Lyme carditis, caused by infection with the spirochete Borrelia burgdorferi, is a rare but potentially fatal complication that may be prevented with rapid empiric antibiotic treatment.

In a new case report, public health officials describe two patients from areas where Lyme disease is endemic. The patients presented with vague, nonspecific signs and electrocardiogram (ECG) changes suspicious for Lyme carditis. Although borreliosis was suspected and was tested for, neither patient received antibiotic therapy while awaiting test results, and both subsequently died.

"Guidelines recommend simultaneous initiation of empirical antibiotic therapy and Lyme serologic testing when Lyme carditis is suspected. Lyme carditis can progress rapidly, and waiting for confirmatory diagnostic therapy to initiate antibiotic treatment may result in negative outcomes," write Grace E. Marx, MD, MPH, from the Centers for Disease Control and Prevention in Fort Collins, Colorado, and colleagues.

The authors note that their objective in reporting the cases was "[t]o remind clinicians of the importance of early recognition and treatment of Lyme carditis." The report was published online today in the Annals of Internal Medicine.

The first patient was a 57-year-old man from Vermont who had a 1-week history of fever, fatigue, chest pain, and shortness of breath. Erythematous macules were noted on the trunk, and ECG revealed first-degree atrioventricular block. Despite consultation with an infectious disease physician and positive results for B burgdorferi, antibiotic therapy was not initiated, and the patient died 12 days after initial presentation.

The second patient was a 49-year-old woman from Massachusetts who presented with nausea, vomiting, and severe headache. A CT scan and an ECG were normal. The patient was discharged with antiemetics and analgesics. Two weeks later, she reported syncopal episodes, fatigue, as well as bladder and bowel incontinence. An ECG demonstrated atrioventricular dissociation. Continuous cardiac event monitoring and Lyme testing were ordered. Two days later, results of Lyme testing came in positive, and antibiotics were dispensed. The patient died the following day, before the first antibiotic dose was taken.

Postmortem histopathologic evaluation of heart tissue in both patients revealed "lymphohistiocytic pancarditis with immunohistochemical and molecular evidence of B burgdorferi."

The authors acknowledge that Lyme carditis is rare and that only nine other fatal cases have been reported in the literature. However, given the risk for rapid progression in these patients, current guidelines recommend "temporary pacing by an external pacemaker for patients with symptomatic or high-risk electrocardiographic features."

Annals Intern Med. Published online October 22, 2019. Abstract

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