Etiology, Clinical Profiles, and Outcomes of Acute Encephalitis Syndrome Cases Admitted to a Tertiary Care Center in Myanmar in 2023

Background/Objectives: The diagnosis of encephalitis is a challenging problem due to the heterogeneity of clinical presentations. The objective was to determine the etiology, clinical features, laboratory parameters, radiological findings, and in-hospital outcome of acute encephalitis syndrome (AES) cases in Myanmar. Methods: A prospective descriptive study was conducted at the Neuromedical Ward of Yangon General Hospital from March to August 2023. Eighty-one AES cases were enrolled, and cerebrospinal fluid (CSF) samples were collected. A Qiastat ME Panel was used to detect viral, bacterial, and fungal pathogens. Results: Seventeen out of eighty-one (21%) cases were non-encephalitis with alternative definite diagnosis. Among the remaining 64 encephalitis cases, the exact infectious and immune etiologies were identified in 31 of 64 cases (48.4%); 26 of these (83.9%) were due to infectious causes and 5 (16.1%) were immune encephalitis. Among the infectious causes, six Herpes Simplex Virus-1-, one bacteriologically confirmed and seven probable Mycobacterium tuberculosis-, three Haemophilus influenzae-, two Streptococcus pneumoniae-, one Streptococcus pyogenes-, one Varicella-Zoster Virus (Ramsay Hunt Syndrome with meningoencephalitis)-, and two Cryptococcus neoformans-infected patients and rare causes such as Listeria monocytogenes, Burkholdelria cepacia, Sphingomonas paucimobilis, and Aspergillus were identified. One case was a dual infection with Haemophilus influenzae and Cryptococcus neformans. Abnormal protein levels and CSF pleocytosis were significantly higher among bacterial causes (p < 0.05). In total, 6.45% (2/31) of encephalitis patients with identified causes and 12.12% (4/33) of those without an identified organism had poor outcome. Conclusions: Herpes encephalitis and tuberculous meningoencepalitis were the commonest. This study highlighted that molecular testing with a multidisciplinary approach is required to ensure the right treatment on time.