RMSF is an acute febrile systemic tick illness with significant mortality caused by the organism Rickettsia rickettsii. The infection is most commonly seen in the southeast United States. The incubation period is between 2 and 14 days. The symptoms are nonspecific, with fever, severe headache, myalgias, prostration, and nausea/vomiting. The characteristic maculopapular rash usually appears on the fourth febrile day on the wrists, ankles, palms, soles, and forearms. A vasculitis may develop that can cause hypotension, edema, and petechiae. Specific organ involvement includes: cardiac (car-diomegaly, myocarditis, EKG changes), pulmonary involvement (interstitial pneumonitis), and neurologic (mild headache to lethargy, seizures, coma, transient deafness, tremor, rigidity, paralysis, ataxia, aphasia, blindness). The initial diagnosis is often made clinically. Confirmation is obtained by: serology, skin biopsy, or direct isolation and identification of the organism. Treatment is with Doxycycline or Chloramphenicol.
Please see chapter 28 on Q fever.
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