Hyperkalemic ascending paralysis.

Hyperkalemia is a life-threatening electrolyte disturbance. The clinical presentation is most commonly related to its effects on cardiac conductivity and contractility, although weakness and respiratory compromise may occur. We describe what we believe to be the first reported case of life-threatening hyperkalemia presenting as an ascending paralysis which was associated with standard-dose trimethoprim-sulfamethoxazole therapy. The patient had mild, underlying renal disease which predisposed him to develop hyperkalemia. This case underscores the need to use caution in prescribing trimethoprim to such patients.