Encephalitis due to Mycobacterium tuberculosis in France

Abstract

PurposeTwo hundred and fifty-three patients were included in a study on the etiology of encephalitis, carried out in France in 2007. Tuberculosis was the second most frequently identified cause, after HSV and with the same number of cases as VZV. The authors report the specific features of patients presenting with tuberculosis encephalitis (TE). MethodsTE patients were defined as patients presenting with encephalitis, with positive culture or PCR for Mycobacterium tuberculosis, or the association of clinical, biological, imaging, and epidemiological evidence (possible cases). Clinical, microbiological, and brain imaging data was analyzed and compared to that of other included patients. ResultsTwenty cases of TE were identified. The M/F sex-ratio was 1.5, the mean age 53years. Four (20%) patients had a history of tuberculosis before the encephalitis. The median delay between the onset of general and neurological symptoms was significantly longer for tuberculosis cases than for others (10days vs. 2; P<10−10). The median CSF protein level was significantly higher for tuberculosis cases (2.1g/L vs. 0.8g/L, P=0.002). CT scan and MRI were normal on admission for eight patients out of 17. Fourteen isolated strains of M. tuberculosis were susceptible to first-line anti-tuberculosis drugs and one was rifampicin-resistant. Six (33%) patients died during hospitalization and two were lost to follow-up. Ten out of 12 (78.6%) had persisting neurological symptoms on discharge. DiscussionDespite non-multiresistant MT strains, the case fatality rate among TE patients was high in our series. Early brain imaging is poor contributive for the diagnosis of TE.