The lack of abundant information about brucella endocarditis lead us to collecte the materials of the 23 patients with brucella endocarditis in our hospital from July 2007 to August 2018. These data showed that 91.3% of patients was male, the age was 42.6±12.4 years old. The most common symptom in these patients was chest tightness, shortness of breath, fever and anemia. 43.5% of patients had anemia and 47.8% exhibited hyperglobulinemia. Blood culture before using antibiotics was easier to find Brucella sp. The aortic valve is most commonly involved, followed by mitral valve and tricuspid valve. The common complications were cardiac failure, pulmonary infection, hydropericardium, renal insufficiency. 2 patients died because of ventricular fibrillation and refractory heart failure. Cardiac failure (IV level) was the main reason for death.
Brucella endocarditis seemed to be more inclined to male. Previous studies and our data all showed that above 70% of patients was male [11-12]. A review reporting brucella endocarditis (1966 to 2011) also showed 75.3% of patients were male after analyzing all English and French articles in PubMed, Google and Scopus [13]. The reason for it is still unclear. Interestingly, the research about IE also showed a higher rate of male (69.4%) [14]. Research showed that male gender contributes to the progression of aortic regurgitation [15]. The high rate of endocarditis may due to high rate of damage and degeneration of valve in male.
Isolation of Brucella sp. in the blood is important for the diagnosis of brucella endocarditis. However, the positive rate was low in brucella endocarditis. The reason for the low rate may be the using of antibiotics. Our results showed that only 26.1% of patients found Brucella sp. in the blood. While blood culture performed before using antibiotics all found Brucella sp. The results indicated that it was important to perform blood culture before using antibiotics to find Brucella sp.
Koruk ST, et al showed involvement rates of the aortic, mitral and tricuspid valves were 49.1%, 43.4% and 5.7% in Brucella endocarditis, respectively [16]. Our results showed that Brucella mainly infected aortic valve (91.3%), followed by mitral (17.4%) and tricuspid valve (8.7%). The retrospective research about infection endocarditis cases also showed a higher rate of left native valve [14]. Left native valve seemed to be easier to be involved. A possible reason may be a higher pressure in left ventricle, and thus more susceptible to be damaged than other heart valves. Our results also showed that 21.7% of patients with Brucella endocarditis were congenital bicuspid aortic valve. Congenital valvular disorder made Brucella sp. easier to settle down in the damage valves.
Hyperglobulinemia was found in 47.8% of patients. Interestingly, 4 of 5 patients with renal insufficiency also exhibited hyperglobulinemia. As we known that immunoglobulin deposition is a important reason leading to chronic kidney disease [17]. Thus, the complication of renal insufficiency may due to hyperglobulinemia. The infections generally induce the formation of immune complexes, and glomerulonephritis occurs after the deposition of immune complexes in the kidney. A case report about Brucella glomerulonephritis showed that glomerulonephritis could be managed by only using antibiotic therapy, supporting our hypothesis [18]. The results also indicated that antibiotics treatment was also important to control the complication.
Antibiotics with or without surgery treatment was the main treatment for the Brucella endocarditis. Our results showed that Rifampin +tetracycline was an effective treatment for Brucella endocarditis. Keshtkar-Jahromi M, et al showed that the mortality of Brucella endocarditis was 32.7% in the only medical treatment patients, 6.7% in the combined medical and surgical treatment and total mortality was 10.7% from 1966 to 2011 [13]. While, our recent data showed the mortality in the only medical treatment patients was 18.2%, no death in combined surgical and medical therapy and the total mortality was 8.7%. Research about showed 50% of death occurred during or early after surgery mostly related to cardiac arrhythmias in Brucella endocarditis from 1991 to 2009 [11]. A more experiential heart valve replacement surgery may lead to low death in patients with combined medical and surgical treatment in our results. Two patients treated with quinolone + penicillin died because of cardiac failure in a short time after admission. Quinolone + penicillin was used because of delayed diagnosis of Brucella endocarditis. These results indicated effective antibiotics application was important to control the progression of Brucella endocarditis. Cardiac failure (IV level) was main reason for death. Koruk ST, et al showed that mortality increased 25-fold after complication with congestive heart failure, supporting our results [16].