Metabolic acidosis
LIFE-THREATENING DISORDERA physiologic state of excess acid accumulation and deficient base bicarbonate, metabolic acidosis is produced by an underlying pathologic disorder. Symptoms result from the body’s attempts to correct the acidotic condition through compensatory mechanisms in the lungs, kidneys, and cells.
Metabolic acidosis is more prevalent among children, who are vulnerable to acid-base imbalance because their metabolic rates are faster and their ratios of water to total body weight are lower. Severe or untreated metabolic acidosis can be fatal.
Causes
Metabolic acidosis usually results from excessive burning of fats in the absence of usable carbohydrates. This can be caused by diabetic ketoacidosis, chronic alcoholism, malnutrition, or a low-carbohydrate, high-fat diet—all of which produce more keto acids than the metabolic process can handle.
Other causes include:
anaerobic carbohydrate metabolism: a decrease in tissue oxygenation or perfusion, as occurs with pump failure after myocardial infarction, or when pulmonary or hepatic disease, shock, or anemia forces a shift from aerobic to anaerobic metabolism, causing a corresponding rise in the lactic acid level
renal insufficiency and failure (renal acidosis): underexcretion of metabolized acids or the inability to conserve base
diarrhea and intestinal malabsorption: loss of sodium bicarbonate from the intestines, causing the bicarbonate buffer system to shift to the acidic side. For example, ureteroenterostomy and Crohn’s disease can also induce metabolic acidosis.
Less frequently, metabolic acidosis results from salicylate intoxication (overuse of aspirin), exogenous poisoning, or Addison’s disease with an increased excretion of sodium and chloride and the retention of potassium ions (due to a deficiency of glucocorticoids and mineralocorticoids).
