Valvular Involvement in Brucellosis
Introduction: Brucella endocarditis, although an uncommon complication of brucellosis, is the main cause of the mortality related to this disease. The best therapy is a combination of antibiotic administration with valve replacement. After treatment of the first episode of endocarditis, new infection may be occurred as a relapse or reinfection.
Case Presentation: In this report, we described a patient with brucella endocarditis complicated with a reinfection of the mechanical prosthetic valve after one year of follow-up.
Conclusions: Both medical and surgical management should be done for better treatment of brucella endocarditis. Repeat infection is a problem during follow-up.
Keywords: Brucella Endocarditis; Brucella Complications; Valve Replacement; Prosthetic Valves
Brucellosis is a zoonotic disease endemic to Mediterranean countries and the Middle East countries such as Iran (1, 2). About 500,000 new brucellosis cases are diagnosed each year and many others are either not diagnosed or declared (3, 4). In Iran, the spread of brucellosis is increasing, probably because of poor planning for eradication and insufficient detection programs (2). The mortality rate is less than 1%; however, 80% of the fatal cases are caused by endocarditis. The aortic valve involvement is frequently observed and both root abscesses and aneurysms occur in up to 45% of the patients (5). The most effective therapy is combination of antibiotic administration with valve replacement (4). Although some patients have been cured only by antibiotic therapy (6), the patients who continue to live after the first episode of endocarditis may experience new infection as a relapse or reinfection (7, 8).
We reported a challenging case of brucellosis, complicated by endocarditis of native aortic valve and then prosthetic aortic valve.
2. Case Presentation
A 30-year-old man with a history of drinking unpasteurized milk was admitted for weakness, arthralgia, headache, fever and night sweating. Brucellosis was diagnosed in the patient and he was discharged with medical treatment (doxycycline and rifampicin). The patient did not follow his treatment properly and after two months he presented with progressive leg edema and dyspnea. On presentation, the patient had tachycardia but was afebrile and normotensive. Cardiac auscultation revealed a decrescendo early to mid-diastolic murmur along the left sternal border. The patient had two plus lower limbs pitting edema. Laboratory tests showed negative blood cultures, an erythrocyte sedimentation rate 65 mm per hour, a C-reactive protein 111 mg per liter, a wright 1/2560 and a 2ME 1/160. Echocardiography showed severe aortic regurgitation, two large vegetations attached to the ventricular aspect of aortic cusps (Figure 1, yellow arrows) and a large echo free space anterior of aortic root indicating aortic root abscess (red arrows). The patient underwent aortic-valve replacement and aortic root abscess drainage and was given antibiotics intravenously and then orally for six months (doxycycline, cotrimoxazole and rifampicin). After a one-year follow-up, he was readmitted for severe paravalvular leakage and a large echo free space in the anterior aspect of the aortic root during routine echocardiography (Figure 2, arrow). Laboratory tests showed a 2ME 1/160 and negative blood cultures. He again underwent aortic-valve replacement and aortic root abscess drainage with good surgery results and was given antibiotics for follow-up of his treatment.
Transesophageal Echocardiogram Obtained One-Year After Presentation
Brucellosis is the most common zoonotic disease in Mediterranean countries and the Middle East countries such as Iran. It is transmitted by direct contact with infectious animals or by eating contaminated foods for example unpasteurized dairy products. Our patient had a history of drinking unpasteurized milk (1, 2). Brucella endocarditis is an infrequent complication; however, it is the main cause of the mortality related to this disease (3, 5). It is more frequent in men than in women and the aortic valve is usually affected, frequently resulting in congestive cardiac failure, which is the gross final episode (6). The combination of antibiotic administration with valve replacement is recommended as the most effective therapy (3). However Cohen et al. described cases that were cured by antibiotic therapy (6), it is not often cured by medical therapy alone and it is mostly required to proceed to surgery for replacement of the valve, continued by antibiotic treatment for long periods of time (9). The cases described herein are typical example of this entity. The patient was male, had involvement of aortic valve and had to be subjected to aortic valve replacement for control of the infectious process and cardiac failure.
Abscess formation is more common in aortic valve endocarditis than other valves endocarditis. It is more prevalent in prosthetic valve infection. Transesophageal echocardiography is very helpful in the diagnosis of vegetations and abscesses (10). The diagnosis of brucella endocarditis was not difficult in this case, in view of the context of active brucellosis and because of the echocardiographic pictures which clearly showed the valve vegetations and aortic root abscess. The strong clinical suspicion was confirmed by laboratory results. Blood cultures although very specific, introduce a quite low sensitivity (15% - 20%) (11).
There is significant variation in the time of antibiotic therapy after surgery, varying from two weeks to more than one year. However, there is some consensus about the necessity to prolong the treatment for at least three months. In our patient, antibiotic therapy was done for six months. Most authors believe that the single antibiotic therapy must be eschewed because the development of resistance has been often demonstrated in this situation. Commonly, rifampicin and/or cotrimoxazole must be added to the classic doxycycline in dosages usually higher than those recommended for other infections (3, 12).
Even after full medical treatment or both medical and surgical treatment of endocarditis, repeat infection may be occurred. We had two different terms to define this infection: relapse and reinfection. If endocarditis occurred with the same species during six months of the first event shows a relapse and if endocarditis occurred after six months of the first event shows reinfection like our patient. Molecular analyses are needed for confirmation every time it is possible. Chu et al. contended molecular analyses have more correlation with clinical description of these terms according to six months threshold (7). Relapse and reinfection are more frequent in males and in the patients who have prosthetic valves. Our patient was male and had prosthetic valve (8).
Musci et al. showed the benefit of homograft aortic root for treatment of the patients who have periannular abscess and also showed it has more benefit in native valve endocarditis toward prosthetic valve endocarditis (13). Our patient had endocarditis with periannular abscess. The St. Jude medical mechanical heart valve masters series with Silzone coating is predesignated to protect heart valve cases against microbial infection. It has also been suggested that silver treatment may progress the healing characteristics of the heart valve sewing cuff. This technology may be a valuable choice to prevent or heal prosthetic valve endocarditis (14).
Brucella endocarditis is a dangerous complication of brucellosis and is the main cause of death attributable to this disease. Antibiotic therapy usually is insufficient to eradicate the infection and surgical management is needed. Repeat infection must be considered during the follow-up of infective endocarditis.
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