What is the most common cause of hypokalemia in metabolic acidosis?

Updated: Oct 10, 2018
  • Author: Christie P Thomas, MBBS, FRCP, FASN, FAHA; Chief Editor: Vecihi Batuman, MD, FASN  more...
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Answer

Patients with hypokalemia may have relatively alkaline urine because hypokalemia increases renal ammoniagenesis. Excess NH3 then binds more H+ in the lumen of the distal nephron and urine pH increases, which may suggest RTA as an etiology for non-AG acidosis. However, these conditions can be distinguished by measuring urine AG, which will be negative in patients who have normal NH4+ excretion and positive in patients with RTA. The most common cause for hypokalemia and metabolic acidosis is GI loss (eg, diarrhea, laxative use). Other less common etiologies include renal loss of potassium secondary to RTA or salt-wasting nephropathy. The urine pH, the urine AG, and the urinary K+ concentration can distinguish these conditions.


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