Episode 168.0 – Lyme Disease
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 Download Leave a Comment 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 * Symptoms occur >1 year after tick bite * Acrodermatitis chronic atrophicans: Atrophic lesions on extensor surfaces of extremities (resembles scleroderma) * Monoarthritis, oligoarthritis (knee > shoulder > elbow) * GI: Hepatitis, RUQ pain * Ocular: keratitis, uveitis, iritis, optic neuritis * Neurological: Chronic axonal polyneuropathy or encephalopathy Chronic Lyme disease (versus well-accepted Lyme disease sequelae): * Continuation of symptoms after antibiotics * Current recommendation for management is supportive care only Pediatric considerations: * More likely to be febrile than adults * Facial palsy accompanied by aseptic meningitis in 1/3 * Untreated kids can develop keratitis * Excellent prognosis if appropriately treated History * Travel, camping, woods, playing under leaves or in wood piles * Living in endemic area (Northeastern area: Maine to Virginia; upper Midwestern: Wisconsin, Minnesota; Northwest California) * Endemic in Northern Europe and Eastern Asia as well * History of tick bite (- 30-50% of patients recall tick bite)