Hyperkalaemia
Hyperkalaemia is an elevated blood level of potassium>5.0 mmol/L. Hyperkalaemia is a medical emergency due to the risk of potentially fatal arrhythmias.
Symptoms and Signs
Cardiac arrest. Mild breathlessness (hyperkalaemia associated with metabolic acidosis). Paraesthesiae, areflexia. Weakness. Palpitations. Abdominal pain. Hypoglycaemia. Hyperpigmentation associated with Addison’s disease.
Investigations
■ U&Es
K+>5 mmol/L (patients with chronic renal failure will tolerate higher K+ levels) – exclude haemolysis. Chronic renal failure.
■ Blood gases
Metabolic acidosis.
■ Blood glucose
Diabetic ketoacidosis.
■ ECG
Tall T waves, flat P waves, prolonged PR interval, wide QRS.
■ Creatine kinase
↑ in crush injuries.
■ Plasma cortisol
↓ adrenal insufficiency (Addison’s disease).
