ID Flashcards
Lyme disease Path: Pt: Dx: Tx:
Path: Borrelia burgdorferi (gram - spirochete) spread by vector Ixodes (deer) ticks
MC white tailed deer and white-footed mice
Spring and summer
Northwest, midwest, mid-Atlantic regions of US
Pt:
Early localized
Erythema migrans (90%): expand, warm, annular, erythematous rash (classically seen w/ central clearing or “bull’s-eye” appearance) usually within a month and around area of tick bite. Lesions expands slowly over days-weeks
+/- viral-like syndrome: HAs, fever malaise, lymphadenopathy
arthritis, neuro sx, AV block, pericarditis
Dx: Clx
ELISA followed by Western blot if ELISA is positive or equivocal. During times of EM, serologic testing often negative
False positive ELISA: other spirochetal disease: syphilis, yaws; viral or bacterial illnesses other than Borrelial species
Tx:
Early dx:
Doxycycline bid x10-21 days usually preferred(doxy CI/ PCN allergy: azithromycin, erythromycin)
Amoxicillin (tx of choice in children <8, pregnancy) x14-21 days
Late/severe dx: IV ceftriaxone if 2nd or 3rd degree AV block, syncope, dyspnea, chest pain, CNS disease (other than CN VII palsy) , meningitis
PPX: Doxycycline 200mg x1 dose within 72hrs of Ixodes tick removal if the tick is present >/= 36 hours and >20% of ticks infected in the area
