Here is the aetiology of facial nerve palsy.
I- Supra nuclear causes (Upper Motor Neuron Lesion [UMNL]):
- Trauma to head.
- Meningitis, encephalitis, and abscess.
- Brain tumors.
- Stroke: Hge, thrombosis, embolism.
II- Peripheral causes (Lower Motor Neuron Lesion [LMNL]):
(A) Intracranial:
1) In pons: Congenital nuclear aplasia, Basal meningitis, Pontine Haemorrage, Pontine tumors, Multiple sclerosis.
2) In CPA: Congenital cholesteatoma, Meningioma, Vestibular schwannoma.
(B) Cranial (intratemporal)
1) Traumatic:
- Birth trauma: forceps delivery.
- Fracture especially transverse type.
- Surgical: mastoidectomy, stapedectomy.
2) Inflammatory:
- Acute otitis media with dehiscence in facial canal.
- Chronic suppurative otitis media, especially cholesteatoma.
- Herpes zoster oticus (Ramsy – Hunt syndrome).
- Malignant otitis externa.
3) Neoplastic:
- Glomus tumor.
- Squamous cell carcinoma of middle ear.
- Aconstic neuroma.
4) Idiopathic: Bell’s palsy
The commonest cause.
(C) Extra cranial
- Trauma: cut wound in parotid or face surgery.
- Sarcoidosis of the parotid.
- Tumor: malignant parotid tumors
(D) Miscellaneous
- Polyneuritis (Guillane – Barre Syndrome).
- Diabetes mellitus.
- Lyme disease.
- T.B.
- Milkersson Rosenthal Syndrome.