Non-idiopathic peripheral facial palsy: prognostic factors for outcome.

OBJECTIVES: There is a lack of data on patients' and diagnostic factors for prognostication of complete recovery in patients with non-idiopathic peripheral facial palsy (FP).
METHODS: Cohort register-based study of 264 patients with non-idiopathic peripheral FP and uniform diagnostics and standardized treatment in a university hospital from 2007 to 2017 (47% female, median age: 57 years). Clinical data, facial grading, electrodiagnostics, motor function tests, non-motor function tests, and onset of prednisolone therapy were assessed for their impact on the probability of complete recovery using univariable and multivariable statistics.
RESULTS: The most frequent reason for a non-idiopathic peripheral FP was a reactivation of Varicella Zoster Virus (VZV; 36.4%). Traumatic origin had a higher proportion of complete FP (52.9%). Furthermore, in traumatic FP, the mean interval between onset and start of prednisolone therapy was longer than in other cases (5.6 ± 6.2 days). Patients with reactivation of VZV, Lyme disease or otogenic FP had a significant higher recovery rate (p = 0.002, p < 0.0001, p = 0.018, respectively), whereas patients with post-surgery FP and other reasons had a significant lower recovery rate (p < 0.0001). After multivariate analyses voluntary activity in first EMG, Lyme disease and post-surgery cause were identified as independent diagnostic and prognostic factors on the probability of complete recovery (all p < 0.05).
CONCLUSION: Infectious causes for non-idiopathic FP like VZV reactivation and Lyme disease had best probability for complete recovery. Post-surgery FP had a worse prognosis. LEVEL OF EVIDENCE: 2.