Central nervous system involvement in Chagas disease: a hundred-year-old history.

This review gives an account of central nervous system (CNS) involvement in Chagas disease, as confirmed by pathological studies. The fundamental histopathological finding associated with the acute nervous form of the disease is nodular encephalitis in multiple foci. CNS involvement probably does not occur in patients with the mild symptomatic acute form; or, in some cases, mild encephalitis in sparse foci may be present. Reactivation of chronic Chagas disease (reactivated acute nervous form), although uncommon, has been reported in immunosuppressed patients with malignant neoplasms of the hematopoietic-lymphoid system, after renal, heart and bone marrow transplantation and especially after the emergence of AIDS. Three aspects differentiate CNS involvement in immunosuppressed chagasic patients from the neuropathological picture described in the acute nervous form: the encephalitis in multiple foci tends to acquire a necrotizing feature; numerous amastigotes are always present; and many patients have the tumoral or pseudotumoral form (brain 'chagoma'). Ischemic cerebral changes associated with chronic chagasic cardiopathy (e.g. cerebral infarcts) are common. These changes, which are similar to those found in heart diseases with other causes, are considered secondary to hypoxemia following congestive heart failure, abrupt transitory fall of systemic arterial pressure and cerebral blood flow, cardiac arrhythmias and thromboembolism.