A review for the emergency physician of this common tick-borne illness.

Hosts:
Audrey Bree Tse, MD
Brian Gilberti, MD


https://media.blubrry.com/coreem/content.blubrry.com/coreem/Lyme_Disease.mp3



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Tags: Infectious Diseases





Show Notes
Episode Produced by Audrey Bree Tse, MD



Background

Most common tick-born illness in North America
Endemic in Northeast, Upper Midwest, northwest California
80% to 90% in summer months

Pathophysiology

Ixodes tick (deer tick) has a 3-stage life cycle (larvae, nymph, adult) & takes 1 blood meal per stage
Deer tick feeds on an infected wild animal (infected with spirochete Borrelia burgodrferi) then bites humans
On humans, they typically move until they encounter resistance (e.g. hairline, waistband, elastic, skin fold).  It takes 24-48 hrs for B. Burgdorferi to move from the tick to the host
Pathogenesis: organism induced local inflammation, cytokine release, autoimmunity
No person to person transmission

Clinical Presentation

Stage 1: Early

Symptom onset few days to a month after tick bite
Erythema migrans rash: bulls eye rash seen in more than 90% of patients with Lyme disease (Irregular expanding annular lesion(s))
Regional adenopathy, intermittent fevers, headache, myalgias, arthralgia, fatigue, malaise

Stage 2: disseminated/ secondary

Days to weeks after tick bite
Intermittent fluctuating sx that eventually resolve
Triad of aseptic meningitis, cranial neuritis, and radiculoneuritis: bell palsy most common
Cardiac symptoms: tachycardia, bradycardia, AV block, myopericarditis

Stage 3: tertiary/ late