Meningovascular syphilis after 'appropriate' treatment of primary syphilis.

Meningovascular syphilis developed in a patient two years after the treatment of primary syphilis with a single intramuscular injection of 2.4 million units of penicillin G benzathine as recommended by the Centers for Disease Control. Although it could not be established with certainty whether this infection represented a reinfection or a treatment failure, the case emphasizes the necessity for serologic follow-up examination in all patients treated for primary syphilis.