Infantile Guillain-Barré Syndrome Presenting with Severe Opisthotonic Posturing and Irritability: a Case Report

Introduction Guillain–Barré syndrome (GBS) is an acute immune mediated polyradiculoneuropathy that typically presents with rapidly progressive weakness and areflexia, supported by characteristic cerebrospinal fluid (CSF) and electrophysiological findings. In infants, atypical features, particularly prominent pain, can obscure early motor deficits, contributing to delayed recognition as illustrated by this case. Case A previously healthy 10-month-old boy initially hospitalized for post varicella dehydration developed progressive hypotonia, irritability, and cervical hyperextension, prompting suspicion of meningoencephalitis despite an unremarkable infectious work up aside from mildly elevated CSF protein. As his neurological status deteriorated, repeat investigations revealed cranial nerve root and cauda equina enhancement on MRI, further increased albuminocytological dissociation, and a severe demyelinating polyneuropathy on electromyography, confirming GBS. Discussion Our case illustrates different challenges in diagnosis and management of GBS in an infant. Pain in the form of opisthotonic posturing due to radicular irritation dominated the clinical picture which raised first concerns about a meningo-encephalitis and it was treated accordingly. Additionally, the administration of steroids prior to GBS diagnosis could potentially have worsened the clinical course, which underlines the value of reaching a diagnosis before committing to immunomodulatory treatment. Serial diagnostic investigations can help if initial studies are unrevealing. Conclusion In an infant presenting with opisthotonic posturing and an initially negative infectious work-up, peripheral and radicular causes—including GBS—should be considered early in the diagnostic process.