Neurology
Bell's Palsy
벨마비
Idiopathic peripheral facial nerve (VII) palsy
- How common
- 20–30/100k/year
- Typical age
- Ages 15–60 (peak 30–40s)
What is it?
HSV reactivation triggers facial nerve inflammation/edema; compression within fallopian canal causes palsy.
Commonly affected: Entire ipsilateral face (including forehead)
How it develops
- Viral reactivationHSV-1 reactivation from latency
- Neural inflammationInflammation/edema of facial nerve
- Canal compressionCompressed within narrow fallopian canal
- Nerve injuryNeuropraxia or axonotmesis
Symptoms
- Unilateral facial palsyCannot wrinkle forehead (peripheral)
- Inability to close eyeBell's phenomenon (eye rolls up)
- Mouth droopingAsymmetric smile
- Altered tasteAnterior 2/3 tongue (chorda tympani)
- HyperacusisStapedius paralysis
How it is examined
- House-Brackmann gradeParalysis severity grades 1–6
- Peripheral vs centralForehead involved = peripheral
- OtoscopyExclude Ramsay Hunt (HZ)
Imaging
Usually clinical; imaging not needed.
- Clinical
MRI if atypical or no improvement (rule out tumor, MS).
- Facial nerve enhancement
- Normal IAC
Non-surgical care
- Oral steroidsPrednisolone 60 mg/day x 5 days, start <72h
- Antiviral (selective)Valacyclovir (combination if severe)
- Eye protectionArtificial tears, ointment, eye patch at night
- Facial exercisesMirror exercises for facial movements
- ObservationUsually improves <3 weeks, full recovery 3–6 months
Conservative options are generally tried first. Medications listed here can have side effects — discuss them with your prescriber.
When surgery is considered
Refractory or traumatic facial nerve injury
Procedures that may be discussed
- Facial nerve decompression
- Facial nerve graft
- Upper eyelid gold weight
Outlook
70–85% full recovery; severe cases/elderly may have sequelae.