Starvation metabolic acidosis

Metabolic acidosis (starvation, ketoacidosis, alcoholism) Renal diseases... 

Hyperkalemia may occur in renal disease and adrenal insufficiency owing to impairment of normal secretory mechanisms. Metabolic acidosis, in particular diabetic acidosis, and catabolism of cellular protein in starvation or fever cause K+ release from cells. Treatment consists of correction of the acidosis and promotion of cellular uptake of K+ by administration of insulin, which enhances glucose intake. In severe cases, ion exchange resins given orally bind K+ in intestinal secretions. 

Metabolic acidosis with an increased SAG commonly results from increased endogenous organic acid production. In lactic acidosis, lactic acid accumulates as a by-product of anaerobic metabolism. Accumulation of the ketoacids /S-hydroxybutyric acid and acetoacetic acid defines the ketoacidosis of uncontrolled diabetes mellitus, alcohol intoxication, and starvation (see Table 51-5). In advanced renal failure, ac-cumulation of phosphate, sulfate, and organic anions is responsible for the increased SAG, which is usually less than 24 mEq/L." The severe metabolic acidosis seen in myoglobinuric acute renal failure caused by rhabdomyolysis may be caused by the metabolism of large amounts of sulfur-containing amino acids released from myoglobin. 

High anion gap metabolic acidosis may develop in many clinical settings, inclnding nncontrolled diabetes meUitns (see Chap. 72), alcohol intoxication (see Chaps. 37 and 65), and starvation (see Chap. 62). Toxic ingestions of methanol, ethylene glycol, and salicylates are also associated with high anion gap metabolic acidosis (see Chap. 10). The mechanisms responsible for the development of acidosis in these settings are diverse. 

If there is insufficient bicarbonate to compensate for the extra acid, acidosis can occur. Formally, acidosis is a significant decrease in pH of extracellular fluid. This condition can occur due to both respiratory and metabolic abnormalities. Respiratory acidosis occurs when breathing abnormalities result in CO2 retention and an elevation in Pco2 in alveoli and arterial blood (known as hypercapnia). The term Pco2 refers to the partial pressure of CO2 in the pulmonary alveoli during respiration. Retention of CO2 can result from inadequate ventilation during anesthesia, certain conditions that result from central nervous system disease, or from drug use, and it is observed with emphysema. Metabolic acidosis occurs with starvation, uncontrolled diabetes mellitus with ketosis, and with electrolyte and water loss due to diarrhea.il... 

Even though ketone bodies can be used by various extrahepatic tissues, during starvation the liver may produce them in such large quantities that the metabolic capacity of these tissues is exceeded. If this is so, ketone bodies accumulate in the blood with consequent ketosis and metabolic acidosis. 

During starvation, body fats replace dietary carbohydrates as a major source of energy. Metabolism of these fats yields organic acids such as acetoacetic acid. This causes a mild metabolic acidosis. In strenuous exercise, particularly in a trained athlete, fats are preferentially metabolized also, in exercise sufliciently strenuous to exceed the anaerobic threshold, lactic acid is released into the extracellular fluid in all subjects, both the trained athlete and the normal person. Fever and trauma such as extensive bums or major surgery result in tissue breakdown this catabolism results in the release of organic acids into the extracellular fluid. 

Oral Treatment of hypokalemia in the following conditions With or without metabolic alkalosis digitalis intoxication familial periodic paralysis diabetic acidosis diarrhea and vomiting surgical conditions accompanied by nitrogen loss, vomiting, suction drainage, diarrhea, and increased urinary excretion of potassium certain cases of uremia hyperadrenalism starvation and debilitation corticosteroid or diuretic therapy. 

Conditions that result in increased production of metabolic acids include lactic acidosis and diabetic ketoacidosis. Lactic acidosis occurs with anaerobic metaboUsm in the presence of severe hypoxemia (i.e., Pao < 36 mm Hg). Any condition that prevents adequate oxygenation resulting in hypoxemia, such as respiratory failure or lung cancer, as well as any condition causing a decrease in perfusion to body tissues, such as heart failure or shock of any form, will result in anaerobic metabolism and lactic acid buildup. In diabetic ketoacidosis, the lack of insulin to move glucose into the cells results in a form of starvation and the production and accumulation of ketoacids (i.e., ketosis) owing to the use of lipids for fuel. 

Shifting the metabolic machinery of the body to excessive utilization of fats instead of carbohydrates or a balance of fats and carbohydrates results In the buildup of ketone bodies— acetoacetate, beta-hydroxybutyrate, and acetone—in the blood and their appearance in the urine. This condition is referred to as ketosis, and outwardly noted by the sweetish, acetone odor of the breath. Three circumstances can cause ketosis (1) high dietary intake of fat but low carbohydrate intake as in ketogenic diets (2) diminished carbohydrate breakdown and high mobilization of fats as in starvation or (3) disorders in carbohydrate metabolism as in diabetes melli-tus. Unless ketosis goes unchecked and results in acidosis, it is a normal metabolic adjustment. 

Ketosis— The most common causes of this condition— which is characterized by an excess of ketones in the blood— are (1) diabetes (2) diets high in fat and protein, but low in carbohydrate (3) fevers and (4) starvation. A mild ketosis in normally healthy people is usually not dangerous, unless it occurs regularly over a long period of time, flien, it may lead to such problems as (1) excessive urinary loss of sodium and water (2) acidosis which provokes the loss of calcium from bone, and potassium from muscle and (3) the accumulation of uric acid (a waste product of protein metabolism) in the blood, and sometimes in the soft tissues where it causes damage and pain (the latter disorder is commonly called gout). Uric acid buildup is usually treated with alkalizers to prevent the formation of kidney stones. However, the alkalizers may cause other alterations in mineral metabolism. 

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