Immune-mediated neurological manifestations of dengue virus- a study of clinico-investigational variability, predictors of neuraxial involvement, and outcome with the role of immunomodulation.

Introduction: Our aim was to study dengue-related immune-mediated neurological complications ( IMNC) during the recent epidemic. Materials and Methods: This was a cross-sectional observational study of 79 IMNC cases from 1627 laboratory confirmed dengue cases from January 2015 to January 2016 and their follow-up for 3 months. According to the World Health Organization, cases were categorized into those having dengue fever ( DF), and those having a severe syndrome that includes dengue hemorrhagic fever ( DHF) and dengue shock syndrome ( DSS). Laboratory as well as clinicoradiological data, the predictors of outcome, and the role of immunomodulation in determining the final result were analyzed. Results: Out of the 1627 confirmed dengue cases, 14.6% developed neurological complications and only 4.86% cases had IMNC. Among the IMNC seen, the majority of the patients had the onset of their manifestations in the subacute ( 7- 30 days) latency period; however, there was no mortality seen. We found Miller Fisher syndrome ( MFS), limbic encephalitis, and immune-mediated cerebellar demyelination ( IMCD) as the new findings in the IMNC spectrum. Patients with DF were more prone to developing brachial plexus neuritis and polyneuritis cranialis, whereas those patients with a severe syndrome were more commonly associated with Guillain- Barre syndrome ( GBS). Significant ( P < 0.001) predictors of central nervous system involvement were anemia, an elevated hematocrit, and the presence of DSS, whereas patients with a higher mean body temperature, DF, and elevated hematocrit were more prone to developing peripheral nervous system manifestations. The platelets counts and the hemoglobin levels had a negative correlation whereas the hematocrit value, the mean body temperature, and the alanine aminotransferase levels had a moderately significant positive correlation for the development of IMNC. The immunomodulatory therapy ( IMT), if initiated after fever abatement led to a significant clinically favorable outcome at 3 months, especially in patients with GBS, polyneuritis cranialis, and brachial plexus neuritis. Conclusion: The spectrum of IMNC is vast and may include MFS, limbic encephalitis and IMCD. Early initiation of IMT, in the presence of significant predictors, may reduce the IMNC-related morbidity.