Bell's Palsy: Definition, Signs, Causes, and Management

Bell's Palsy

Definition

Bell's palsy is defined as an idiopathic paresis or paralysis of the facial nerve of sudden onset. It is characterized as a unilateral lower motor neuron paralysis, not related to any other disease elsewhere in the body.

Signs & Symptoms

• Inability to wrinkle forehead: Loss of motor control in the frontalis muscle.

• Inability to raise eyebrow: Weakness of the occipitofrontalis muscle.

• Drooping corner of mouth: Paralysis of muscles controlling facial expression.

• Hyperacusis: Increased sensitivity to sound due to paralysis of the stapedius muscle.

• Loss of coordination (Ataxia): Difficulty in coordinated facial movements.

• Inability to close eye: Weakness of the orbicularis oculi muscle, leading to incomplete eyelid closure.

• Change in quantity of tears: Altered lacrimal gland function.

• Change in amount of saliva: Impaired salivary gland secretion.

Causes

Although Bell's palsy is idiopathic, several risk factors and associated conditions have been identified:

• Diabetes

• High Blood Pressure

• Pregnancy

• Sarcoidosis

• Myasthenia Gravis

• Herpes Zoster

Additional info: Viral infections, especially herpes simplex virus, are commonly implicated in the etiology of Bell's palsy.

Diet and Regimen

• Avoid hard chewy food: To reduce strain on weakened facial muscles.

• Try small mouthfuls: To facilitate easier chewing and swallowing.

• Brush your teeth after meals: To maintain oral hygiene, as food may accumulate due to muscle weakness.

Treatment

• Oral corticosteroids: Reduce inflammation and swelling of the facial nerve.

• Antiviral medication (e.g., Acyclovir): Used if a viral cause is suspected.

• Electrical stimulation: May help maintain muscle tone and prevent atrophy.

• Vitamin therapy: Supplementation may support nerve recovery.

Key Terms

• Paresis: Partial loss of voluntary movement or impaired movement.

• Paralysis: Complete loss of muscle function in part of the body.

• Idiopathic: Of unknown cause.

• Lower motor neuron: Refers to the motor neurons that directly innervate muscles.

Example

A patient presents with sudden onset of facial drooping on one side, inability to close the eye, and loss of the nasolabial fold. There is no evidence of stroke or other systemic disease. This clinical picture is characteristic of Bell's palsy.