More than hemifacial spasm? A case of unilateral facial spasms with systematic review of red flags.

Unilateral facial spasms (UFS) are frequently caused by hemifacial spasm (HFS), a disorder that usually results from vascular loop compression at the root exit zone of the facial nerve. However, UFS can also be a manifestation of other conditions, including brainstem tumours or demyelination, post-Bell's synkinesis, lesions of the facial nerve in the Faloppio canal and the parotid gland, dystonia, epilepsy, psychogenic conditions, tics and hemimasticatory spasm. In this report, we present a case of UFS, not due to HFS, highlighting clinical red flags for an alternative diagnosis. In addition, a systematic review was conducted to provide a comprehensive summary of UFS differential diagnoses with a list of red flags to assist neurologists in the evaluation of patients with UFS.