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Diagnosis of chagasic meningoencephalitis

CNS compromise is the most frequent manifestation of the acute reactivation of chronic infection due to T. cruzi in AIDS patients and can include meningoencephalitis or brain mass. The CSF may be normal or can be associated with mild to moderate pleocytosis with prevalence of mononuclear cells and low to mild protein levels. For these reason, in our opinion, all CSF samples from AIDS patients should be routinely sent to the parasitology laboratory for the detection of trypomastigotes. Diagnosis of meningoencephalitis is confirmed by the direct observation of trypo- mastigotes in CSF by Giemsa smear. Centrifugation of the CSF enhances the sensibility of this test.37

Current tests for diagnosis of CNS invasion in Chagas’ disease have a low sensitivity and, in some situations, they do not allow to establish the etiology. In these cases, when there exists a strong diagnosis suspect, a rapid and specific technique, such as PCR, which can detect minimal quantities of the parasite DNA, may be useful for early diagnosis and for monitoring treatment.25,53,54 Recently, several studies have reported a higher sensitivity of PCR to the laboratory diagnosis of Chagas’


Despite its low sensibility, the first approach in the laboratory diagnosis of Chagas’ disease in HIV + patients depends on the microscopic demonstrations of T. cruzi trypomastigotes in samples of blood and CSF. Alternatively, when the physicians have access to the more modern technological resources, serological and molecular techniques for the detection of T. cruzi antigens or genes, respectively, are very useful. PCR methods using formalin-fixed- (FF-) and paraffin-embedded- (PE-) tissues can achieve specific amplification of trypanosome and T. cruzi DNA sequences and can show the presence of an amplicon band of 330 bp corresponding to the amplification of minicircle kinetoplast DNA of trypanosomes. However, an accurate molecular identification of amastigotes from CNS lesions can be also achieved with a PCR technique for the amplification of repeated sequences of satellite DNA.55 In conclusion, PCR appears as a complementary method for the rapid, differential, and sensitive diagnosis of Chagas’ disease reactivation in HIV/AIDS patients.56

Anatomopathological findings associated with Chagas’ disease meningoencephalitis in AIDS patients include the presence of lymphomonocytic meningitis with the presence of T. cruzi amastigotes in the meninges and generalized cerebral edema with hemorrhagic necrosis.26

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