Interact CardioVasc Thorac Surg 2007;6:815-817. doi:10.1510/icvts.2007.160077
© 2007 European Association of Cardio-Thoracic Surgery
Recurrent endocarditis of a bicuspid aortic valve due to Q fever
William Ngatchou,
Constantin Stefanidis,
Ahmed S.E. Ramadan* and
Didier De Cannière
Cardiac Surgery Department, Free University of Brussels-ULB, Route de Lennik 808, B-1070 Brussels, Belgium
Received 29 May 2007;
received in revised form 19 July 2007;
accepted 20 July 2007
*Corresponding author. Tel.: +32 2 555 38 17; fax: +32 2 555 66 52.
E-mail address: ahmad_sabry_cts{at}yahoo.com (A.S.E. Ramadan).
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Abstract
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A 46-year-old man was referred to our institution for a recurrent endocarditis with negative blood culture. Clinical examination and complementary investigations confirmed the diagnosis of aortic valve endocarditis with left ventricular fistula. Blood culture was negative but serological tests were positive for Coxiella burnetti. Aortic valve replacement and fistula repair were done. A combination of Doxycycline and Chloroquine antibiotics was given postoperatively with a clinical improvement. Coxiella burnetti should be systemically searched for in all cases of endocarditis even with negative blood cultures. This case is interesting because of its rarity, diagnosis, therapeutic problems and its severe complication.
Key Words: Q fever; Endocarditis; Fistula; Aortic root
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1. Introduction
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Q fever as a cause of rickettsia or Coxiella burnetti is a worldwide zoonosis [1, 2]. Farmers, vetinarians, and laboratory animal workers are more susceptible to infection than others. The patient who is infected with Q fever usually presents in an acute or chronic form; the acute form most often as flu-like syndrome and the chronic one may present as endocarditis with negative blood culture [2, 3].
A 46-year-old Caucasian male patient was referred by his general practitioner to a peripheral hospital due to persistent fever, fatigue and headache. Besides the fever, physical examination was unremarkable. Different tests were performed of which blood samples showed an important inflammatory syndrome with C-reactive protein (CRP) level 15 mg/dl and a white blood cell count (WBC) of 16,700/mm3. Transthoracic echocardiography demonstrated the presence of aortic valve vegetations without significant aortic regurgitation. Transoesophageal echocardiography (TEE) confirmed the diagnosis of endocarditis. Numerous frequent blood cultures were negative. The patient was treated with a combination of ampicillin and gentamycin for six weeks. The vegetations disappeared progressively without evidence of central or peripheral embolisation. The patient was discharged in a good condition, afebrile, with normal blood tests, namely a CRP level of 0.2 mg/dl. One month later, fever relapsed and the patient was readmitted in the same hospital. His temperature was 39 °C. TEE evaluation showed recurrence of aortic valve vegetations. Another intensive course of ampicillin and gentamycin was reiterated in addition to clarythromycine without improvement in five weeks. On the contrary, the patient presented recurrent episodes of Mobitz II AV block and deterioration in blood tests (CRP ). He was then referred to the cardiology care unit in our institution, and with clinical examination showed grade 3/6 systolic aortic murmur, confusion, moderate signs of cardiac insufficiency and without any other significant symptoms.
Blood examination showed a CRP level of 5.2 mg/dl, WBC 16,000/mm3, haemoglobin 12 mg/dl; thrombocytopenia 60,000 platelets/mm3, kidney and liver functions were normal. Blood and urine cultures were negative. Standard chest X-ray was normal; 12 leads electrocardiogram revealed a 1st degree atrio-ventricular block. TEE was performed showing a bicuspid aortic valve dysfunction with luxuriant vegetations, grade 3/4 aortic regurgitation and a para-aortic abscess related to non-coronary sinus of Valsalva. Computed tomography (CT) scan revealed a 3.7 cm para-aortic pseudoaneurysm arising from the left ventricle and calcified aortic valve (Figs. 1 and 2). A group of serological investigations was performed and a decision was made to change antibiotics into a wide spectrum including ampicillin, penicillin and gentamycin. The patient was operated upon by using usual cardiopulmonary bypass with direct intracoronary cold crystalloid cardioplegia. Intraoperative observation confirmed the presence of an incompetent calcified bicuspid aortic valve with many vegetations, para-aortic pseudoaneurysmal abscess and destruction of the left ventricular outflow tract with annular dehiscence in the non-coronary sinus and perforation in the anterior mitral leaflet. By an autologus pericardial patch – treated with glutaraldehyde – we repaired the anterior mitral leaflet perforation and the aortic annulus with continuous 6/0 Prolene sutures through the aortotomy. The aortic valve and aortic root were replaced by a FreestyleTM aortic root bioprosthesis (MEDTRONIC Inc., Minneapolis, USA) with coronary arteries reimplantation. On the first postoperative day (POD), the patient developed a septic shock despite antibiotic therapy. The gram culture of vegetations was negative. On the 3rd POD, the serology came back positive for Coxiella burnetti and a new antibiotic program including Doxycycline and Chloroquine was started with rapid notable amelioration of the patient's condition. The diagnosis was made by indirect immunofluorescence and was confirmed by polymerase chain reaction (PCR). The patient was extubated and transferred to the ward on the 6th postoperative day. Blood tests returned progressively back to normal values and follow-up TEE showed normofunctional valves with no gradient or residual regurgitation, and the ventricular dimensions were normal. The patient was discharged home on the 10th POD under cover of antibiotics which will be continued for up to one year.
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2. Comment
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Endocarditis is a very rare, severe complication of chronic Q fever. Raoult et al. have reported an incidence of one infection per million population representing <5% of endocarditis in France [1]. Q fever caused by Coxiella burnetti is a worldwide zoonosis and the reservoirs are mammals, birds, and arthropods [2]. Human infection results from inhalation of contaminated aerosols of amniotic fluid, placenta and/or contaminated wool [2]. Immunocompromised persons, pregnant females, patients with heart valve disease or valvular prosthesis, and individuals who work close to animals are more vulnerable to infection [1, 2]. In our patient bicuspid aortic valve was the only risk factor. Clinical manifestations of Q fever are not specific, most often present as flu-like syndrome, atypical pneumonia, and/or hepatitis. The chronic form may present as endocarditis with negative blood cultures [2–4]. Up to 60% of patients with acute Q fever are asymptomatic and only 4% of symptomatic patients require hospital admission [3]. Only about 2% of patients develop a chronic form where endocarditis represents the principal complication. Without treatment, Q fever endocarditis carries a very high mortality (25–60%) [3]. In the chronic form, symptoms are also quite nonspecific, so that the diagnosis is usually established late. Negative blood culture is present in 14% of all the cases of endocarditis [4]. Generally, this condition is observed in patients who had received antibiotics beforehand or patients infected with atypical pathogens like Chlamydia, Legionella, Mycoplasma, Bartonella, Brucella, Candidosis, Mycosis and Coxiella burnetti [4]. In our institution the laboratory method for Coxiella identification is indirect immunofluorescence assay (IFA), which may reveal a title of antibodies more than 1/2000 to phase I immunoglobulin G (IgG) which is highly predictive for chronic Q fever [3, 5]. Other tests for Coxiella burnetti diagnosis include PCR amplification, immunohistology and culture of samples [2, 3]. First-line treatment consists of doxycycline 200 mg twice daily with hydroxychloroquine 200 mg three times a day in a period of 1.5 up to 3 years. In case of allergy or contraindication; cotrimoxazole, rifampicine, fluoroquinolones or macrolid should be considered [1, 3]. Uncontrolled aortic valve endocarditis usually leads to severe aortic valve damage with difficult surgical management [6]. Aorto-cavitary fistulae is an uncommon but extremely serious complication of endocarditis. Anguera et al. reported a prevalence of 1.6% rising to 5.8% in patients with prosthetic valve endocarditis [7]. In our case, an extensive excision of infected tissues was performed and the wall reconstruction and anterior mitral leaflet perforation was done by an autologous pericardial patch to secure the prosthetic valve anchoring [6, 8]. Valve replacement in these cases should be achieved by aortic root bioprosthesis or homograft with coronaries reimplantation [6, 8]. Coxiella burnetti and other atypical germs have to be highly suggested and to be investigated in case of endocarditis with negative blood cultures. Early diagnosis and appropriate treatment decrease cardiac architecture destruction and surgical mortality.
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References
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Abstract
1. Introduction
