Borreliosis

1. Big picture

Borreliosis = Lyme disease is a tick-borne spirochetal infection caused by Borrelia burgdorferi sensu lato. The most important exam pattern is:

Tick exposure
+ expanding erythema migrans rash
± fever, malaise, arthralgia
= Lyme borreliosis

The examiner mainly wants you to know:

1. Erythema migrans is a clinical diagnosis — do not wait for serology.
2. Lyme disease can involve skin, nervous system, heart, and joints.
3. Serology is useful in disseminated/late disease, but early tests may be negative.
4. Treatment depends on manifestation: oral doxycycline/amoxicillin/cefuroxime for most early disease; ceftriaxone for severe neurologic/cardiac disease.
5. Do not diagnose “chronic Lyme” from nonspecific fatigue alone after adequate treatment.

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