Myocarditis: A rare manifestation of acute Q fever infection

Abstract

Myocarditis is a rare disease manifestation of acute Q fever caused by infection with Coxiella burnetii, an infectious Gram-negative proteobacteria. C. burnetii has a large animal reservoir and is often transmitted to humans during animal birth. Acute Q fever has a nonspecific disease presentation leading to delayed treatment and potentially worsened clinical outcomes. We describe a case of an otherwise healthy adult man with angina, ST elevations, and positive cardiac troponins-all findings suggestive of acute coronary syndrome. Cardiac catheterization revealed no significant coronary blockages or abnormalities. On echocardiography he was found to have heart failure with reduced ejection fraction. The patient's social history included several risk factors for Q fever. Serologic testing returned positive for anti-C. burnetii antibodies, and a diagnosis of acute Q fever myocarditis was made. The patient was appropriately treated with a course of doxycycline and clinically improved. <Learning objective: Q fever has a nonspecific presentation often leading to a delayed or missed diagnosis, resulting in worsened morbidity and mortality. Patients with angina-like chest pain and risk factors for Q fever should promptly be tested for infection with C. burnetii. Cardiac magnetic resonance imaging is a useful tool to improve diagnostic accuracy, with positive serology confirming the diagnosis. Treatment includes a course of antibiotics-often doxycycline.>.

Keywords: Coxiella burnetii; Myocarditis; Q fever.

Fig. 1

Chronic lower extremity lesions.

Fig. 2

Electrocardiogram tracing revealing sinus rhythm with premature atrial complexes, ST elevation to anterior leads with a prolonged QTc (464 ms).

Fig. 3

Cardiac magnetic resonance image revealing normal left and right ventricular size and function, left ventricular ejection fraction of 55%, and no evidence of intramyocardial fibrosis/scar, infiltration, inflammation, or hemodynamically significant valvular pathology.