Lower respiratory tract involvement in Rocky Mountain spotted fever.

A retrospective study of 35 patients with Rocky Mountain spotted fever was undertaken to determine the frequency of respiratory symptoms, as well as to analyze the types of pulmonary problems encountered to hospital patients. Cough, present in only 33% of patients, led to an incorrect initial diagnosis and delay in therapy in eight individuals. Lower respiratory tract involvement (rales, abnormal chest roentgenograms, and abnormal gas exchange) was present in 42% of patients at some point during the illness. The conditions of nine patients deteriorated during the first week of hospitalization. Pulmonary edema (probably noncardiogenic) was the usual explanation for worsening gas exchange. Bacterial pneumonia and hemorrhage were detected in only two patients.