Lyme endocarditis diagnosed by PCR testing

In their article “Lyme disease: A rare cause of infective endocarditis,” Gomez-Tschrnko and colleagues describe a patient with culture-negative Lyme endocarditis who was diagnosed based on PCR tissue analysis. [1]

A 40-year-old man presented to the emergency department with a headache that had been ongoing for 5 days and intermittent numbness in his left arm.

CT scan and MRI of the brain revealed acute subarachnoid hemorrhage and the patient was admitted to the neurology unit for medical management of acute stroke.

Additional testing “redemonstrated the previously seen density on the mitral valve in addition to perforation of the valve leaflet with 4þ mitral regurgitation,” the authors state.

“We present a new case of culture-negative Lyme endocarditis highlighting clinical characteristics that should trigger tissue PCR to diagnose this pathogen in cases of culture-negative endocarditis,” the authors state.

The patient underwent a median sternotomy with cardioplegic arrest for aortic valve replacement and mitral valve repair.

Given the patient’s exposure to cats and farm animals and his squirrel-hunting history, he was tested for Coxiella and Bartonella.

One week after the patient’s discharge from the hospital, PCR testing from mitral valve tissue returned positive for Borrelia burgdorferi.

The patient was treated successfully with doxycycline.

There was initially a low suspicion for Lyme endocarditis because of the lack of previous erythema migrans or recollection of recent contact with ticks.

“Convalescent serology was never rechecked 3 weeks after this initial presentation, and consequently he went undiagnosed, allowing for late complications to arise that may have been avoided with follow-up titers,” the authors point out.

Authors conclude:

• “… it is imperative to be aware that Borrelia species are a documented cause of infective endocarditis.”
• “It is important to keep this rare causative organism in the differential diagnosis in cases of culture-negative endocarditis when the valve pathology suggests an unusual pattern and it is critical to send tissue for PCR to confirm the diagnosis.”