Waterhouse-Friderichsen syndrome caused by Haemophilus influenzae type b in an immunocompetent young adult.

A previously healthy 19-year-old woman had a febrile illness with hypotension, progressive cyanosis, and an evolving petechial rash. Despite aggressive therapy in the face of shock and disseminated intravascular coagulation, the patient suffered a cardiac arrest and could not be resuscitated. Haemophilus influenzae type b was cultured from the blood and echovirus 30 from the cerebrospinal fluid post mortem. Fulminant H influenzae type b infection in an immunocompetent adult is rare but should be recognized as a possible cause of the Waterhouse-Friderichsen syndrome.