence of
alcoholic cirrhosis the spleen is often enlarged by portal hypertension.
In such cases hypersplenism often causes hemolytic anemia.
Acute transient thrombocytopenia is
common after acute alcohol intoxication and may result in bleeding.
Alcohol also interferes with the aggregation of platelets, thereby
contributing to bleeding.
Immune System:
No consistent effect of alcohol on humoral or
cell-mediated immunity has yet been conclusively established.
Neither is
there convincing evidence of an alcohol-related defect in neutrophils.
Clinically, however, alcoholics seem to be prone to many
infections - particularly pneumonias - with organisms that are unusual in the
general population, such as Haemophilus influenzae.
Brain:
A general
cortical atrophy of the brain is common in alcoholics and may reflect a
toxic effect of alcohol.
By contrast, most of the characteristic brain
diseases in alcoholics are probably a result of nutritional deficiency.
Wernicke's encephalopathy, caused by thiamine deficiency, is characterized
by mental confusion, ataxia, abnormal ocular motility, and polyneuropathy.
The pathologic changes involve the diencephalons and brain stem.
Lesions
are always present in the mammillary bodies and are frequently present in
the walls of the third ventricle and the periaqueductal gray matter.
Necrosis of nerve cells and myelinated fibers, together with glial
responses, are noted.
The retrograde amnesia and symptoms of Korsakoff's psychosis, once thought
to be pathognomonic of chronic alcoholism, have now been identified in a
number of organic mental syndromes and are considered nonspecific.
Alcoholic cerebellar degeneration is differentiated from other forms of
acquired or familial cerebellar degeneration by the uniformity of its
manifestations.
Progressive unsteadiness of gait, ataxia, incoordination,
and reduced deep tendon reflex activity are present.
The cerebellar vermis
displays varying degrees of shrinkage of the folia and widening of the
sulci.
At the microscopic level, the Purkinje cells are the neuronal elements
primarily destroyed, but in advanced cases the molecular and granular cell
layers are also affected.
Central pontine
myelinolysis is another characteristic change in the brain of alcoholics,
apparently caused by electrolytic imbalance - usually after electrolyte
therapy, after an alcoholic binge, or during withdrawal.
In this
complication a progressive weakness of bulbar muscles causes dysphagia
and dysarthria and may be rapidly succeeded by an inability to swallow.
Quadriparesis and coma eventually terminate in respiratory paralysis.
Microscopic examination reveals foci of demyelination in pons.
Amblyopia
(impaired vision) is occasionally seen in alcoholics and may result from
an alcohol-related decrease in tissue vitamin A, although other vitamin
deficiencies may also be involved.
Alcohol and
Cancer;
The incidence
of cancer of the lung, upper respiratory tract, and esophagus is
greater in alcoholics than in the general population, but
the precise relationship of cancer to alcohol consumption is confused by
the fact that most alcoholics are also smokers.
Environmental Pathology- Alcoholism (Mechanism of
Tissue Injury): click here
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