A Rare Presentation of Guillain-Barré Syndrome With Associated Horner Syndrome: A Case Report.

Guillain-Barré syndrome (GBS) is an acute inflammatory polyradiculoneuropathy involving the peripheral nervous system. Autonomic dysfunctions are well-known complications of GBS and are major contributors to mortality. Autonomic dysfunctions are classically described during the acute phase of illness. In the literature, Horner syndrome as a manifestation of GBS has been reported in very few cases. Here, we describe a case of GBS with an acute presentation of flaccid paraparesis associated with unilateral Horner syndrome. Detecting the cause of acute flaccid paraparesis with unilateral Horner syndrome poses a diagnostic challenge, making it crucial for clinicians to maintain a heightened awareness for distinguishing between GBS and its variants, as well as other potential mimics.