Key points:
All patients with irreversible facial nerve palsy require further diagnostics to exclude organic, infectious, metabolic and autoimmunological cause of such a process.
Clinicians should pay special attention to patients with new or worsening neurologic findings at any point, ocular symptoms developing at any point, or incomplete facial recovery 3 months after initial symptom onset.
The differential diagnosis should put emphasis on expansive processes, including cancers.
Depending on the suspected localization of the lesion, high-resolution CT of the temporal bone and MRI with contrast enhancement are recommended for the evaluation of the facial nerve.
In selected undiagnosed cases, repeated imagings or even explorative surgery with biopsy of tissues adjacent to the facial nerve should be considered.