Neurology - Cranial nerve damage

Paralysie de Bell | Clinique Omicron Québec

Bell's palsy is a sudden, unilateral attack of the facial nerve (7th cranial nerve), resulting in partial or complete paralysis of the muscles on one side of the face. It is the most common form of peripheral facial paralysis, with an estimated incidence of 20 to 30 cases per 100,000 people per year, affecting men and women of all ages. The exact cause remains uncertain in many cases, but reactivation of the herpes simplex virus type 1 within the geniculate ganglion is now widely recognized as a likely mechanism. Other associated triggers include pregnancy, diabetes, upper respiratory tract infections and exposure to cold. Onset is typically abrupt, reaching peak intensity in 48 to 72 hours. The prognosis is generally favourable: most patients recover normal or near-normal facial function within a few weeks to a few months, provided treatment is initiated promptly. However, a delay in treatment or an unidentified underlying cause may compromise recovery.

Important: facial paralysis and stroke

Sudden facial paralysis can be a sign of stroke. Unlike Bell's palsy, a centrally-induced paralysis usually preserves the forehead, and is often accompanied by other signs such as limb weakness, slurred speech, double vision or severe headaches.

If any of these signs are present, call 911 immediately.

Every minute counts in the event of a stroke. Don't wait to call for help.

Causes and risk factors

Bell's palsy is said to be idiopathic when no precise cause is identified. Several factors are nevertheless recognized as predisposing or triggering:

Factor	Details
Viral reactivation	Herpes simplex type 1 (HSV-1) in the majority of presumed cases; varicella-zoster virus (otic shingles or Ramsay Hunt syndrome)
Diabetes	Significantly increased risk; underlying neuropathy may weaken the facial nerve
Pregnancy	Incidence multiplied by 3 in the third trimester and in the immediate post-partum period
Immunosuppression	HIV, chemotherapy, prolonged corticosteroid therapy
Recent infections	Infection of the upper respiratory tract in the preceding weeks
Cold exposure	Triggering factor reported by many patients, although not formally confirmed
Family history	Slight genetic predisposition identified in certain families

Symptoms

The clinical picture is dominated by unilateral paralysis of the facial muscles, but other manifestations may accompany or precede the motor impairment:

Marked sagging or asymmetry on one side of the face (corner of mouth, cheek, eyebrow)
Inability to close the eye completely on the affected side (lagophthalmos)
Difficulty smiling, whistling, puffing up the cheeks or wrinkling the forehead
Retro-auricular or mastoid pain, often preceding paralysis
Hyperacusis (increased sensitivity to sound) due to damage to the stapedial muscle
Impaired taste in the anterior two-thirds of the tongue (dysgeusia)
Excessive tearing or, conversely, dry eyes
Sensation of tingling or numbness on the affected side of the face
Difficulty eating or drinking (liquids escaping from the mouth)

ℹ️ In Bell's palsy, the forehead is affected on both sides, unlike central facial paralysis (stroke) where the forehead is spared. This simple clinical distinction is essential for rapidly orienting the diagnosis and ruling out a neurological emergency.

Diagnosis

The diagnosis of Bell's palsy is primarily clinical. It is based on the exclusion of other causes of facial paralysis, notably central, infectious, tumoral or traumatic causes.

Complete neurological examination, including assessment of motor skills in the forehead, eyelids and mouth
House-Brackmann scale for grading severity of paralysis (I to VI)
Otoscopy to rule out Ramsay Hunt syndrome (herpetic vesicles in the ear canal)
Fasting blood glucose or HbA1c to check for underlying diabetes
Brain MRI with gadolinium if atypical presentation, unfavorable evolution or suspected central or tumoral cause
Serologies (Lyme, HIV, shingles) according to clinical and epidemiological context
Electromyography (EMG) in cases of persistent complete paralysis, to assess recovery prognosis

Treatments

Early treatment is crucial to optimize recovery. Treatment should ideally be initiated within 72 hours of the onset of symptoms.

Treatment	Terms and conditions	Remarks
Oral corticosteroids	Prednisone short course (10 to 14 days), started within 72 h	Reference treatment; reduces nerve inflammation and improves recovery prognosis
Oral antivirals	Acyclovir or valacyclovir in combination with corticosteroids	Additional benefit especially in cases of severe paralysis or suspected herpetic origin
Eye protection	Artificial tears during the day, ophthalmic ointment at night, palpebral occlusion if necessary.	Top priority to prevent corneal damage caused by unclosed eyes
Physiotherapy / facial rehabilitation	Facial mobilization exercises, biofeedback, massage	Recommended for persistent paralysis beyond 3 weeks
Botulinum toxin	Targeted injections for syncinesia or motor sequelae	Specialized care; indicated in the incomplete recovery phase
Decompression surgery	Otological decompression of the facial canal	Reserved for severe refractory cases; rare and controversial indication

Course and prognosis

The prognosis for Bell's palsy is generally favorable, particularly when treatment is initiated early. The main trends are as follows:

Delay	Usual course
2 to 4 weeks	Most patients begin to recover facial movements
1 to 3 months	Complete or near-complete recovery in about 70 to 85 % of cases
3 to 6 months	Partial recovery possible in severe forms; after-effects more likely
Over 6 months	Permanent sequelae (synkinesias, contractures, residual asymmetry) in 10 to 15 % of cases

ℹ️ Poor prognostic factors include complete facial paralysis at onset, advanced age, the presence of diabetes, failure to treat within the first 72 hours, and severe retroauricular pain. Regular medical follow-up enables management to be adapted if recovery is slower than expected.

Possible complications

In the absence of adequate treatment, or in severe forms, several sequelae may become permanently established:

Synkinesias: associated involuntary movements (e.g. eye blink when chewing)
Permanent facial contracture on the affected side
Residual facial asymmetry affecting body image and quality of life
Corneal damage (exposure keratitis) due to incomplete eye closure
Crocodile tears: reflex tearing during meals, linked to aberrant nerve regeneration
Homolateral or contralateral recurrence in 7 to 10 % of cases

Consult at Clinique Omicron

Clinique Omicron takes care of peripheral facial paralysis at its several points of service in Quebec. As soon as symptoms appear, a prompt medical consultation helps to confirm the diagnosis, exclude an urgent cause and initiate treatment within the optimal therapeutic window. A physician or specialized nurse practitioner (SPN) can assess the severity of the condition, prescribe the necessary tests and, if necessary, refer the patient to a neurologist or ENT specialist. In-person and telemedicine consultations are available. To book an appointment at one of our points of service or online, visit cliniqueomicron.ca.

The content of this page is provided for informational purposes only and is not intended to replace the advice of a qualified healthcare professional. Consult a physician for any symptoms, questions or decisions you may have regarding your health.

Omicron Clinic

Need to consult a doctor?

Treatment within 24-48 hours. In-clinic or telemedicine, anywhere in Quebec.

No appointment necessary Private clinic Family doctor

Insurance receipts. 7j/7. No family doctor required.

At the clinic

At home

On line

Health assessments

Our programs