Fatal ascending tonic-clonic seizure syndrome.

A fatal case of ascending tonic-clonic seizure (ATCS) syndrome resulted from the inadvertent, unrecognized use of a hyperosmolar ionic contrast agent during myelography. The patient presented with lower-extremity myoclonic jerking, agitation, hyperthermia, rhabdomyolysis, and disseminated intravascular coagulation. Emergency physicians must be cognizant of this unique toxidrome to initiate early, aggressive care.