16/10/2019
🍁🍁Bell's palsy 🍁🍁
✨ acute unilateral peripheral facial nerve palsy not associated with other cranial neuropathies or brainstem dysfunction.
✨It is a common disorder at all ages from infancy to adolescence & develops 2 wk after a systemic viral infection.
✨The preceding infection is caused by: 🤔
🕳️ Herpes simplex virus
🕳️varicella-zoster virus
🕳️Epstein-Barr virus
🕳️Lyme disease
🕳️Mumps virus
🕳️Toxocara
🕳️Rickettsia
🕳️MycoplasmaHIV infection
💎💎Ramsay Hunt syndrome 💎💎
(herpes zoster oticus) is associated with vesicles in the external auditory canal or auricle and an ipsilateral facial palsy.
💥💥Active or reactivation of herpes simplex or varicella-zoster virus may be the most common cause of Bell palsy .💥💥
🕳️The disease is a postinfectious ((allergic or immune)) demyelinating facial neuritis or focal toxic or inflammatory neuropathy or associated with ribavirin and interferon-α therapy for hepatitis C.
✨Hereditary forms are rare.
🌼CLINICAL MANIFESTATIONS🌼
🍭The upper and lower portions of the face are paretic
🍭the corner of the mouth droops.
🍭 Patients are unable to close the eye on the involved side and can develop an exposure keratitis at night.
🍭 Taste on the anterior 2/3 of the tongue is lost on the involved side in approximately 50% of cases.
🍭 ipsilateral numbness of the face occur in a few cases caused by viral (especially herpes) or postviral immunologic impairment of the trigeminal and the facial nerves.
🍭Pain behind the ear may precede weakness. 🍭Acute hearing loss may occur in Bell
palsy associated with(( Rickettsia infection)).
🌼IMAGING THE FACIAL NERVE AND
ITS BONY CANAL🌼
🌀((Modern high-resolution MRI))➡️ visualize the facial nerve within its canal and
detecting if bony anomalies, compressive aneurysms, vascular malformations, or nerve sheath or infiltrative tumors that might explain a palsy anatomically.
🌀((Ultrasound ))of the facial nerve as a predictor of functional outcome in Bell palsy.
More recently,
🌀((diffusion tensor tractography)) ➡️enables a tridimensional display of facial nerve axons.
🌼TREATMENT🌼
🍂🍂Oral prednisone (1 mg/kg/day for 1 wk, followed by a 1 wk taper)
started within the 1st 3-5 days results in improved outcome and is a
traditional treatment.
🍂🍂adding oral acyclovir or valacyclovir to the prednisone therapy
🌠 Alone antiviral agents are not effective in reducing adverse sequelae (synkinesis, autonomic dysfunction), but added to predni-
sone may be associated with an additional small benefit.
🍂 🍂Surgical decompression of the facial canal, to provide more space for the swollen facial
nerve, is not of value unless imaging provides evidence of nerve compression or an anatomic lesion
🍂🍂Traditional physiotherapy to the facial muscles is recommended in some chronic cases with poor recovery, but the efficacy of
this treatment is uncertain.
🍂🍂 Protection of the cornea with methylcellulose eyedrops or an ocular lubricant is especially important at night.
🍂🍂Botulinum toxin has been applied in adults to the contralateral normal facial muscles for cosmetic purposes to minimize the apparent asymmetry or to treat chronic unilateral ptosis.
🌼PROGNOSIS🌼
🎯The prognosis for functional recovery is excellent.
🎯More than 85% of patients recover spontaneously with no residual facial weakness.
🎯Another 10% have mild facial weakness as a sequela, a mild facial asymmetry.
🎯only 5% are left with permanent severe facial weakness.
💎💎In patients who do not recover within a few weeks (chronic), electrophysiologic examination of the facial nerve helps to determine the degree of neuropathy and regeneration.💎💎
🌻🌻In chronic cases➡️➡️ other causes of facial neuropathy should be considered as :
🍁 Facial nerve tumors such as schwannomas and neurofibromas
🍁 Infiltration of the facial nerve by leukemic cells or by a rhabdomyosarcoma of the middle ear,
🍁 Brainstem infarcts or tumors.
🍁Traumatic injury of the facial nerve.
Nelson 20