Background: Encephalitis is an acute inflammation of the brain parenchyma with varied etiologies
that are difficult to diagnose. In majority of the cases, acute encephalitis is infective
in origin, and less commonly, it may be autoimmune. Here we report a perplexing case
of acute encephalitis.
Case Description: A 55-year-old male entomologist presented in emergency department with chief complaints
of pain in the right knee, urinary retention, and constipation. He had no other known
comorbidities. Baseline vitals and routine laboratories were unremarkable. T2 screening
of the brain was normal, and MRI spine showed no significant compressive/noncompressive
myelopathy. On the day 4 of hospital admission, the patient became drowsy for which
he was intubated and kept on mechanical ventilation. Serum electrolytes and liver
functions were normal, but serum ammonia was marginally raised (49.1 µmol/L). Metabolic
encephalopathy was suspected, and the patient was started on lactulose and rifaximin.
CSF analysis showed raised proteins, pleocytosis, and predominant lymphocytes, indicating
viral/tubercular meningoencephalitis. On this ground, intravenous methyl prednisolone
and antitubercular (ATT) drugs were started. Patient remained deeply comatose with
GCS of E1VTM1. Electroencephalogram (EEG) ruled out nonconvulsive status epilepticus.
Various reports including CSF TB-PCR, vasculitis profile, HSV IgG/IgM, Japanese encephalitis,
NMDA Ag, and VGKC Ag all were inconclusive. After these investigations, ATT was stopped.
Repeat brain MRI revealed T2 hyperintense signals with mild restricted diffusion in
bilateral parahippocampal gyri, right insular cortex, left basal ganglia, and bilateral
temporoparietal lobes in cortical, subcortical locations, bilateral cerebral peduncles,
mid-brain, pons, medulla, and cervical cord. A differential diagnosis of acute disseminated
encephalomyelitis was suspected. Patient received IV methyl prednisolone 1 g/day for
5 days and then tapered off. By day 10 in ICU, patient's GCS started improving and
he was discharged from the ICU on the 30th ICU day with E4V5M6 status. His power in
both upper limbs was 4/5, proximal weakness more than distal and in both lower limbs
was 2/5.
Conclusions: There are various etiologies of encephalitis. Clinical presentation, course, and
outcome may be quite perplexing in uncommon etiologies. Autoimmune encephalitis has
been shown to have favorable outcome over viral etiology. As a diagnosis of exclusion
and owing to its clinical course, we made a provisional diagnosis of autoimmune encephalitis.
