Facial nerve Palsy Flashcards
summarise facial nerve palsy
Facial nerve palsy refer to isolated dysfunction of the facial nerve. This typically presents with a unilateral facial weakness. It is important to understand some basics about the pathway of the facial nerve and the function of the facial nerve to consider the causes and management.
briefly describe the path of the facial nerve
The facial nerve exits the brainstem at the cerebellopontine angle. On its journey to the face it passes through the temporal bone and parotid gland.
after the facial nerve exits the parotid gland, the facial nerve divides into which branches?
Temporal
Zygomatic
Buccal
Marginal mandibular
Cervical
what are the 3 function of the facial nerve
: motor, sensory and parasympathetic.
describe the motor function of the facial nerve
Motor: Supplies the muscles of facial expression, the stapedius in the inner ear and the posterior digastric, stylohyoid and platysma muscles in the neck.
describe the sensory function of the facial nerve
Sensory: carries taste from the anterior 2/3 of the tongue.
describe the parasympathetic function of the facial nerve
Parasympathetic: it provides the parasympathetic supply to the submandibular and sublingual salivary glands and the lacrimal gland (stimulating tear production).
describe why its important to be able to distinguish between and upper and lower motor neurone facial nerve palsy
new onset upper motor neurone facial nerve palsy you should be referring urgently with a suspected stroke, whereas patients with lower motor neurone facial nerve palsy can be reassured and managed in the community.
describe how you could tell whether a facial nerve palsy is upper or lower?
Each side of the forehead has upper motor neurone innervation by both sides of the brain. Each side of the forehead only has lower motor neurone innervation from one side of the brain.
In an upper motor neurone lesion, the forehead will be spared and the patient can move their forehead on the affected side.
In a lower motor neurone lesion, the forehead will NOT be spared and the patient cannot move their forehead on the affected side.
Unilateral upper motor lesions occur in:
(facial nerve palsy)
Cerebrovascular accidents (strokes)
Tumours
Bilateral upper motor neurone lesions are rare. They may occur in:
(facial nerve)
Pseudobulbar palsies
Motor neurone disease
cause of bells palsy?
is idiopathic, meaning there is no clear cause
how does bells palsy present?
It presents as a unilateral lower motor neurone facial nerve palsy. The majority of patients fully recover over several weeks but recovery may take up to 12 months. A third are left with some residual weakness.
regarding bells palsy if patients symptoms develop over 72 hours - what treatment should be initiated?
NICE recommends: considering prednisolone as treatment, either:
50mg for 10 days
60mg for 5 days followed by a 5-day reducing regime of 10mg a day
what must we be careful for in bells palsy?
Patients also require lubricating eye drops to prevent the eye on the affected drying out and being damaged. If they develop pain in the eye they need an ophthalmology review for exposure keratopathy. Tape can be used to keep the eye closed at night.
