Patients with new-onset Bell palsy have a high likelihood of recovering facial nerve function with steroids alone, according to a clinical guideline update from the American Academy of Neurology (AAN).

Adding an antiviral agent to steroids has a low probability of improving nerve function over steroids alone. However, clinicians can offer patients antiviral therapy with the understanding that any improvement will likely be modest at best, authors of the clinical update stated in an article published online in Neurology.

Moreover, individual patient circumstances should figure into the decision to use steroids, they said.

“Although there is strong evidence that steroid use increases the probability of good facial functional recovery in patients with Bell palsy, it does not necessarily follow that all patients with Bell palsy need to take steroids,” wrote Gary Gronseth, MD, and Remia Paduga, MD, of the University of Kansas in Kansas City.

“For example, it would be reasonable for a clinician to opt not to use steroids in a patient with brittle diabetes mellitus. Other comorbidities potentially requiring further consideration include morbid obesity, osteopenia, and a prior history of steroid intolerance,” they added.

With an annual incidence of 20 per 100,000, Bell palsy has an acute onset of unidentified origin. In most cases, the characteristic facial paresis resolves with or without treatment, but as many as 30% of patients do not recover full facial function.

In a clinical guideline issued in 2001, the AAN concluded that steroids are “probably effective” and antivirals (specifically, acyclovir) “possibly effective” in improving the odds of complete recovery of facial function in patients with Bell palsy.

The update incorporates relevant information published since 2000. The authors focused specifically on new information related to use of steroids and antivirals in new-onset Bell palsy.

Relevant studies had been published as full-text articles, involved at least 20 patients with new-onset Bell palsy, and had at least 3 months’ follow-up to determine facial functional recovery. The final data synthesis comprised nine published articles related to steroid treatment and eight related to use of antivirals.

The authors limited their discussion to class I and II studies (highest levels of evidence).

Two class I studies of steroids demonstrated significant increases in the probability of complete recovery of facial function, whereas none of three class II studies showed a benefit. The improvement was associated with a number needed to treat of six to eight.

Adverse events were similar, mild, and transient across the studies.

“For patients with new-onset Bell palsy, it is highly likely that steroids are effective in increasing the probability of complete facial functional recovery,” the authors wrote.

Five of the eight studies of antivirals were rated class IV because of deficiencies in design. Neither of two class I studies demonstrated significant improvement with antivirals versus placebo. The studies included only patients who already were on steroids.

Pooled analysis of the two studies yielded 95% confidence intervals that did not exclude the possibility of as much as a benefit from the addition of an antiviral. Inclusion of the class II studies did not appreciably improve the study precision.

None of the studies showed a significant increase in adverse events associated with antiviral therapy.

“For patients with acute-onset Bell palsy, it is highly likely that antivirals do not moderately increase the likelihood of improved facial functional recovery,” the authors wrote in conclusion. “The pooled results of studies with a low risk of bias lack the statistical precision to exclude a modest benefit or modest harm.”

In their summary recommendations, the authors wrote that “oral steroids should be offered to increase the probability of recovery of facial nerve function.”

“For patients with new-onset Bell palsy, antivirals (in addition to steroids) might be offered to increase the probability of recovery of facial function. Patients offered antivirals should be counseled that a benefit from antivirals has not been established, and, if there is a benefit, it is likely that it is modest at best.”

With regard to directions for future research, Gronseth and Paduga wrote that “it is unlikely that additional research regarding the efficacy of steroids will change the current estimate of its effect.

“Large randomized trials comparing outcomes in patients with Bell palsy receiving steroids with or without antivirals would help in determining whether the addition of antivirals to steroid treatment results in a modest benefit,” they said.

The research was supported by the American Academy of Neurology.

Gronseth disclosed a relationship with Boehringer Ingelheim.

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Primary source: Neurology
Source reference: Gronseth GS, Paduga R “Evidence-based guideline update: Steroids and antivirals for Bell palsy: Report of the guideline development subcommittee of the American Academy of Neurology” Neurology 2012; DOI: 10.1212/WNL.0b013e318275978c.