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Disseminated Lyme disease — RCPSC IM MCQ

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HardInfectious DiseasesDisseminated Lyme diseaseRCPSC IM

A patient with an expanding erythema migrans lesion and new facial palsy lives in an endemic area. Which diagnostic principle is appropriate?

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Correct answer: C — Treat erythema migrans and use stage-based serology

The best answer is “Treat erythema migrans and use stage-based serology”. Erythema migrans is a clinical diagnosis, and early serology can be negative; neurologic involvement informs testing and treatment. Waiting for seroconversion can delay care, while unrelated microbiologic tests do not address Borrelia infection. Facial palsy indicates disseminated involvement, so neurologic severity and other organ manifestations determine whether oral therapy is sufficient or parenteral treatment is required.

Reference: Canadian Public Health Laboratory Network Lyme guidance, full text: https://pmc.ncbi.nlm.nih.gov/articles/PMC2533539/