clinical features and investigations
Last edited 02/2018 and last reviewed 10/2022
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.
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