American Board of Internal Medicine (ABIM) Certification Practice Exam

Which treatment would be appropriate for a patient with Lyme disease presenting with severe systemic symptoms and erythema migrans?

1. Oral doxycycline

2. Intravenous ceftriaxone

3. Oral azithromycin

4. Oral amoxicillin

The correct answer is: Intravenous ceftriaxone

Intravenous ceftriaxone is appropriate for a patient with Lyme disease who presents with severe systemic symptoms and erythema migrans because it is the recommended treatment for more severe manifestations of the disease, particularly if neurological or cardiac involvement is suspected or confirmed. In cases where patients demonstrate severe systemic symptoms (such as significant fatigue, fever, or neurological deficits), the intravenous formulation of ceftriaxone provides more effective and robust coverage, ensuring that the antibiotic's concentrations in the plasma reach levels sufficient to tackle the more aggressive manifestations of the disease. For less severe cases, such as those that are isolated erythema migrans without systemic manifestations, oral therapies like doxycycline or amoxicillin could be effective. However, in a clinical scenario where extensive systemic symptoms are present, the escalation to intravenous therapy is warranted to rapidly address potential complications arising from the infection. This approach ensures the patient receives the best possible outcome in managing more serious Lyme disease presentations.