Amazon, the largest tropical forest of the world, has suffered from dengue outbreaks since 1998. Cerebrospinal fluid (CSF) of patients, from Amazonas state, suspected of using a central nervous system (CNS). Viral infection was studied using molecular and immunological methods. Objective To assess the importance of CSF research in patients with acute dengue virus (DENV) infection of CNS. 

CSF samples

CSF samples of 700 patients were analyzed by reverse transcription polymerase chain reaction (RT-PCR) to detect the presence of dengue virus (DENV) RNA and by enzyme-linked immunosorbent assay (ELISA) to detect the presence of DENV specific IgM. FINDINGS DENV infection was detected in 4.3% of the CSF samples; 85.7% (24/28) by DENV IgM and 14.3% (4/28) by viral RNA .

DENV recognized by viral RNA were found to be serotypes DENV-2 (three patients) and DENV-1 (one patient). The neurological diagnosis in patients CNS infection of DENV included encephalitis (10), meningoencephalitis (10), meningitis (6), acute myelitis (1), and encephalomyelitis (1). The majority (89.3%) had intrathecal inflammation: pleocytosis, hyperproteinorrachia, and DENV IgM antibodies.

Hypoglycorrhachia and high levels of lactate in CSF were found in 36% of the patients. Co-infection (CMV, HIV, EBV, and Mycobacterium tuberculosis) was observed in eight (28.6%) cases. CONCLUSIONS We found intense inflammatory CSF that is unusual in CNS disorders caused by a dengue infection. It may be due co-infections or the immunogenetic background of the local Amerindian Brazilian population. CSF examination is an essential diagnostic support tool for neurological dengue diagnosis.

Molecular and immunological methods were used to analyze CSF from 700 patients suspected of DENV infection of CNS. Laboratory tests confirmed viral infection in 30 (4.3%) cases, presenting with acute neurological manifestations. Two patients were excluded from the study due to the lack of clinical information. Clinical and laboratory findings are shown in Table.

The median age of the 28 patients was 28.5 years old (ranging from 4 to 66 years) with 7 out of 28 (25%) patients were ≤ 18 years old, and 15/28 (53.6%) patients were male. Most patients (92.9%) lived in the city of Manaus, and only two were from other municipalities within Amazonas state (Itacoatiara and Manacapuru).

The patients with viral infection of CNS by DENV mainly presented with a headache (64.3%), disturbed consciousness (57.1%), and fever (39.3%). A cutaneous rash was observed in five (17.8%) cases. Four (14.3%) patients had a clinical history of acute dengue infection based on earlier serology diagnosis (specific IgM). The majority (71.4%) of patients developed encephalic manifestations (encephalitis, meningoencephalitis, or encephalon