Rocky Mountain Spotted Fever: The Daily PANCE Blueprint

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Rocky Mountain spotted fever: The Daily PANCE Blueprint

Which of the following is recommended in treating Rocky Mountain spotted fever?

A. Clarithromycin
B. Itraconazole
C. Doxycycline
D. Metronidazole

Answer and topic summary

The answer is C, Doxycycline

  • Doxycycline is used in treating Rocky Mountain spotted fever.
  • All others are not used in treating Rocky Mountain spotted fever.
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Pearls

Rocky Mountain spotted fever (RMSF) is caused by Rickettsia rickettsii a species of bacterium that is spread to humans by the American dog tick (Dermacentor variabilis)

  • 2-14 days after tick bite will develop fevers and chills, myalgias, and headache.
  • Red maculopapular rash first on wrists and ankles then spreading centrally over 2-3 days. The face is usually spared.

Rocky Mountain spotted fever with a characteristic rash on the ankles and hands

Diagnosis

Diagnosis is primarily clinical based on fever, rash, and history of tick exposure

  • Indirect fluorescent antibody (IFA) test remains the standard method of diagnosis of RMSF.
  • Biopsy of rash with fluorescent antibody staining to detect organisms.
  • Other serologic tests that may be employed include enzyme immunoassay (EIA), complement fixation (CF) and latex agglutination (LA), indirect hemagglutination (IHA), or microagglutination (MA) assays.

Treatment

Treatment is doxycycline 200 mg PO once followed by 100 mg bid until the patient improves, has been afebrile for 24 to 48 h, and has received treatment for at least 7 days.

  • Chloramphenicol 500 mg PO or IV qid for 7 days is 2nd-line treatment.
  • No effective vaccine is available. Measures can be taken to prevent tick bites.

Smarty PANCE Content Blueprint Review:

Covered under ⇒ PANCE Blueprint Infectious Disease (6%) ⇒ Bacterial Disease (PEARLS) ⇒ Rocky Mountain spotted fever (Lecture)