Bell’s palsy

Definition:

• Bell’s Palsy is a form of temporary facial paralysis or weakness on one side of the face due to dysfunction of the facial nerve (cranial nerve VII).

Epidemiology:

• Most common cause of facial paralysis.
• Can occur at any age, but more common between ages 15 and 60.
• No significant gender difference in incidence.

Etiology:

• Exact cause is often unknown.
• Thought to be associated with viral infections, particularly the herpes simplex virus.

Pathophysiology:

• Inflammation and swelling of the facial nerve, likely due to a viral infection, leading to compression and ischemia within the narrow fallopian canal.

Clinical Features:

• Sudden onset of unilateral facial weakness or paralysis.
• Inability to raise eyebrow, smile, or close eye on the affected side.
• Loss of forehead creases.
• May have altered taste, hyperacusis (increased sensitivity to sound), or decreased tear and saliva production on the affected side.

Diagnosis:

• Clinical diagnosis based on history and physical examination.
• No specific tests are usually required, but imaging (like MRI) may be done to rule out other causes in atypical cases.

Management:

• Most cases spontaneously recover within weeks to months.
• Corticosteroids are often prescribed to reduce nerve inflammation.
• Eye care to prevent dryness and injury to the cornea (e.g., artificial tears, eye patch).
• Physiotherapy for facial muscle exercises.

Prognosis:

• Good prognosis; most patients recover completely, especially if treatment is started early.
• Some may have residual facial weakness, synkinesis (involuntary movements), or contractures.