Causes of Facial Paralysis

I. UMN Facial Paralysis

• Lesion Site: Supra-nuclear (from cerebral cortex to the facial nucleus)
• Causes:
  1. Trauma
  2. Inflammation (e.g., encephalitis, brain abscess)
  3. Brain Tumors
  4. Cerebral Vascular Accidents (thrombosis, hemorrhage, embolism)
  5. Degenerative Diseases (Multiple Sclerosis)

II. LMN Facial Paralysis

A) Intracranial Causes

1. Lesion in the pons affecting the facial nucleus (similar causes to UMNL)
2. Lesion at the cerebello-pontine angle (e.g., Acoustic Neuroma, arachnoid cyst, congenital cholesteatoma)

B) Intra Temporal (Otogenic) Causes

(During its course in the temporal bone)

1. Idiopathic: Bell’s palsy
2. Traumatic:
   • Accidental (e.g., birth trauma, transverse temporal bone fracture)
   • Operative (e.g., during mastoidectomy)
3. Inflammatory:
   • Bacterial (secondary to otitis media or malignant otitis externa)
   • Viral (e.g., Herpes Zoster Oticus/Ramsay Hunt Syndrome)

C. Extracranial (Infratemporal) Causes

1. Malignant parotid gland tumors
2. Traumatic:
   • Accidental
   • Surgical (e.g., during parotidectomy)
   • Birth trauma due to forceps pressure over the stylomastoid foramen (usually incomplete and transient)
3. Inflammatory:
   • Peripheral neuritis (viral or diabetic mellitus)

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