Facial nerve palsy

Description

You have a facial nerve (also called the seventh cranial nerve) on each side of your face. Each facial nerve comes out from your brain and goes through a complex route to reach the muscles you use for facial expressions, such as raising your eyebrows and closing your eyelids.

Facial nerve paralysis may be congenital (present at birth) or acquired, i.e. due to injury or disease. Acquired causes include:

Bell's Palsy, probably due to viral infection
Tumours (acoustic neuroma, parotid gland or temporal bone tumour)
Trauma (birth, temporal bone fracture)

Clinical Features

The paralysis usually affects one half of the face. Patients with facial nerve paralysis develop flattening of the affected half of the face, with loss of forehead wrinkles, an inability to whistle and a ‘dragged’ appearance of the opposite comer of the mouth. Paralysis can affect the eye area in various ways, including drooping of the eyebrow, elevation or retraction of the upper eyelid, sagging and ectropion (sagging and outward turning of the lower eyelid and eyelashes), watering, lagophthalmos (inability to close the eye), and exposure keratopathy (drying of the cornea).

Abnormal nerve connections may form during recovery of a facial nerve paralysis. This may lead to the eyelids being excessively closed or closing when moving other parts of the face particularly the mid-face. Very rarely, abnormal connections form between the tear production pathway and chewing muscles resulting in copious and embarrassing tearing whilst eating (Crocodile tears syndrome). This can be successfully managed using repeated injections of botulinum toxin

Management

Many patients can be treated with lubricating eye-drops and ointment, and taping the eyelids closed at night. Bell’s palsy, the most common cause of facial nerve paralysis, usually resolves spontaneously within a few weeks and these measures are usually sufficient to protect the eye whilst this occurs. Injection of botulinum toxin to induce a temporary ptosis is also effective.

Surgery is required where these measures provide inadequate protection or there is no likelihood of recovery. The primary aim of treatment is to protect the cornea since poor eyelid closure may result in the drying and damage to the cornea. Other reasons surgery may be considered are to improve the appearance of the eye area and to reduce watering.

Surgery aims to correct drooping of the lower eyelid (ectropion), excessive opening and poor closure of the upper lid, and drooping of the eyebrow. Most surgery can be carried out under a local anaesthetic as a day-case procedure (see specialist practice section)

Useful Contacts

Bell’s Palsy Association Tel: 0870 44 45 460