Rocky Mountain spotted fever

Abstract

The epidemiology, pathogenesis, clinical features, and treatment of Rocky Mountain spotted fever are reviewed. Rocky Mountain spotted fever is a severe infection caused by Rickettsia rickettsii transmitted to man by various species of ticks. High-incidence areas exist in the southeast and south central United States. Only 60-70% of patients with the disease report a history of tick bite or exposure to tick-infested areas. The disease is initially characterized by fever, headache, gastrointestinal complaints, myalgia, and a generalized rash. In several days generalized vasculitis may lead to periorbital edema and nonpitting edema of the face and extremities. Central nervous system involvement is common. Because signs and symptoms associated with the disease are nonspecific, the diagnosis is often delayed or missed. Traditionally diagnostic confirmation relied on serologic testing, but an indirect fluorescent antibody assay will soon be commercially available. Rocky Mountain spotted fever is usually treated with the rickettsiostatic agents chloramphenicol or tetracycline, but few comparative data on these agents in patients with the disease are available. For patients who cannot tolerate oral medications, intravenous chloramphenicol sodium succinate is the preferred treatment; chloramphenicol is also the drug of choice for children less than eight years of age. Otherwise, oral tetracycline hydrochloride is the drug of choice. Antibiotic therapy should be continued for 7-10 days or until the patient is afebrile for two to five days. All cases of Rocky Mountain spotted fever must be reported to the Centers for Disease Control. The best ways to decrease the morbidity and mortality of the disease are to increase awareness of its signs and symptoms and to prevent exposure to ticks.