Rocky Mountain spotted fever. A clinical review based on 48 confirmed cases, 1943-1986

We reviewed 48 cases of Rocky Mountain spotted fever seen between 1943 and 1986. The data provided a view of the diverse presentations and manifestations of this disease. Exposure to a rural environment or to dogs was the rule, and over two-thirds of patients specifically remembered tick exposure. Clinical presentation was highly variable. Although fever, headache, and rash were each common, only 62% had the complete triad. Neurological symptoms and signs were common in this series. Cerebrospinal fluid abnormalities, particularly leukocytosis, were the rule in those patients who underwent lumbar puncture. Neurologic sequelae occurred in several patients. Multiple other organ systems were involved at presentation or during the course of illness--gastrointestinal, cardiovascular, pulmonary, renal, muscular, hematologic. These manifestations could, and often did, confuse physicians seeing these patients initially. They further accounted for the diverse complications seen. Outcome was good in this series. Mortality rate was 2%, and most patients recovered without sequelae. However, morbidity during hospitalization was often severe. Even in an endemic area with high index of suspicion, the diagnosis of RMSF was often delayed, usually because of failure of the physician to consider this possibility at initial presentation. This series emphasizes the importance of considering RMSF in any febrile patient in an endemic area, regardless of "atypical" presentation or apparent lack of tick exposure.