The varying neuroradiological manifestations of pediatric dengue central nervous system infection: a pictorial review from Pakistan with literature correlation.

Abstract

Dengue infection is an increasingly recognized cause of neurological complications in children, with a wide and evolving spectrum of central and peripheral nervous system involvement. This pictorial review systematically illustrates the neuroradiological manifestations of pediatric dengue using a pathophysiology- and imaging pattern-based approach, correlating characteristic magnetic resonance imaging (MRI) findings with the current literature. Neuroimaging manifestations are broadly categorized into direct viral neuroinvasive, immune-mediated, and reversible edema patterns. Direct viral involvement includes meningoencephalitis, deep gray matter involvement, and rhombencephalitis, with severe cases demonstrating the characteristic "double doughnut" sign of necrotizing encephalopathy-like encephalitis and the "Jack-o'-lantern" sign of pontine involvement. Immune-mediated white matter injury includes acute leukoencephalopathy with restricted diffusion and acute disseminated encephalomyelitis, which differ in their diffusion characteristics and temporal relationship to infection. Reversible edema syndromes include reversible splenial lesion syndrome and the less commonly reported posterior reversible encephalopathy syndrome, both associated with favorable clinical and radiological outcomes. Spinal and peripheral nervous system manifestations include myelitis and Guillain-Barré syndrome, with MRI playing a key role in differentiating these entities from other infectious and inflammatory myeloradiculopathies. Importantly, intralesional hemorrhagic changes on susceptibility-weighted or gradient recalled echo imaging, particularly within the deep gray nuclei and brainstem, represent a valuable imaging marker favoring dengue over several viral and inflammatory mimickers. Recognition of these characteristic pattern-based neuroradiological manifestations and their underlying pathophysiological correlates improves diagnostic confidence, facilitates differentiation from competing diagnoses, and guides timely management of pediatric dengue neurological disease in endemic regions.