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Tropical endomyocardial fibrosis (or Davies TEMF) is a restrictive cardiopathy characterised by endocardial fibrosis. This disorder occurs almost exclusively in tropical and subtropical regions. It was first described in Ouganda in 1948 and is the most frequent restrictive cardiopathy in Africa. The prevalence is unknown but the disorder is extremely rare in Europe. The fibrosis may affect the right ventricle (leading to adiastole with tricuspid insufficiency) or the left ventricle (causing acute mitral insufficiency, and early and severe pulmonary hypertension). The fibrosis can also be bilateral. The physiopathology of TEMF is still a matter of debate but involves the cytopathogenic effect of polynuclear eosinophils (EP). TEMF may be associated with endocardium damage caused by the granular components of EP (major basic protein, cationic protein, endoperoxydase, etc.) as a result of the following sequence of events: EP infiltration of myocardial cells, degranulation of EP, cytotoxicity of granular basic proteins and formation of a mural thrombus, potentially leading to endocardial fibrosis. The aetiology is unknown. The level of eosinophilic cells is generally normal or only slightly elevated. This finding may be explained by delayed diagnosis of children, adolescents or young adults with long-standing helminthiases (such as schistosomiases and filariases), at a stage when the eosinophilogenic response has either ended or is slowly progressive. An environmental hypothesis has been proposed, suggesting a link between cassava consumption and TEMF that could be explained by an excess of vitamin D caused by the traditional method of sun drying the cassava. The diagnosis of TEMF should be considered in any patient from an intertropical region with severe mitral insufficiency, once rheumatoid or dystrophic causes have been excluded. Echocardiography is the key examination for diagnosis. Davies TEMF shows some similarity to parietal fibroblastic Loeffler endocarditis (see this term), which has been described in temperate zones. However, in Loeffler endocarditis, the level of eosinophils is high (> 1500 cells/mm3) and this type of endocarditis occurs in the context of Chusid primitive eosinophilic syndrome or Churg-Strauss syndrome (see this term). The results of cardiological drug therapy are disappointing as patients often present at an advanced stage of the disease. Surgical treatment consists of endocardectomy and tricuspid and/or mitral valvular replacement (depending on the lesions). Postoperative mortality is high (10%), but the long-term prognosis is good and recurrence of the fibrosis has not been reported. In the absence of surgical intervention, the prognosis of TEMF is poor, with a mortality rate of over 50% in the two years following diagnosis. |