Paradoxical aciduria

In patients with adequate renal function, urinary pH values are usually increased because of the decreased excretion of acid and increased excretion of bicarbonate. Urinary ammonia values are decreased because of decreased formation of ammonia in the tubules. In K depletion, is preferentially exchanged for Na and the pH of the urine may be low. This is called paradoxical aciduria. 

Inasmuch as this paradoxical aciduria results from sodium and potassium depletion, it is not surprising that the urine may again become alkaline if sodium and potassium are administered. Moreover, ammonium chloride administration to such patients may result in retention of ammonium with loss of bicarbonate in the urine, leading to acidosis. From the pathogenetic mechanism discussed, it would seem that chloride administration in the form of sodium or potassium chloride would alleviate alkalosis. In fact, the management of such patients usually involves controlled rehydration, sodium chloride administration, and compensation for the potassium depletion [49, 50]. 

With persistent prolonged vomiting of gastric contents the loss of water and electrolytes becomes severe. The response to dehydration takes precedence over acid-base adjustments. This may lead to the condition of paradoxical aciduria. The remainder of this exercise conducts you through one of the mechanisms contributing to this situation. 

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