A rare fatal case of acute hemorrhagic necrotizing encephalitis secondary to COVID-19

A 25-year-old male patient presented with the complaints of fever, altered sensorium  and convulsions with RT PCR positive status for COVID-19 three weeks back.  MRI brain was advised.

MRI brain plain was perfomed on 1.5 T MRI machine and it revealed diffuse patchy areas of restricted diffusion involving bilateral fronto-parieto-temporal-occipital cortex, bilateral basal ganglia, external capsule and thalami with corresponding FLAIR signal abnormality and areas of blooming on SWI  suggestive of hemorrhagic areas with findings in favour of acute hemorrhagic necrotizing encephalitis.

Other investigations revealed raised CRP (41), Ferritin (471), LDH (706), SGPT (138)  and ESR (29).

CSF study reveals high protein, normal sugar, lymphocyte predominance with positive Pandy’s test suggestive of para-infectious etiology.

Patient was being managed with anti-epileptic, anti-viral, antibiotics, anti-fungal and IVIG. There was no clinical improvement, resulting in grave prognosis.

Acute hemorrhagic necrotizing encephalopathy is a rare complication of viral infections and has been related to intracranial cytokine storms, which result in blood-brain barrier breakdown but without direct viral invasion or parainfectious demyelination ⁽¹⁾. Accumulating evidence suggests that a subgroup of patients with severe COVID-19 might have cytokine storm syndrome ⁽²⁾. Although predominantly described in the pediatric population, acute necrotizing encephalopathy is known to occur in adults as well. The most characteristic imaging feature includes symmetric, multifocal lesions with invariable thalamic involvement ⁽³⁾.

An acute and rapidly progressive encephalopathy, including hemorrhagic necrosis of the parenchyma and associated high mortality, is typical of AHNE ^(4,5).

Characteristic findings on MRI of the brain in AHNE patients include symmetrical T2/FLAIR (T2-weighted/fluid-attenuated inversion recovery) hyperintense lesions involving the cortex, subcortical white matter, basal ganglia, thalami, brain stem, and cerebellar hemispheres, along with diffuse microhemorrhages on susceptibility-weighted imaging ^(6,7).

There is  progressive encephalopathy, vomiting , lethargy and often convulsions in most affected individuals. Along with supportive care, early use of high-dose corticosteroids, immunosuppresants  and high-dose oseltamivir may lead to lower mortality with fewer long-term sequelae of disease.

Teaching Points : Acute hemorrhagic necrotizing encephalitis is a very rare severe neurological sequelae of viral infection with poor prognosis possibly secondary to an immune response to an external inflammatory process disrupting the blood-brain barrier via cytokine storm. Treatment is mainly supportive. In present scenario of COVID-19, progressive encephalopathy and typical imaging features on MRI suggest the diagnosis of Acute hemorrhagic necrotizing encephalitis.

Written informed consent could not be obtained from patient before he passed away. All information related to patient identity has been removed.