Suxamethonium-induced hyperkalaemia 6 weeks after chemoradiotherapy in a patient with rectal carcinoma.

Suxamethonium causes an efflux of potassium (K+) ions by depolarizing acetylcholine receptors within the neuromuscular junction and produces a transient, small rise in serum K+ concentration in normal individuals that is usually of little clinical importance. Despite the clear efficacy and relative safety of suxamethonium in many patients, anaesthetists are also very aware that acute, severe hyperkalaemia resulting in important cardiovascular sequelae (e.g. malignant ventricular arrhythmias, cardiac arrest) may also occur with administration of suxamethonium in susceptible patients, including those with skeletal muscle injury or thermal trauma. In the current report, we describe a patient with rectal cancer initially treated with chemoradiotherapy who developed hyperkalaemia after suxamethonium and further discuss the potential factors that contributed to this response.