Intravenous Immunoglobulin Therapy for Cerebral Vasculitis Associated with Rocky Mountain Spotted Fever

Rocky Mountain spotted fever is a tick-borne illness that is prevalent in the south and the central United States, primarily during the summer months. Patients with delayed diagnosis can experience increased mortality and morbidity, particularly poor neurological outcome. We present a case of a 7-year-old girl with Rocky Mountain spotted fever who was admitted with severe neurological changes and septic shock on day 8 of illness. She was initially diagnosed with Kawasaki disease and treated with intravenous immunoglobulin. Her treatment also included doxycycline, vancomycin, and ceftriaxone due to concerns regarding Rocky Mountain spotted fever and bacterial sepsis. During hospitalization, the patient required mechanical ventilation for respiratory distress, inotropic support, and fluid resuscitation for hypotension. Titers for Rocky Mountain spotted fever were ultimately positive, with magnetic resonance imaging of the brain demonstrating numerous punctate foci of restricted diffusion within the supratentorium, including the corpus callosum and basal ganglia. Although the patient presented late in the disease course, she ultimately had a good neurological outcome. We theorized that administration of intravenous immunoglobulin prevented ongoing neurological injuries from the cerebral vasculitis, which are associated with Rocky Mountain spotted fever.