The Diagnostic Puzzle of Guillain-Barré Syndrome Following a Viral Prodrome: A Case Report Highlighting the Role of CSF and Electrophysiology

Guillain-Barré Syndrome (GBS) is an acute immune-mediated polyneuropathy often triggered by a viral or gastrointestinal infection. Prompt recognition and treatment are vital to prevent morbidity and complications such as respiratory failure. We present a diagnostically challenging case of a 69-year-old male with hypertension, diabetes, and atrial fibrillation who developed progressive limb weakness and recurrent falls following a self-limiting flu-like illness. Initial clinical, laboratory, and imaging evaluations were non-specific. The lack of cranial nerve involvement and the absence of clear sensory deficits contributed to diagnostic uncertainty. Cerebrospinal fluid (CSF) analysis revealed albuminocytologic dissociation, and nerve conduction studies confirmed acute inflammatory demyelinating polyneuropathy (AIDP). Early initiation of intravenous immunoglobulin (IVIG), prior to electrophysiological confirmation, led to marked clinical improvement. This case highlights the importance of considering GBS despite atypical features, the diagnostic value of CSF analysis, and the benefit of early IVIG therapy.