Metabolic acidosis/alkalosis

The use of CA inhibitors as diuretics is limited by their propensity to cause metabolic acidosis and hypokalemia. Their use can be indicated in patients with metabolic alkalosis and secondary hyperaldosteronism resulting for example from aggressive use of loop diuretics. Furthermore, CA inhibitors are effective dtugs to produce a relatively alkaline urine for the treatment of cysteine and uric acid stones as well as for the accelerated excretion of salicylates. Perhaps the most common use of CA inhibitors is in the treatment of glaucoma. 

Administration of protein substrates (amino acids) may result in nausea, fever, flushing of the skin, metabolic acidosis or alkalosis, and decreased phosphorus and calcium blood levels. 

Excretion into urine of ammonia produced by renal mbu-lar cells facilitates cation conservation and regulation of acid-base balance. Ammonia production from intracellular renal amino acids, especially glutamine, increases in metabolic acidosis and decreases in metabolic alkalosis. 

Monitor serum electrolytes and arterial blood gases regularly. Correct metabolic acidosis slowly to prevent the development of metabolic alkalosis or other electrolyte abnormalities. 

Metabolic acidosis and alkalosis result from primary disturbances in the serum H CO., concentration. Respiratory compensation of metabolic disturbances begins within minutes and is complete within 12 hours. 

This patient had ingested a large quantity of aspirin resulting in the classic findings of a salicylate overdose a centrally mediated respiratory alkalosis with a concurrent anion gap metabolic acidosis. 

Acid-base disturbances associated with PN usually are related to the patient s underlying condition(s). However, acid-base abnormalities may develop as a result of changes in chloride or acetate concentrations in PN admixtures. Because acetate is converted to bicarbonate in the body, excessive acetate salts in PN can lead to metabolic alkalosis excessive chloride salts in PN can lead to metabolic acidosis. PN should not be used to... 

Acidosis pH < 7.4 Alkalosis pH > 7.4 Respiratory acidosis pC02 Respiratory alkalosis pC021 Metabolic acidosis [HCO 3] Metabolic alkalosis [HCO 3] ... 

Respiratory alkalosis pC02 [H+] 4 [HCO3] 4 Metabolic acidosis... 

Metabolic acidosis [HCO3] 4 [H+] t pC02 4 Respiratory alkalosis... 

Salicylate or aspirin overdose is characterized by tinnitus, confusion, rapid pulse rate, and increased respiration. The decreased partial pressure of arterial C02 (Pco2) plus increased fixed acids first cause alkalosis, which is followed by metabolic acidosis, dehydration, and loss of fixed bases. The picture may resemble diabetic acidosis, but the history of salicylate ingestion and blood salicylate levels above. 540 mg/100 mL clinch the diagnosis. 

Metabolic acidosis is characterized by decreased plasma bicarbonate concentrations (HC03 ), whereas metabolic alkalosis is characterized by increased HC03T... 

Failure of compensation is responsible for mixed acid-base disorders such as respiratory acidosis and metabolic acidosis, or respiratory alkalosis and metabolic alkalosis. In contrast, excess compensation is responsible for metabolic acidosis and respiratory alkalosis, or metabolic alkalosis and respiratory acidosis. 

Mixed metabolic acidosis and respiratory alkalosis occur in patients with advanced liver disease, salicylate intoxication, and pulmonary-renal syndromes. 

Treatment of mixed metabolic acidosis and respiratory alkalosis should be directed at the underlying cause. 

Respiratory alkalosis pCOai [H+] i [HCO3] i Metabolic acidosis... 

Ammonia can diffuse freely into the urine through the tubule membrane, while the ammonium ions that are formed in the urine are charged and can no longer return to the cell. Acidic urine therefore promotes ammonia excretion, which is normally 30-50 mmol per day. In metabolic acidosis (e.g., during fasting or in diabetes mellitus), after a certain time increased induction of glutaminase occurs in the kidneys, resulting in increased NH3 excretion. This in turn promotes H"" release and thus counteracts the acidosis. By contrast, when the plasma pH value shifts towards alkaline values alkalosis), renal excretion of ammonia is reduced. 

Prolonged use or overdose may result in electrolyte or metabolic disturbances (such as hypokalemia, hypocalcemia, and metabolic acidosis or alkalosis), as well as persistent diarrhea, vomiting, muscle weakness, malabsorption, and weight loss. 

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