Guillain-Barré Syndrome Initially Perceived as Unilateral Facial Palsy in Epstein-Barr Virus Infection.

We encountered a case of a 21-year-old female presenting with unilateral peripheral facial nerve palsy, initially suspected to be triggered by Epstein-Barr virus (EBV) infection. The patient initially complained of numbness in both lower extremities, progressing to difficulty with mobility by day two, leading to emergency admission. Despite an initial evaluation by a neurologist in the emergency department, Guillain-Barré Syndrome (GBS) was not diagnosed, and she was admitted to internal medicine for further investigation. During hospitalization, she developed infectious mononucleosis and left-sided facial nerve palsy, prompting a referral to our otolaryngology department. Upon further evaluation, subtle weakness on the contralateral side was noted, raising suspicion of bilateral facial nerve palsy. Eventually, the case was diagnosed as bilateral facial nerve palsy associated with GBS. This case underscores the crucial role of otolaryngologists in raising suspicion for GBS when bilateral facial nerve involvement is considered. Recognizing bilateral facial nerve palsy is essential for correctly diagnosing GBS. Since bilateral facial nerve palsy can be subtle, a lack of facial expression may serve as an early diagnostic clue. Additionally, it is important to understand the association between infectious mononucleosis and GBS, as infectious mononucleosis is a common condition. This relationship will be explored in detail.