Differential Diagnosis: Hypokalemia

Julie Allen, BVMS, MS, MRCVS, DACVIM (SAIM), DACVP (Clinical), Durham, North Carolina

ArticleLast Updated October 20192 min readPeer Reviewed
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Editor's note: A previous version of this article incorrectly listed hyperkalemic periodic paralysis in Burmese cats as a differential diagnosis. This has been corrected as of February 2020.

Following are differential diagnoses, listed in order of likelihood, for patients presented with hypokalemia.

  • Increased loss

    • Through the kidney (most common)

      • Chronic kidney disease

      • Loop and thiazide diuretics

      • Postobstructive diuresis (cats affected more than dogs)

      • Renal tubular disease

      • Osmotic diuresis

      • Acute metabolic acidosis secondary to lactic acid or ketone excretion

      • Primary metabolic alkalosis

      • Diuresis secondary to hyperadrenocorticism; some patients with adrenocortical tumors also produce excess aldosterone

      • High dietary sodium intake

      • Primary hyperaldosteronism, usually due to an adrenal tumor or hyperplasia

      • Excessive mineralocorticoid administration (eg, overdose of desoxycorticosterone pivalate or fludrocortisone)

      • Administration of certain drugs (eg, penicillins, carbonic anhydrase inhibitors, amphotericin B)

    • Through the GI tract

      • Vomiting

      • Chronic diarrhea

      • Ileus

    • Third-spacing (eg, loss in peritoneal fluid)

  • Transcellular shifts

    • Insulin release or administration

    • Increased endogenous catecholamines (eg, pheochromocytoma) or epinephrine administration

    • Primary respiratory or metabolic alkalosis

    • Hyperthyroidism, likely due to transcellular shifts

    • Endotoxemia

    • Refeeding syndrome

    • Hypomagnesemia

    • Treatment with or toxicosis from β2 agonists (eg, albuterol, terbutaline)

    • Hyperinsulinemia secondary to xylitol toxicosis, which stimulates the activity of the Na+/K+-ATPase pump, which catalyzes transfer of potassium in the cells

    • Hypothermia

    • Periodic hypokalemic polymyopathy (Burmese cats)

  • Decreased intake

    • Administration of low-/no-potassium intravenous fluids

    • Low-potassium diets, often acidifying diets

    • Severe anorexia (usually a confounding factor and not a primary cause)

    • Ingestion of clay cat litter containing bentonite, which binds potassium in the GI tract

  • Pseudohypokalemia; occurs secondary to lipemia and marked hyperglobulinemia*

*Only when measured by indirect potentiometry, the method used by most chemistry analyzers; blood gas analyzers using direct potentiometry are unaffected.