Guillain-Barré Syndrome Presenting With Unilateral Facial Nerve Palsy: A Rare Presentation.

Guillain-Barré syndrome (GBS) is an acute immune-mediated polyradiculoneuropathy typically presenting with symmetrical ascending limb weakness and areflexia. Cranial nerve involvement is recognized, most commonly affecting the facial nerves bilaterally. Unilateral facial nerve palsy, particularly in association with severe radicular lower back pain, is an atypical presentation and may lead to diagnostic uncertainty. We report the case of a 40-year-old woman with a background of papillary thyroid cancer who presented with severe lower back pain, progressive bilateral lower limb weakness, and acute left-sided lower motor neuron facial nerve palsy following a flu-like illness with diarrheal symptoms. Initial assessment focused on stroke and malignancy recurrence. Rapid neurological deterioration with bulbar symptoms and respiratory compromise prompted further investigation. Cerebrospinal fluid analysis demonstrated albuminocytological dissociation, and nerve conduction studies confirmed GBS. The patient required intensive care admission and was treated with intravenous immunoglobulin, resulting in significant clinical improvement. This case highlights a rare and atypical presentation of GBS and emphasizes the importance of recognizing asymmetrical cranial nerve involvement to facilitate early diagnosis and timely treatment.