Differential Diagnosis: Hypokalemia

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

Internal Medicine

|October 2019|Peer 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.

References

DiBartola SP, de Morais HA. Disorders of potassium: hypokalemia and hyperkalemia. In: DiBartola SP, ed. Fluid, Electrolyte, and Acid-Base Disorders. 4th ed. St Louis, MO: Elsevier Saunders; 2012:92-108.
George JW, Zabolotosky SM. Water, electrolytes and acid base. In: Latimer KS, ed. Duncan and Prasse’s Veterinary Laboratory Medicine: Clinical Pathology. 5th ed. Ames, IA: Wiley-Blackwell; 2011:158-162.
Hornfeldt CS, Westfall ML. Suspected bentonite toxicosis in a cat from ingestion of clay cat litter. Vet Hum Toxicol. 1996;38(5):365-366.
Kardalas E, Paschou SA, Anagnostis P, Muscogiuri G, Siasos G, Vryonidou A. Hypokalemia: a clinical update. Endocr Connect. 2018;7(4):R135-R146.
Kogika MM, de Morais HA. A quick reference on hypokalemia. Vet Clin North Am Small Anim Pract. 2017;47(2):229-234.
Malik R, Musca FJ, Gunew MN, et al. Periodic hypokalaemic polymyopathy in Burmese and closely related cats: a review including the latest genetic data. J Feline Med Surg. 2015;17(5):417-426.
Murphy LA, Dunayer EK. Xylitol toxicosis in dogs: an update. Vet Clin North Am Small Anim Pract. 2018;48(6):985-990.
Nemzek JA, Kruger JM, Walshaw R, Hauptman JG. Acute onset of hypokalemia and muscular weakness in four hyperthyroid cats. J Am Vet Med Assoc. 1994;205(1):65-68.
Stockham SL, Scott MA. Monovalent electrolytes and osmolality. In: Stockham SL, Scott MA. Fundamentals of Veterinary Clinical Pathology. 2nd ed. Ames, IA: Blackwell Publishing; 2008:511-516.
Thiessen CE, Tofflemire KL, Makielski KM, Ben-Schlomo G, Whitley RD, Allbaugh RA. Hypokalemia and suspected renal tubular acidosis associated with topical carbonic anhydrase inhibitor therapy in a cat. J Vet Emerg Crit Care (San Antonio). 2016;26(6):870-874.
Xia Z, He Y, Yu J. Experimental acute toxicity of xylitol in dogs. J Vet Pharmacol Ther. 2009;32(5):465-469.

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Differential Diagnosis: Hypokalemia

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

Internal Medicine

References

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