Pr CHBANI Kamilia Aspects radiologiques des encéphalites aiguës

The video is a medical lecture by Professor Kamilia Chbani on the radiological aspects of acute encephalitis. It begins by defining acute encephalitis as an acute inflammation of the brain parenchyma causing neurological dysfunction, with a vital and functional prognosis. The role of imaging is emphasized: confirming parenchymal involvement, establishing a positive diagnosis when clinical signs are doubtful, ruling out surgical emergencies, guiding etiological investigation through lesion topography, assessing prognosis, and detecting complications. The causes are multiple, with infectious causes being the most frequent and severe, including herpes simplex virus, enteroviruses, and influenza. Immune-mediated causes such as ADEM and autoimmune encephalitis are also discussed. The lecture details the use of CT and MRI, highlighting that CT is often normal in early stages and is mainly used to rule out contraindications to lumbar puncture. MRI is the preferred modality, with sequences including T1, T2, FLAIR, diffusion, and post-contrast T1. The importance of diffusion-weighted imaging in young children due to incomplete myelination is stressed. Several clinical cases are presented: a 10-year-old with HSV-1 encephalitis showing typical temporal lobe involvement; a neonate with HSV-2 encephalitis showing diffuse cortical and subcortical involvement; enterovirus rhombencephalitis with brainstem and cerebellar lesions; influenza-associated acute necrotizing encephalopathy with bilateral thalamic lesions; a case of tuberculous abscesses; and a case of ADEM following hepatitis A, showing characteristic demyelinating lesions with good response to corticosteroids. The lecture concludes with a summary of topographic patterns and emphasizes the importance of MRI in diagnosis and management.