Introduction

• Definition: serum potassium concentration > 5.5 mEq/L.
• Potassium balance is regulated by potassium intake, serum pH, serum insulin concentration, cell breakdown and potassium excretion. 
• Acute increase in serum potassium > 7.5 mEq/L can become life-threatening due to negative cardiac effects. 
• Serum potassium > 7.5 mEq/L is usually clinically significant.

Pathogenesis

Pathophysiology

• Variety of underlying causes.
• Decreased potassium excretion:
  • Oliguric or anuric renal failure Kidney: acute kidney injury (AKI).
  • Urinary tract trauma or obstruction Urinary obstruction.
  • Angiotensin converting enzyme inhibitors ACE inhibitor: overview.
  • Potassium-sparing diuretics Spironolactone.
  • Primary hypoaldosteronism.
  • Hypoadrenocorticism Hypoadrenocorticism.
• Increased potassium load:
  • Iatrogenic (oral or parenteral potassium load).
  • Heat-induced illness Heat stroke Hyperthermia.
  • Crush injuries.
  • Burn injuries Skin: burn / scald.
  • Reperfusion after thrombolytic therapy Fluid therapy: for heat exhaustion.
• Increased potassium release or shifts from intracellular to extracellular location:
  • Cell death or necrosis.
  • Chemotherapy-associated cell death Chemotherapy: general principles.
  • Acidosis Acid base imbalance.
• Trichuris vulpisinfection Trichuris vulpis.
• Ancylostoma caninuminfection Ancylostoma caninum.
• Third spacing such as chylothorax Chylothorax.
• Pseudohyperkalemia:
  • Red blood cell lysis in Akitas Akita.
  • Severe leukocytosis Hematology: platelet count.
  • Thrombocytosis Hematology: platelet count.

• Decreased renal potassium excretion by renal tubules:
  • Oliguric or anuric renal failure Kidney: acute kidney injury (AKI).
  • Urethral obstruction Urinary obstruction.
  • Aldosterone deficiency.
• Massive cell lysis, overwhelming renal tubular excretion capacity:
  • Excessive exercise.
  • Rhabdomyolysis.
  • Heat-induced illness Heat stroke Hyperthermia.
  • Burn injuries Skin: burn / scald.
  • Snake envenomation Adder bite poisoning.

• Metabolic disturbances:
  • Metabolic acidosis Acid base imbalance.
    • Diabetic ketoacidosis Diabetic ketoacidosis.
    • Ethylene glycol Ethylene glycol poisoning.
    • Lactic acidosis.
• Decreased sodium intake Blood biochemistry: sodium :
  • Increased sodium and water resorption causes dilutional effect, thus decreasing renal tubular potassium excretion.

Diagnosis

Treatment