Abstract
We describe a young male who presented to the emergency room with sudden onset dyspnea, and was found to have aortic root aneurysm with aortic regurgitation and cardiac tamponade. He underwent a Bentall procedure, and excised aortic root tissue showed epithelioid cell granulomas with panaortitis. He was started on anti-tubercular therapy, with which he improved. Although tubercular aortitis is fairly common, tuberculous mycotic aneurysm of the aorta is rare, with involvement of the aortic root being exceedingly uncommon. We report only the fifth case in English literature of tuberculous mycotic aneurysm of the aortic root.
Introduction
Tuberculous aortic aneurysm is a rare manifestation of tuberculosis, even in developing countries, where tuberculosis (TB) is widespread. Timely diagnosis and early intervention by combined medical and surgical therapy offers the best chance of cure.
Case history
A 30-year-old male presented to the emergency room with acute onset shortness of breath of one-day duration. His past history was significant for treatment for pulmonary TB one year ago. Examination showed a thin-built, dyspneic male with a heart rate of 110 bpm and blood pressure of 106/50 mmHg. The veins on his neck were markedly distended. Cardiac examination revealed muffled heart sounds. His chest examination revealed fine crepitations over both lung bases. Abdominal examination was unremarkable. His echocardiogram, performed in the emergency room, showed a dilated aortic root of 7 cm in diameter with severe aortic regurgitation and massive pericardial effusion with right ventricular diastolic collapse, suggestive of cardiac tamponade. A computed tomography (CT) angiogram confirmed the above findings, with the ascending aortic aneurysm leaking into the pericardial cavity with no evidence of dissection. The aortic arch and branch vessels were normal. A diagnosis of ascending aortic aneurysm with aortic incompetence and cardiac tamponade was made. The patient underwent a Bentall procedure, a composite aortic repair using a Dacron graft with a prosthetic aortic valve sewn into one end. Histopathological examination of the excised aortic root showed necrotizing granulomatous inflammation of the aorta with panaortitis. His purified protein derivative (PPD) test was positive, ELISA for HIV was negative and syphilis rapid plasma reagin (RPR) test was nonreactive. Considering the temporal association with pulmonary TB, the presence of necrotizing granulomas and the absence of vascular lesions at other large vessels (which might occur in aortoarteritis), the patient was treated for tubercular mycotic aneurysm of the ascending aorta. The patient was started on anti-tuberculous therapy consisting of isoniazid, rifampicin, pyrazinamide and ethambutol. The patient became afebrile after three weeks of treatment.
Discussion
The first case of tuberculous mycotic aneurysm of aorta was described in 1895. In 1913, Haythorn 1 described four types of tuberculous arterial disease: 1) miliary TB of the intima; 2) polypi of tuberculous tissue attached to the intima; 3) TB involving several layers of the wall; and 4) tuberculous aneurysm. Despite the widespread prevalence of TB in developing countries, tuberculous aneurysm of the aorta is exceedingly rare. Less than 100 cases of tuberculous aortic aneurysm have been reported in the English literature. 2 In 75% of the cases, mycobacteria seem to reach the aortic wall by direct extension from a contiguous focus, such as a lymph node, lung, vertebra or paraspinal abscess. It may also involve the aortic wall by direct intimal seeding or by spreading through the vasa vasorum. Combined medical and surgical therapy offers the best chance of cure. Once a symptomatic tuberculous aneurysm is identified, surgery must not be delayed. Asymptomatic aneurysms should be monitored and expanding aneurysms should be appropriately intervened. Early institution of antituberculous therapy before surgery is crucial and it should be continued post-operatively. But, in more than a third of cases, TB was not diagnosed at presentation. The exact duration of treatment and the regimen to be employed also needs further study.