Acute Leukoencephalopathy with Restricted Diffusion (ALERD) in a ۱۰-Month-Old Infant Secondary to Severe Dehydration

Background: Acute Leukoencephalopathy with Restricted Diffusion (ALERD) is a rare but clinically significant neurological syndrome in infants, often following severe systemic illness such as gastroenteritis and dehydration. Early recognition of characteristic radiologic features is critical for timely management. Case Presentation: We report a previously healthy ۱۰-month-old infant who presented with severe dehydration and metabolic acidosis after several days of vomiting and diarrhea. On admission, the patient was lethargic and hypotonic, with multiple generalized tonic-clonic seizures, dystonic limb posturing, orofacial dyskinesia (lip smacking), decreased consciousness, and visual disturbances. Physical examination, including ocular assessment, was normal. Routine laboratory investigations, including CSF analysis, CBC, HPLC, MS/MS, and urine organic acids, were all within normal limits. Brain MRI demonstrated bilateral symmetric hyperintensity of the dentate nuclei with diffusion restriction and mild occipital cortical involvement, consistent with ALERD. The patient was managed in the pediatric intensive care unit with intravenous levetiracetam, empirical antimicrobials (later discontinued), IVIG, pulse corticosteroids, and mitochondrial cocktail. Neurological deficits improved gradually: seizures resolved, dystonia and hypotonia subsided, and visual fixation returned. Follow-up MRI showed complete resolution of dentate lesions with minimal residual occipital changes. At one-month follow-up, the patient had fully recovered with no residual deficits. Conclusion: This case highlights ALERD secondary to severe dehydration in an infant. Awareness of this reversible syndrome and its characteristic MRI findings is essential for guiding treatment and avoiding unnecessary long-term interventions.

کلیدواژه ها:

ALERD ، infant encephalopathy ، bilateral dentate nuclei ، gastroenteritis ، dehydration ، reversible neurological deficit