Double Trouble: Guillain-Barré Syndrome (GBS) Presenting as Overlapping Miller Fisher Syndrome (MFS) and Pharyngeal-Cervical-Brachial (PCB) Variant.

Guillain-Barré Syndrome (GBS) is the leading cause of acute flaccid paralysis in India following the decline of poliomyelitis. Classical GBS typically presents with ascending symmetrical weakness and areflexia, while atypical variants, such as Miller Fisher Syndrome (MFS) and the Pharyngeal-Cervical-Brachial (PCB) variant, show distinct clinical patterns that are often under-recognized, particularly in resource-limited settings. This report describes a rare case of a 45-year-old previously healthy woman who developed progressive ophthalmoplegia, bulbar weakness, neck flexor weakness, and proximal upper limb weakness, along with areflexia, following a mild upper respiratory tract infection. Sensory function and lower limb motor strength remained intact. The differential diagnoses included brainstem stroke, myasthenia gravis, and diphtheritic polyneuropathy. Cerebrospinal fluid analysis revealed albuminocytologic dissociation, and nerve conduction studies showed a demyelinating sensorimotor polyneuropathy predominantly affecting the upper limbs. The presence of anti-GQ1b and anti-GT1a IgG antibodies supported an immune-mediated process. A diagnosis of GBS with overlapping MFS and PCB variants was established. The patient received a five-day course of intravenous immunoglobulin along with supportive management. Her neurological function gradually improved, with complete recovery noted at the three-month follow-up. This case highlights the importance of early recognition of overlapping GBS variants, especially in patients with cranial nerve and upper limb involvement. Greater clinical awareness and improved access to ganglioside antibody testing may facilitate earlier diagnosis and better outcomes. The coexistence of MFS and PCB variants also reinforces the concept of GBS as a spectrum disorder with shared underlying mechanisms.