|Year : 2006 | Volume
| Issue : 3 | Page : 111-114
Haleem A Shawky
Department of Cardiology and Cardiovascular Surgery, Hamad Medical Corporation, Doha, Qatar
|Date of Web Publication||17-Jun-2010|
Haleem A Shawky
Non-Invasive Cardiac Laboratory, Echocardiography Section, Department of Cardiology and Cardiovascular Surgery, Hamad Medical Corporation, P.O.Box. 3050, Doha
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Shawky HA. Brucella endocarditis. Heart Views 2006;7:111-4
| Introduction|| |
Human brucellosis is a multisystem zoonotic disease with varied manifestations. It is endemic in many parts of the world, including the Middle East, Arabian Peninsula, South Asia and Central and South America. Endocarditis is a rare and often undiagnosed complication of brucellosis (< 2%) and it is the cause of 80% of deaths in brucellosis  . A case of brucella endocarditis as well as a brief review of the literature is presented.
| Case Presentation|| |
A previously well 35-year-old Indonesian female was admitted because of one month history of recurrent fever, general fatigue, night sweats, loss of weight and appetite, recurrent diarrhea, vomiting, left upper abdominal pain, shortness of breath, and left sided chest pain on exertion. Past history was unremarkable. She was employed as a housemaid for 16 moths in Doha.
On physical examination, she was lying flat, pale, with dry skin. Her vital signs were: PR 92 / min, T 38.3, RR 18/min, BP 95/50. JVP was normal. Her neck examination revealed asymmetrical thyroid swelling. Cardiac examination revealed a loud S1, Grade III/VI mid-diastolic rumbling murmur over the apex and grade II/VI pansystolic murmur over the apex. The rest of the physical examination was unremarkable. ECG showed normal sinus rhythm. Chest X-ray was normal.
Initial laboratory work up revealed WBC 7,200/ul, platelets 149,000/ul, Hb 9.5g/dl, HCT 33.3% (N 36-46), MCV 73.2 fl (N 80-96), total serum iron 9.0umol/L (N 5.4-28.6),TIBC 39umol/L (N 45-80). C-reactive protein 74.3 mg/l (n < 6), serum creatinine 169 umol/L (N 53-97), BUN 11.9 umol/L (N 3-9). Free thyroxin 27.7 pmol/ l (N 9-20), TSH 0.01mlU/I.
Transthoracic and transesophageal echocardiogram [Figure 1] and[Figure 2] revealed a large, highly mobile vegetation measuring 1.4 x 1.6 cm attached to the anterior mitral leaflet and partially occluding the mitral valve orifice in diastole. The mitral valve area (MVA) was 0.9 cm 2 by pressure half time and rest mean diastolic pressure gradient across the mitral valve was 9 mmHg. Exercise gradient was not performed. There was mild mitral regurgitation. The aortic valve was thickened with calcification and peak systolic pressure drop across was 24 mmHg. There was grade II/IV aortic insufficiency. RVSP was 37 mmHg. Left ventricular function was normal (EF 57%) with normal intracardiac dimensions.
Blood cultures were positive for Brucella species. Brucella melitenses antibodies with (Wright) agglutination test titer was 1:2,560. Abdominal ultrasound showed splenic heterogeneous triangular lesions. Thyroid ultrasound revealed multinodular goiter.
She was treated with triple antibiotic therapy with oral Doxycyclin 100 mg b.i.d, Rifampin 450mg once daily for six weeks, and Streptomycin 750 mg intramuscular once daily for three weeks. Other medications were oral ferrous sulphate three times daily, Carbimazole 15mg/day, and propanolol 10 mg p/o. t.i.d were given for the hyperthyroid state.
The general condition of the patient improved after one week of antibiotics, however, she still had intermittent low-grade fever of 38°C. Follow-up blood culture two weeks form the first culture was still positive for brucella. The patient received 2 units of packed RBCs for correction of anemia. Since there was no hemodynamic deterioration or signs of heart failure, the patient was continued on medical therapy with close follow-up by Doppler echocardiography. Elective surgery was planned.
Follow-up transthoracic and transesophageal echocardiography [Figure 3] and [Figure 4] were performed on the fourth week of antibiotic therapy and revealed marked reduction in the size of the vegetations (0.5 x 0.3 cm). The MVA was 1.3cm 2 with a mean diastolic pressure gradient of 7 mmHg.
On the fifth week of antibiotic therapy, the patient was asymptomatic, afebrile, lying fat in bed and hemodynamically stable. CBC, renal function and liver function tests were normal. On the 6th week of therapy, blood culture became negative for brucella. The patient was discharged on doxycyclin and rifampin and instructed to complete the antibiotic regimen for three months. She was scheduled for valve replacement.
| Discussion|| |
Brucellosis is a systemic zoonotic disease transmitted to humans through infected animals. It is caused by aerobic gram-negative coccobacilli, the genus Brucella, which are facultative intracellular organisms. The organisms frequently found in human brucellosis are Brucella melitensis. B. abortus, B. canis and B. suis. Brucella infection is common in some regions of the world such as the Mediterranean basin, Middle East, Arabian Peninsula, Asian, Central and South American countries and constitutes a major health problem  .
Humans are accidental hosts, contracting the disease by direct contact with infected animals or their milk. Hence, individuals recognized to be at increased risk include ranchers, farmers, abattoir workers, veterinarians and laboratory personnel. Brucella produces generalized infections with a bacteremic phase followed by localization in the reproductive organs and reticuloendothelial system, and hence, it affects multiple organs of the body with a great variety of clinical manifestations  .
Brucella endocarditis (BE) is a rare but severe complication of brucellosis. It is observed in less than 2% of brucellosis. Five large series reviewing 1500 patients with brucellosis reported only 12 cases (0.8%) with endocarditis. Although overall mortality of brucellosis is low (<1%), endocarditis is the main cause of death from infection. The reported mortality is 80% ,,,, . In an autopsy study of 44 patients who died from brucellosis, Peery and Belter reported 80% endocarditis and 43% myocardial abscesses  .
Brucella melitensis and B. abortus are the strains most often considered implicated for endocarditis in 98% of cases. Brucella melitensis is more virulent and is associated with more severe clinical course. 75% of brucella endocarditis involves the aortic valve and may lead to abscess formation in the aortic root  . The mitral valve is less frequently affected. Prosthetic valve endocarditis due to Brucellosis has also been reported. Pre-existing valve disease predisposes to valve involvement , .
Diagnosis of BE may be relatively easy in endemic areas, however, a high index of suspicion is needed when the incidence of brucellosis is low. The diagnosis will be based on epidemiological data in combination with positive cultures, serological reactions (Wright aggl. Titer >160) and ELISAs which measure IgA, G and M. Blood culture constitutes the only specific test. When predisposing factors co-exit, a brucella-positive blood culture is usually equivalent to endocarditis. Regular echocardiographic monitoring plays a primary role in these cases by detecting valvular vegetations with possible accompanying ulcerations and abscesses , .
It is widely accepted that the most effective therapy for BE is a combination of antibiotic therapy and valve replacement. After diagnosis, antibiotic therapy must be started immediately. Surgical intervention should be preformed when indicated and when the clinical condition has improved, followed by long- term antibiotic treatment , .
The recommended antibiotic combination consists of doxycycline, rifampin and amino glycoside for 3-6 months. However, conservative antibiotic treatment alone for BE is not recommended since the organism causes tissue destruction, with a tendency for progressive ulceration and significant risk of embolization. In the majority of cases, emergency or immediate surgery is indicated due to inability to control the infection and progression to congestive heart failure  . Even if symptoms improve with antibiotics, surgery is still necessary due to the embolic potential of residual vegetations or for the relief of valvular obstruction.
Timing of surgery is critical. In hemodynamically stable patients, administration of antibiotics for 6 weeks preoperatively is indicated in order to archieve sterilization. However, the presence of vegetations and congestive heart failure are indications for early surgical intervention. Hadjinikolaou, et al  and Al-Kasab et al  have operated on patients within one week after the commencement of antibiotic therapy.
In our hospital, brucella titer is part of septic laboratory work-up in patients presenting with prolonged fever because brucellosis is endemic in the Arabian Peninsula. In addition, in our hospital, echocardiography is part of the diagnostic work-up in patients suspected of infective endocarditis and in patients presenting with prolonged fever of unknown cause. Our patient did not have a definite history indicating or suggesting brucellosis but the brucella titers were markedly elevated and blood cultures were positive for brucella. There was a paucity of symptoms for infective endocarditis but echocardiography identified vegetations. Hence, the diagnosis of brucella endocarditis was made early with prompt initiation of appropriate antibiotics leading to a favorable response to medical treatment. Therefore, surgical intervention was planned upon completion of six weeks course of antibiotics.
| Conclusion|| |
The diagnosis of brucella endocarditis requires a high index of suspicion. The symptoms of brucellosis may mimic many diseases. In areas where the disease is endemic, incorporating brucella agglutination titers in the work-up of patients presenting with prolonged fever increases diagnosis. When endocarditis complicates brucella, mortality is high, therefore, Doppler echocardiography should be preformed in patients early in the course of the disease to identify vegetations. Early treatment with the appropriate antibiotics results in a more favorable clinical response, and thus reduces the need for emergent surgical intervention. Surgery can be performed after adequate sterilization has been achieved, which would result in a better outcome and prognosis.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]