This guide to the effects of alcoholism on the human body may be best intended for medical students but may serve as sobering warning to anyone who consumes large amounts of alcohol.
Effects on the Pulmonary System
Alcohol inhibits ciliary activity, macrophage mobilization and surfactant production, and thus increases the patient’s chances of contracting a pulmonary infection. Alcoholics frequently have pulmonary aspiration due to central nervous system depression when intoxicated, leading to aspiration pneumonitis.
Blood flow to the lungs may be impeded in chronic alcoholics with cirrhosis of the liver who may have up to 30% of their cardiac output shunting right to left, thereby decreasing oxygenation. Also, most alcoholics abuse other drugs (including nicotine) that further increase pulmonary pathology.
Cardiac disease is the leading cause of death in connection with chronic alcohol abuse due to congestive dilated cardiomyopathy. This disease is typically preceded by a decade of ingesting 80 gm of alcohol daily. Chronic heavy drinking can cause cardiomyopathy with symptoms ranging from unexplained arrhythmias in the presence of left ventricular impairment, to heart failure with dilation of all four heart chambers and hypocontractility of heart muscle. Mural thrombi can form in the left atrium, while heart enlargement exceeding 25% can cause mitral regurgitation. There is also an association between
cerebrovascular accidents and alcoholism, especially within 24 hours of heavy drinking. Atrial or ventricular arrhythmias, particularly paroxysmal tachycardia, can occur after binge drinking in patients with no known heart disease. This is known as the “Holiday Heart Syndrome”.
Alcoholic patients without overt cardiac failure may exhibit reduced diastolic compliance leading to elevated end diastolic pressure and diminished end diastolic volume. In these cases, contractility and relaxation indices are impaired. Subclinical changes may be reversible with abstinence. Evidence of right heart failure is common in alcoholic patients as is secondary pulmonary hypertension. Chronic consumption of alcohol is also associated with an elevation of blood pressure, although the mechanism for this hypertension is not clear.
Conduction defects and rhythm disturbances are often seen in chronic alcoholics. These patients may have a normal rhythm during abstinence, but develop dysrhythmias after acute consumption of alcohol. Atrial fibrillation is the most common arrhythmia. There is a high incidence of sudden death in alcohol abusers, which is thought to be due to ventricular fibrillation.
The alcoholic’s cardiac status is a prime factor in such a patient’s preoperative assessment and management. It is crucial to monitor for, and treat tachycardia, cardiomegaly and arrhythmias.
Acute effects of alcohol on blood circulation are minor. With moderate amounts of alcohol there is little change in the blood pressure, cardiac output or force of myocardial contraction. However, vasodilation, which results in a warm, flushed skin does occur. Acute, severe alcoholic intoxication causes cardiovascular depression due to central vasomotor effects and respiratory depression.
Acute alcohol intake can result in inflammation of the esophagus and stomach. The resulting esophagitis and gastritis are the most frequent causes of gastrointestinal bleeding in heavy drinkers. Violent vomiting may result in a mucosal tear, called a Mallory Weiss lesion, at the gastroesophageal junction. Esophageal varices can result secondary to cirrhosis induced portal hypertension. Also, alcohol can cause irreversible atrophy of the gastric parietal cells that secrete intrinsic factor, which is required for the absorption of vitamin B12 from the ileum. Loss of these cells may ultimately result in pernicious anemia. In addition, bleeding hemorrhagic lesions of the duodenum result in diarrhea and decreased
absorption of water and electrolytes.
Alcoholics commonly develop acute or chronic pancratitis. Further, the risk of cancer (particularly cancers of the esophagus, stomach, liver, and pancreas) is greater in these patients.
Effects on the Kidneys
Alcohol exerts a diuretic effect by inhibiting the secretion of antidiuretic hormone. The diuretic effect is proportional to the blood alcohol concentration and occurs only when the concentration is rising. When the blood alcohol concentration is falling, it acts as an antidiuretic.
Serum sodium may be slightly increased and potassium decreased in chronic alcoholics. These patients also have increased total body water. Further, hypomagnesemia may be present, especially during withdrawal.
Effects on the Endocrine System
Chronic alcohol abuse may cause gynecomastia, testicular atrophy and irregular menses. Cortisol levels are elevated during heavy drinking. Vasopressin secretion is decreased with rising blood alcohol concentrations and decreased with falling blood alcohol concentrations. This results in most alcoholics being slightly overhydrated.
Chronic alcohol use alters the production of red blood cells. An increase in RBC size is most often seen without an anemia, due to the effect of alcohol on stem cells. If the patient has a folic acid deficiency, there will often be reticulocytopenia.
A decreased production of white blood cells is seen, as is decreased granulocyte mobility. This results in an increased risk of infection. A delayed hypersensitility response to new antigens may appear, potentially resulting in a false negative result from TB skin testing.
Many alcoholics present with mild thrombocytopenia due to a decrease in platelet survival and altered function. Hypersplenism resulting in thrombocytopenia may also be seen with cirrhosis. In addition, alcohol may decrease platelet aggregation and inhibit the release of thromboxane A2, which is required for clotting. These changes normalize with a week of abstinence.
Alcohol can produce an alcoholic myopathy characterized by painful and swollen muscles. Altered calcium metabolism can cause osteoporosis with a resulting increased risk of fracture.