Research Day
OUT OF SYNC, TICK-START MY HEART: A CASE OF LYME CARDITIS
Document Type
Abstract
Date
2021
Abstract
Introduction: Lyme disease is an infection by the spirochete Borrelia burgdorferi transmitted by the Ixodes tick in the Northeast and upper Midwest. Of the estimated ~300,000 cases/year, ~4% develop Lyme carditis manifesting as atrioventricular block (AVB) and less frequently as myopericarditis or valvular disease. We present a case Lyme disease presenting as a new-onset AVB.
Case: A healthy 18-year-old male presented to the emergency department with acute-onset palpitations, night sweats, and shoulder pain. Physical exam demonstrated tachycardia to 116 bpm with irregular rhythm, blood pressure of 102/62, and numerous erythema migrans rashes. Laboratory workup revealed increased inflammatory markers and a normal troponin. Electrocardiogram (ECG) demonstrated a 2nd degree AVB with fixed 2:1 A-V conduction. Following admission for presumed Lyme carditis, empiric ceftriaxone resulted in symptomatic improvement and serial resolution of ECG abnormalities. Lyme serology returned positive for IgM and negative for IgG. He was discharged with oral doxycycline to complete a 3-week antibiotic course.
Discussion: Identification of Lyme carditis is challenging as only 40% of patients present with erythema migrans. Per Besant et al., the Suspicious Index in Lyme Carditis predicts the likelihood of Lyme carditis in patients presenting with high-degree AVB with a sensitivity >93%. If present, patients with AVB require hospitalization for cardiac monitoring and parenteral antibiotics until restoration of 1:1 A-V conduction before transitioning to oral antibiotics. Notably, persistent high-degree AVB may necessitate pacemaker implantation. Our patient's case highlights a rare but reversible cause of high-degree AVB in healthy individuals.