American Board of Internal Medicine (ABIM) Certification Practice Exam

What is the first-line treatment for Rocky Mountain spotted fever?

1. Chloramphenicol

2. Doxycycline

3. Azithromycin

4. Amoxicillin

The correct answer is: Doxycycline

Doxycycline is recognized as the first-line treatment for Rocky Mountain spotted fever (RMSF) due to its efficacy against Rickettsial infections, which are the cause of this disease. Doxycycline works by inhibiting bacterial protein synthesis, effectively targeting the rickettsiae responsible for the illness. This antibiotic is not only recommended for adults but is also safe for use in children and pregnant women, which is particularly crucial considering the potential severity of RMSF if left untreated. In the context of choosing an antibiotic, it’s important to consider the particular pathogens involved; RMSF is specifically linked to Rickettsia rickettsii. Doxycycline has been shown to have a favorable action against this organism, leading to a decrease in mortality when administered early in the course of the disease. Delayed treatment can result in significant morbidity or even fatality, making prompt administration vital. The other options are not considered first-line therapies for RMSF due to their limited activity against Rickettsia. Chloramphenicol, while historically used for severe cases, has a higher rate of adverse effects and is not preferred as the first choice. Azithromycin and amoxicillin lack adequate coverage for rickettsial infections, further undersc