Electroconvulsive therapy complicated by life-threatening hyperkalemia in a catatonic patient.

Electroconvulsive therapy (ECT) requires brief general anesthesia, and succinylcholine is a depolarizing neuromuscular blocking agent that is frequently used for this procedure. Its use leads to intracellular potassium release into the extracellular space, usually increasing the serum potassium level by 0.5-1 mEq/L, with little clinical significance. However, long-term immobilization has been associated with changes at the neuromuscular junction (up-regulation of nicotinic cholinergic receptors) and subsequent serious hyperkalemia following succinylcholine administration. We report the case of a severely obese patient, immobilized due to her catatonic state, who developed life-threatening ventricular tachycardia after succinylcholine administration for ECT. Resumption of normal physical activity reverses these neuromuscular junctional changes, allowing subsequent safe succinylcholine administration. Current drug development may eliminate the need for succinylcholine use during ECT.