Intermittent High-Degree AV Block, Rash, and Facial Droop with Negative Lyme PCR

Lyme disease is the most common tick-borne illness in the United States, and cases of Lyme disease have nearly doubled since the early 2000s. Symptoms and presentation vary based on severity of illness, with more serious complications of disease consisting of neurologic and cardiac dysfunction. Testing is often unreliable, which can lead to delayed diagnosis and management.

A 38-year-old woman presented to the Emergency Department with left-sided facial droop and was subsequently diagnosed with Lyme carditis. This case depicts a classic but unique triad of symptoms caused by Lyme disease: high-degree atrioventricular (AV) blockade, Bell's palsy, and erythema migrans. The patient was promptly treated with empiric i.v. antibiotics pending serology testing for Lyme disease, and her high-degree AV block improved. Initial polymerase chain reaction testing for this patient was negative, but diagnosis was later confirmed with a positive two-tiered test. Intravenous ceftriaxone therapy improved this patient's heart block, allowing for discharge on oral antibiotics. Why Should an Emergency Physician Be Aware of This? It is important to recognize potential cases of Lyme disease early so that appropriate treatment can be initiated. Lyme disease is difficult to diagnose given the wide variety of symptoms and clinical presentations coupled with routine testing that has relatively low sensitivity. Lyme cases have been increasing over the last several years, even in areas in which Lyme disease is not generally endemic. Testing limitations make obtaining a definitive diagnosis difficult, which the emergency physician should be aware of.