A case of Brucella endocarditis in association with superficial femoral artery thrombus

Introduction

Brucellosis is a zoonotic disease caused by Brucella spp., a Gram-negative coccobacillus. It is transmitted by direct contact with the infected animal or via its secretions or by the ingestion of non-pasteurized milk products. ¹ Endocarditis is a rare complication of brucellosis that is encountered in less than 2% of patients with brucellosis. However, it does have a high mortality rate. ² Mert et al. reported it in 0.7% of patients with brucellosis in their case series. ³ We report a case of Brucella endocarditis associated with superficial femoral artery thrombus, treated only with medical treatment.

Case history

A 34-year-old man visited the emergency department with fever and a one-week history of increasing effort dyspnea. During the initial examination his body temperature was 38.0°C, heart rate was 92 beats/min, blood pressure was 90/60 mmHg and a grade 3/6° systolic murmur and diastolic rub were detected at the mitral focus. A laboratory examination revealed a total white blood count of 14,000 K/uL, haemoglobin 10.3 g/dL, hematocrit 29.3%, platelet 195,000 K/uL, erythrocyte sedimentation rate 64 mm/h and C-reactive protein 86 mg/dL. Blood biochemistry tests were normal except for an increase in lactate dehydrogenase. The patient was hospitalized with a pre-diagnosis of infective endocarditis. Transthoracic echocardiography demonstrated a mobile mass consistent with mitral stenosis (mitral valve area 1.2 cm²) and vegetation. Transesophageal echocardiography showed a mobile mass of 7 × 10 mm, consistent with vegetation on the anteromedial leaflet of the mitral valve. Penicillin G and gentamicin therapy was started due to a pre-diagnosis of sub-acute infective endocarditis. Recurrent fever (38.5°C) continued despite medical treatment and Brucella spp was grown in the blood culture. The brucella tube agglutination test revealed a positive titre of 1/1280. The Brucella endocarditis diagnosis was established and the treatment was changed to rifampicin plus doxycycline plus trimetoprim-sulfametoxazol. On the sixth day of antibiotherapy, the fever subsided and the patient's status improved. Subsequently the patient developed a pain in the right leg and numbness in his big toe. A coloured doppler ultrasonography of the lower extremity demonstrated a hyperechoic thrombus totally occluding the lumen of the 1/3 proximal part of the right femoral artery; no thrombus was detected in the venous system of the lower extremity. He was given 300 mg/day acetylsalicylic acid. Control transesophageal echocardiography performed at the eighth week, revealed no major change in the size of vegetation on the posterior leaflet, apart from an insignificant reduction in its size. Follow-up after six months showed no vegetation. At the seventh month, a doppler ultrasonography showed a decrease in the size of the arterial thrombus and the antibiotherapy was stopped.

After twelve months of follow-up the patient was free of any complications or problems.

Discussion

Brucellosis is a common zoonotic disease. A definite diagnosis of brucellosis can be made through isolation of Brucella spp. from blood culture. ¹ A definite diagnosis of infective endocarditis was made in our patient via a positive blood culture of Brucella spp. and echocardiographic findings.

The aortic valve is the most commonly affected valve but brucellosis may affect both the natural valve and the prosthetic valve. A combination of both medical and surgical procedures is generally used for its treatment. ⁴ Although few in number, cases of Brucella endocarditis with non-surgical treatment have been previously reported. ^3,5–8

Only medical treatment was used in our case and the vegetation disappeared at the sixth month of treatment.

Vascular complications are rarely seen in brucellosis. Although venous thrombosis is commonly seen, few cases with thrombosis of the abdominal aorta and arterial aneurysm formation have been reported. ^9,10 In our case, coloured doppler ultrasonography of the lower extremity showed a thrombus in the proximal part of right superficial femoral artery.

As a result both Brucella endocarditis and arterial thrombosis are two rarely seen complications of brucellosis.

In this regard, our case is the first published in English, in which these two rare complications were seen together, and they were treated successfully with just medical treatment. Although the suggested treatment for Brucella endocarditis is the combination of medical and surgical treatment, treatment with antibiotic therapy alone can be presented as an alternative in cases where no prosthetic valve was used and where no cardiac complication had occurred.