Fulminant Rocky Mountain spotted fever. Its pathologic characteristics associated with glucose-6-phosphate dehydrogenase deficiency.

Three patients with documented fulminant Rocky Mountain spotted fever (RMSF) (death on or before day 5 of illness) had severe multisystemic injury as shown by clinical signs and laboratory data, but on microscopic examination showed minimal evidence of the typical mononuclear leukocytic response to rickettsial vascular infection and injury. Thrombosis was more extensive than in classic RMSF, with fibrin thrombi located in foci of rickettsial infection. These patients had a rash either preterminally or not at all, particularly severe Rickettsia-associated pulmonary lesions, and other shock-related lesions, eg, centrilobular hepatic necrosis. All three patients were male blacks with glucose-6-phosphate dehydrogenase deficiency, a condition recently associated with severity of RMSF. Diagnosis of fulminant RMSF requires awareness of its pathologic and epidemiologic aspects, and use of rickettsial isolation or specific immunofluorescence.