Severe Life-threatening Hypokalemia in a Cat with Suspected Distal Renal Tubular Acidosis

Objective: Description of the clinical presentation and management of a critically ill cat with profound hypokalemia associated with a suspicion of distal renal tubular acidosis (DRTA) and secondary hyperaldosteronism.

Case Summary: A cat was presented with severe generalized weakness and acute ventilatory failure associated with severe hypokalemia. The acid-base analysis and complete analytical profile of the urine confirmed the presence of a normal anion-gap metabolic acidosis with a urine pH of 7, a disorder consistent with DRTA. The high plasma renin activity, high aldosterone concentration, and low normal plasma aldosterone concentration/plasma renin activity ratio suggested secondary hyperaldosteronism. The management of the patient in the ICU was successful. No identifiable cause could be determined as a cause for the DRTA, so the disorder was assumed to be the primary problem.

New Or Unique Information Provided: DRTA is a rare disorder occasionally reported in the veterinary literature; it is especially rare in cats. Complete diagnostic evaluation was necessary to identify the reported disorders as the cause of the clinical presentation. To the author's knowledge, this is the first case reporting DRTA, and a simultaneously documented mineralocorticoid response, as a cause of a life-threatening hypokalemia.