Transverse myelitis from intraarterial penicillin.

A child was given intramuscular benzathine penicillin and experienced manifestations of sudden, irreversible transection of the spinal cord in the lower thoracic region. The biopsy supported an intravascular injection with occlusion of the spinal vasculature as the etiological mechanism. A review of similar cases reveals a recurring pattern--intramuscular injection with standard techniques and sites into a small muscle mass without evident blood return followed by rapid progression of paralysis. The problem seems to turn upon an inability to recognize the inadvertent intraarterial injection.