Why are glucocorticoids (steroids) used to treat Bell palsy?

Glucocorticoids in Bell's Palsy Treatment

Glucocorticoids are used to treat Bell's palsy because they significantly reduce inflammation and edema of the facial nerve, leading to improved recovery rates and reduced risk of unsatisfactory outcomes. 1

Mechanism and Efficacy

Glucocorticoids work in Bell's palsy through several mechanisms:

• Anti-inflammatory action: They reduce inflammation around the facial nerve, which is believed to be a primary pathophysiological mechanism in Bell's palsy
• Reduction of edema: By decreasing swelling around the nerve, they minimize compression and subsequent nerve damage
• Prevention of neural degeneration: Early administration helps preserve nerve function

The American Academy of Otolaryngology-Head and Neck Surgery strongly recommends oral corticosteroids within the first 72 hours of symptom onset as the primary treatment for Bell's palsy, supported by high-quality evidence showing significantly improved recovery rates 1.

Treatment Protocol

Timing and Dosage

• Administration timing: Within first 72 hours of symptom onset for maximum efficacy 1
• Dosage considerations: High-dose corticosteroids (120mg prednisolone equivalent daily) appear more effective than low-dose (60mg) regimens, particularly in severe cases 2
  • In severe Bell's palsy (Yanagihara score 0-10), high-dose steroids reduced non-recovery rate by 16.1% compared to low-dose treatment 2
  • The efficacy of high-dose corticosteroids is greater when administered within 3 days of symptom onset 2

Treatment Outcomes

• Corticosteroid treatment reduces the risk of unsatisfactory recovery (relative risk 0.69,95% CI 0.55-0.87) 3
• Number needed to treat is 11 (95% CI 8-25) to prevent one case of unsatisfactory recovery 3
• Without treatment, 70-94% of patients recover completely, but up to 30% may have incomplete recovery, highlighting the importance of appropriate treatment 1

Combination Therapy Considerations

• Antiviral agents alone are not recommended as monotherapy for Bell's palsy 1
• Combination therapy (antivirals plus corticosteroids) may provide minimal additional benefit compared to corticosteroids alone (RR 0.75,95% CI 0.56-1.00) 1, 3
• A systematic review of five studies found that adding antivirals to corticosteroids did not significantly improve complete recovery rates (OR 1.03,95% CI 0.74-1.42) 4

Important Clinical Considerations

Patient Selection

• Careful evaluation of risk factors is essential before initiating steroid therapy:
  • Age
  • Comorbidities
  • Current medications
  • History of steroid response/side effects 1

Adjunctive Care

• Ocular protection is crucial for patients with incomplete eyelid closure:
  • Artificial tears
  • Ocular ointment
  • Eye patching or taping 1

Follow-up

• Patients should be reevaluated or referred to a facial nerve specialist if:
  • New neurological findings emerge
  • Symptoms worsen
  • Ocular symptoms develop
  • Incomplete facial recovery after 3 months 1

Common Pitfalls and Caveats

1. Delayed treatment: Efficacy decreases significantly when treatment is initiated beyond 72 hours after symptom onset
2. Inadequate dosing: Using insufficient doses may lead to suboptimal outcomes, particularly in severe cases
3. Overlooking ocular protection: Failure to address incomplete eye closure can lead to corneal damage
4. Unnecessary diagnostic testing: Routine laboratory tests and imaging studies are not recommended for typical Bell's palsy diagnosis 1
5. Overreliance on antivirals: Using antivirals alone without corticosteroids is not supported by evidence 1, 3

While some older studies questioned the efficacy of corticosteroids in Bell's palsy 5, more recent and comprehensive evidence strongly supports their use as the primary treatment option, particularly when administered early in the disease course.