Acute necrotizing encephalopathy in a young adult triggered by adenovirus: a rare etiology of a devastating neurological syndrome.

Abstract

Background: Acute necrotizing encephalopathy is a rare but severe neurological disorder characterized by rapid onset of fever, altered mental status, seizures, and multifocal brain lesions, particularly involving the thalami and brainstem. Often triggered by viral infections, its pathogenesis involves a hyperinflammatory response, resulting in blood-brain barrier disruption and necrosis of neural tissue. While influenza and herpesviruses are common etiological agents, adenovirus is a less frequently reported cause.

Case presentation: A 19-year-old previously healthy male presented with a two-day history of fever, headache, altered mental status, and seizures. On admission, he was febrile, with impaired consciousness. Initial investigations showed leukocytosis, elevated C-reactive protein, and cerebrospinal fluid analysis indicative of inflammation without bacterial or fungal pathogens. Brain MRI revealed bilateral symmetrical lesions in the thalami, putamen, and brainstem, consistent with acute necrotizing encephalopathy. Polymerase chain reaction testing of cerebrospinal fluid and nasopharyngeal swabs confirmed adenovirus as the causative agent. The patient was managed with seizure control, corticosteroids for cerebral edema, and supportive care, including mechanical ventilation and physiotherapy. Follow-up imaging demonstrated regression of thalamic and pontine lesions. The patient showed partial neurological recovery but required transfer to a long-term care facility for rehabilitation, with persistent functional disability.

Conclusion: This case highlights adenovirus as a rare etiological agent of acute necrotizing encephalopathy, emphasizing the importance of molecular diagnostics in identifying atypical pathogens in severe neurological conditions.