Rare Case of Chronic Coxiella Endocarditis Without Fever or Classic Risk Factors

Abstract

Background: “Q-fever” is a zoonotic infectious disease caused by Coxiella burnetii which is most commonly transmitted globally through unpasteurized animal products or aerosolized fluid. This zoonosis is not thought to be common in developed countries due to modern utilization of pasteurization but risk for transmission remains high in those with extended contact with livestock and cattle. Acute Q-fever presents with an illness characterized by high fevers, myalgias, and segmental pneumonia, but rarely it may progress to chronic Q-fever. Chronic Q-fever most often presents with a culture-negative endocarditis with or without renal impairment and can be fatal if left untreated. Case Report: In this case report, we present a 72-year-old male with a 3-month history of body pain, cough, and weight loss who was eventually discovered to have an afebrile presentation of Coxiella endocarditis. This patient was found to have a mitral valve vegetation diagnosed through transesophageal echocardiography and had positive serology for chronic Q-fever. Surprisingly, this patient had no classical exposures, no history of valvular dysfunction or prosthesis, and no clinical signs suggesting endocarditis, making his case markedly atypical. He was placed on a 12 -18-month course of antibiotics and was monitored on an outpatient basis. Conclusion: Although chronic Q-fever is rare its variable presentation may cause diagnostic error if it is not kept on the differential. A transesophageal echocardiogram should be strongly preferred due to its superior visualization of heart valves. Serology remains the gold standard for diagnosis of Coxiella. When dealing with culture-negative endocarditis, clinicians should retain a high index of suspicion of Coxiella and obtain serologies for diagnosis