Coexisting Thyroiditis and Carditis in a Patient With Lyme Disease: Looking for a Unifying Diagnosis

Farzane Saeidifard,Gourg Atteya,Ira Nash,Leonid Poretsky,Nicholas T. Skipitaris,Paria Zarghamravanbakhsh,Swetha Murthi

doi:10.1016/j.aace.2022.02.003

Abstract

Lyme disease, the most common vector-borne infection in the United States, causes multisystem inflammation. We describe a patient who presented with symptoms of Lyme disease, carditis, and thyroiditis. A 53-year-old woman developed fatigue and dyspnea on exertion 1 month after returning from a trip to Delaware. Her electrocardiogram (ECG) showed first-degree atrioventricular (AV) block with a P-R interval up to 392 milliseconds, in the setting of elevated free thyroxine and undetectable thyroid-stimulating hormone levels. Lyme serology was positive. She was hospitalized and started on ceftriaxone. During the second day of hospitalization, AV block worsened to second-degree Mobitz type II but converted back to first-degree AV block after a few hours. Her 24-hour I-123 thyroid uptake and scan revealed markedly diminished I-123 uptake of 1.2%. On day 4, the P-R interval improved, and she was discharged on doxycycline for 3 weeks. P-R interval on ECG and repeated thyroid function tests were normal after finishing antibiotic treatment. In our patient, known exposure to the vector, a classic rash on the chest, improvement in the symptoms, and normalization of thyroid function tests after antibiotic therapy support Lyme infection as a cause of carditis and painless, autoimmune thyroiditis. Our case highlights the importance of considering Lyme disease as a cause of painless, autoimmune thyroiditis, especially in patients with concurrent cardiovascular involvement.

Highlights

Lyme disease, a tick-borne infection caused by a spirochete Borrelia burgdorferi, is the most common vector-borne infection in the United States, with an approximate incident rate of 300,000 cases annually
During the 3rd day of hospitalization, she remained in normal sinus rhythm with1st-degree AV block, and P-R interval decreased to 320 msec
Lyme carditis usually presents as a form of self-limited conduction derangement, it can worsen and cause complications, including higher grade AV blocks, ventricular or supraventricular tachyarrhythmias, and sudden cardiac death[7,9,10,11]

Summary

Introduction

A tick-borne infection caused by a spirochete Borrelia burgdorferi, is the most common vector-borne infection in the United States, with an approximate incident rate of 300,000 cases annually. ECG showed first-degree AV block with P-R interval of 322 msec. During the 3rd day of hospitalization, she remained in normal sinus rhythm with1st-degree AV block, and P-R interval decreased to 320 msec. After starting ceftriaxone her P-R interval on ECG decreased to 316 msec, and symptoms improved.

Results

Conclusion