bell palsy is an acute unilateral facial nerve palsy that is not associated with other cranial neuropathies or brain-stem dysfunctions. Bell palsy is the most common acute mononeuropathy. Incidence is 2.7 per 100000 in children less than 10 years of age.
Etiology of Bell palsy:
Infection by Herpes simplex virus, varicella-zoster virus, Epstein Barr virus, coxsackievirus, influenza, mumps, and Ramsy Hunt syndrome.
Others: Lyme disease, Mobius syndrome, trauma, metabolic syndrome, hyperparathyroidism, hypothyroidism, GBS< Myasthenia gravis.
In virus infection, viral reactivation followed by replication within the ganglion cells leads to inflammation of Schwann cells. Ultimately an autonomic response leads to demyelination and hypofunction of the involved nerve.
Clinical Features of Bell Palsy:
Patients usually present with no wrinkling of the forehead or unable to frown.
Facial deviation to one side.
Facial numbness, watering from eyes, partially open eyes. The eyeball rolled upwards during attempted forced closure known as Bell’s phenomenon.
Drooping of the angle of the mouth and flattening of the nasolabial folds while showing teeth. Can not whistle when asked to do so. There was an easy escape of air from the blown-out right cheek.
Patients usually have a history of preceding viral infection.
On examination, vital signs and Anthropometry are usually normal. Look for Rash in pinna that may lead to Ramsay Hunt Syndrome.
Motor function tests are done to tests for facial nerve palsy.
Sensory: Test for sensation in anterior two-third on the tongue is usually lost.
Investigations for Bell Palsy:
Usually, no test is required to diagnose bell palsy. The diagnosis is clinical. If there is suspicion tests can be done.
CSF study is done if meningitis is suspected.
MRI of the Brain if bilateral facial nerve palsy present.
Counseling about the nature and future of the disease. It is likely to improve in 85% cases, 10% have mild facial nerver weakness and only 5% have a severe facial weakness.
Care of eye by Artificial tear (methylcellulose eye drop for lubrication) eye closure with sellotape at night.
Steroid Prednisolone (1-2 mg/kg/day) for 1 week then taper over next week.
Acyclovir orally for 10 days.
Antibiotics if otitis media present.