Be Alert to ALERD: Acute Leukoencephalopathy with Restricted Diffusion—Atypical Presentation of a Rare Case

Abstract

Acute leukoencephalopathy with restricted diffusion (ALERD) is a novel entity observed in children with acute encephalopathy. It is characterized by diffusion restriction on magnetic resonance imaging (MRI), which can be the distinctive and sometimes the only imaging finding. Other routine MRI sequences may appear normal. ALERD can have infectious or noninfectious causes. In this case, we present a patient with infectious ALERD associated with influenza B virus. A 10-year-old boy presented to the emergency room with a brief history of fever and cough, followed by altered sensorium. He was irritable and ataxic. Neck stiffness was elicited upon examination. An MRI of the brain showed extensive symmetric diffusion restriction in the periventricular and deep white matter, corpus callosum, posterior limb of the internal capsule, and cerebral peduncles of both cerebral hemispheres. Cerebrospinal fluid study, blood and urine toxicology panels were noncontributory. The respiratory panel test was positive for influenza B. A diagnosis of infectious ALERD was made. Following treatment with steroids, intravenous immunoglobulin, antiglutamate agents, and supportive measures, he showed clinical and radiological improvement. The reporting of ALERD has risen in recent years due to its increased detection using MRI. Diffusion-weighted image plays the key role in the final diagnosis. Supportive care and prompt treatment of seizures are very important for better outcome. Follow-up imaging is also required to assess reappearance of white matter edema and development of cerebral atrophy or gliosis.

Keywords

acute leukoencephalopathy with restricted diffusion - ALERD - infectious ALERD - influenza - acute encephalopathy - diffuse ALERD

Ethical Approval

Ethics approval and consent to participate: Obtained and approval number—RMIEC/RIMS/400, dated December 20, 2022.

Consent for Publication

Written informed consent was obtained from the patient for publication of this case report and accompanying images.

Authors' Contributions

N.B. contributed to study design, concept, data acquisition, literature search, manuscript drafting and editing, and will act as guarantor of the article. S.A. contributed to study design, concept, literature search, manuscript drafting, and critical review. L.M. contributed to study design, concept, literature search, editing, and critical review. R.T., S.R. and A.K.D. contributed to concept, study design, and critical review. P.P. is referring consultant, and helped in concept, study design, and critical review.

Publication History

Received: 23 April 2023

Accepted: 03 December 2023

Article published online:
18 March 2024

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