Introduction
Infective endocarditis (IE) is a serious diagnosis that occurs around 30
new cases per million worldwide, it is a challenging condition that
requires the most attention for early diagnosis and proper treatment
[1-3]. IE can occur following valvular problems and other heart
surgeries and devices and leads to fatal cardiac and non-cardiac
manifestations. Due to the multi-organ damages caused by IE, early
detection with laboratory examinations, transesophageal echocardiography
(TEE), imaging, and cultures are required and definite treatment with
antibiotics or even surgery is critical [4-6]. One of the
difficulties in IE diagnosis is blood culture-negative endocarditis
(BCNE). Although BCNE is decreased due to advanced diagnostic methods,
it is responsible for approximately 20% of infective endocarditis [7,
8]. Based on documented evidence, the organisms responsible for BCNE
are mostly Bartonella, Coxiella, and Chlamydia species [7, 9]. among
these organisms Bartonella species are responsible for the most number
of BCNE in recent years [10].
Q fever is a zoonotic endemic disease caused by Coxiella burnetiiwhich can cause BCNE in patients who underwent valvular surgeries and
other chronic heart problems. Patients having Q fever are commonly
asymptomatic, while others have different non-specific symptoms;
therefore, its diagnosis depends on the patient’s history of animal
contact especially in endemic regions [11, 12].
Based on different surveys, Iran is one of the regions with C.
burnetii endemicity, and due to the broad contact with domestic
animals, Q fever has a high prevalence in our region; therefore, we
should consider this domestic disease as a probable cause of BCNE [13,
14]. In this case report, we are presenting a patient with Q fever
endocarditis with a history of chronic endocarditis and multiple valve
replacement.