clinical features and investigations

Last edited 02/2018

Hyperkalaemia is often asymptomatic and is uncovered during routine laboratory testing (1).

Patients with severe hyperkalaemia may complain of non specific symptoms:

  • muscular function
    • paresthesiae
    • muscle weakness
    • fatigue
  • cardiac function  
    • arrhythmias
    • chest pain mimicking myocardial infarction, along with sweating, nausea, vomiting, extreme lethargy, weakness and giddiness (1,2)

The following investigations can be used for evaluation of suspected hyperkalaemia:

  • repeat serum measurement of potassium to identify pseudohyperkalaemia
  • other laboratory studies include:
    • blood biochemistry for kidney function - serum creatinine, S. urea, BUN etc
    • urine electrolytes and creatinine
    • arterial blood gas analysis
  • further investigations may be necessary to examine co-existing illnesses:
    • measurement of serum glucose - to evaluate for hyperglycemia
    • measurement of serum renin, aldosterone, and cortisol - to further investigate kidney and adrenal function
  • consider urgent ECG in patients with
    • a serum potassium >6.0mmol/L (severe hyperkalaemia can still be present in patients without obvious ECG changes)
    • symptoms of hyperkalaemia
    • suspicion of rapid-onset hyperkalaemia
    • underlying kidney disease, heart disease, or cirrhosis who have a new case of hyperkalaemia (2,3)

Note that emergency treatment is necessary if the serum potassium rises above 7.0 mmol/l or if there are ECG changes associated with hyperkalaemia.