Differential Diagnosis: Hyperkalemia

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

• Pseudohyperkalemia

  • Potassium EDTA contamination

  • Hemolysis (in vitro or in vivo) or RBC leakage in certain Asian breeds that have high-potassium erythrocytes (eg, Shiba Inu) or any breed with marked reticulocytosis

  • Thrombocytosis and, possibly, marked leukocytosis (eg, leukemia)

  • Contamination with high-potassium fluids due to collection from improperly flushed IV line

• Urethral (or, less likely, bilateral ureteral) obstruction

• Acute kidney injury (oliguric/anuric)

• End-stage kidney disease (oliguric/anuric) 

• Uroabdomen

• Hypoadrenocorticism

• Chronic kidney disease

• Drug-induced/iatrogenic cause; usually only in combination with other issues (eg, decreased renal function). May decrease renal excretion and/or affect transcellular movement

  • ACE inhibitors (eg, enalapril)

  • Aldosterone antagonists (eg, spironolactone)

  • Angiotensin II-receptor blockers (eg, telmisartan) 

  • NSAIDs

  • Cyclosporine or tacrolimus

  • Trimethoprim/sulfonamides (trimethoprim decreases potassium excretion in the distal renal tubule) 

  • Trilostane

  • Mitotane

  • Heparin

  • Total parenteral nutrition

  • Digoxin

  • β blockers

• Metabolic (rarely respiratory) acidosis

• Insulin deficiency

• Massive tissue damage (eg, rhabdomyolysis, reperfusion injury after thromboembolic event, gastric torsion)

• Trichuris vulpis infection 

• Severe malabsorption

• Salmonellosis

• Perforated duodenal ulcer 

• Chylous effusions following drainage

• Peritoneal effusion (cats)

• Hyporeninemic hypoaldosteronism 

• Late pregnancy (greyhounds) 

• Acute tumor lysis syndrome

• Strenuous exercise 

• Hyperkalemic periodic paralysis

• Increased intake

  • Excessive potassium supplementation in IV fluids

  • High-dose potassium penicillin

*Order of likelihood is based on the author’s personal experience.