Maladie de Takayasu : une entité sous-diagnostiquée en Afrique subsaharienne. À propos de cinq observations gabonaises

Résumé

La maladie de Takayasu est une vascularite affectant de façon préférentielle l’aorte et ses principales branches. Mycobacterium tuberculosis peut notamment être un facteur déclenchant du développement de la maladie de Takayasu par une réaction d’hypersensibilité. Le Maghreb et l’Afrique du Sud cumulent le plus grand nombre d’observations africaines, alors qu’entre les deux, en Afrique subsaharienne, les données parcellaires de la maladie font penser que la prévalence de la maladie est probablement sous-estimée/sous-diagnostiquée. Nous en rapportons 5 observations gabonaises.

Takayasu’s disease: an underdiagnosed entity in sub-Saharan Africa. Report of five Gabonese cases

Background. Takayasu’s disease (TM) is a vasculitis of the aorta and its main branches, Infectious diseases, especially Mycobacterium tuberculosis, can be a trigger for the development of TM by a hypersensitivity reaction, but paradoxically very few cases of the disease are reported in the literature review.

Materials and methods. Through a retrospective study carried out in the departments of internal medicine and cardiology of the Centre hospitalier universitaire de Libreville (CHUL) in Gabon, we identified all the observations of TM diagnosed in the said departments from 03/2014 to 05/2022, and rediscussed them on the basis of the criteria of Sharma et al. of 1996.

Results. Five patients (3 men, 2 women), with an average age of 38.4 years were found. 2/5 patients reported a history of pulmonary tuberculosis. There was a change in general condition (n=4), fever (n=2), arterial hypertension (n=4), a decrease in the radial pulse (n=2), rheumatological manifestations (n=3), involvement of the serous membranes (n=3). CRP was positive (n=4), and HIV1,2 serology negative (n=5). Echocardiography found pulmonary arterial hypertension (n=1), constrictive pericarditis (n=1) and valvular involvement (minimal aortic insufficiency) (n=1), and typing of aortic involvement by computed tomography or CT angiography staged Takayasu’s disease as type IIa (n=2), IIb (n=2) and IV (n=1). The patients were treated with oral corticosteroid therapy (n=5) combined with methotrexate (n=4) and azathioprine (n=1).

Discussion. The criteria of Sharma et al. from 1996, suggest a high probability of TM with a sensitivity of 92.5% and a specificity of 95%. In sub-Saharan Africa, TM requires the elimination of certain differential diagnoses, particularly syphillis, tuberculosis, salmonellosis, and atherosclerosis. Corticosteroid therapy (coupled with immunosuppressive treatment) remains effective, allowing significant remission of the disease, but comes up against the risk of opportunistic infections.

Conclusion. There is a contrast between the involvement of Mycobacterium tuberculosis in the etiopathogenesis of TM on the one hand and the endemic nature of tuberculosis on the African continent on the other hand; which contrasts with the few cases reported in sub-Saharan Africa.