Bell’s palsy


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Bell’s palsy

Acute peripheral paralysis of the face due to a herpes simplex immune-mediated condition, often characterised by severe pain arising in the trigeminal nerve, the chief sensory nerve of the face, which arises in cranial nerve VII.
 
Clinical findings
Abrupt onset, drooping mouth, unblinking eye, twisted nose, uneven smile, distorted expressions; paralysis hits maximum in 1 to 14 days; retroauricular pain, facial numbness, epiphora, parageusia, decreased tearing, hyperacusis, hypoesthesia or dysesthesia of cranial nerves (CN V and IX), motor paresis of CN IX and X, papillitis of tongue.
 
Epidemiology
Risk of Bell’s palsy increases with age; age 10 to 19, 2:1 female:male ratio; age 40, 3:2 men:women ratio; pregnant women have 3.3 times increased risk than nonpregnant; DM = 4.5 times increased risk of BP; 10% of patients have positive family Hx of BP.
 
DiffDx, unilateral
Tumours or masses, otitis media, sarcoid, Lyme disease, skull fracture, facial injury.
 
DiffDx, bilateral
Guillain-Barré syndrome, Melkersson-Rosenthal syndrome, Möbius syndrome, motor neuron disease, myasthenia gravis.

Aetiology
Trauma, Bell’s palsy, stroke, parotid tumours, intracranial tumours.
 
Management
Microvascular and micro-neurosurgical tissue transfers allow restoration of functional, unconscious, symmetrical facial movements; acyclovir; steroids (uncertain efficacy); artificial tears; neuromuscular retraining—e.g., mirror/visual feedback, biofeedback or electromyography feedback.
 
Prognosis
60 to 80% recover, especially if incomplete paralysis, and patient is young.