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Resúmenes Epistemonikos
Medwave 2015;15(Suppl 2):e6226 doi: 10.5867/medwave.2015.6226
¿Es útil agregar antivirales a los corticoides en la parálisis de Bell en adultos?
Is there benefit adding antivirals to corticosteroids for Bell’s palsy in adults?
Benjamín Walbaum, Gabriel Rada
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Abstract

Bell’s palsy is the first cause of unilateral facial palsy. The likely etiologic mechanism is facial nerve inflammation secondary to viral reactivation, most probably due to herpes simplex and Varicella Zoster. Corticosteroids are considered the mainstay of treatment, but it is not clear whether adding antivirals would further increase the benefit. Searching in Epistemonikos database, which is maintained by screening 30 databases, we identified 10 systematic reviews including 15 pertinent randomized controlled trials overall. We combined the evidence and generated a summary of findings following the GRADE approach. We concluded that adding antivirals to the treatment with corticosteroids probably reduces the risk of incomplete recovery in patients with Bell’s palsy.


 
Problem

Bell’s palsy consitutes the main cause of unilateral facial paralysis. Although most patients recover spontaneously, it leads to important limitations in some individuals. Herpes family reactivation by either herpes simplex or varicella zoster is accepted as the main etiology. It produces an inflammatory process that derives in edema of the perineural layer, myelin degeneration and inflammatory cells infiltration. It is not clear if adding antivirals, such as acyclovir and valacyclovir, to the standard treatment with corticosteroids would offer additional benefit.

Methods

We used Epistemonikos database, which is maintained by screening more than 30 databases, to identify systematic reviews and their included primary studies. With this information we generated a structured summary using a pre-established format, which includes key messages, a summary of the body of evidence (presented as an evidence matrix in Epistemonikos), meta-analysis of the total of studies, a summary of findings table following the GRADE approach and a table of other considerations for decision-making.

Key messages

  • Adding antivirals to the treatment with corticosteroids probably reduces the risk of incomplete recovery in patients with Bell’s palsy
About the body of evidence for this question

What is the evidence.
See evidence matrix  in Epistemonikos later

We found 10 systematic reviews [1],[2],[3],[4],[5],[6],[7],[8],[9],[10] that consider 19 pertinent studies overall [11],[12],[13],[14],[15],[16],[17],[18],[19],[20],[21],[22],
[23],[24],[25],[26],[27],[28],[29], including 16 randomized controlled trials [11],[12],[13],[14],[15],[16],[17],[18],
[19],[20],[21],[22],[23],[24],[26],[28]. This table and the summary in general are based on the latter.

What types of patients were included

All studies included adults with Bell’s Palsy diagnosed at different stages. Some studies did include patients based on severity according to House-Brackmann score.

What types of interventions were included

Seven studies included antiviral treatment using acyclovir [11],[12],[17],[18],[22],[24],[28], six valacyclovir [13],[14],[15],[16],[23],[26] and two famcyclovir [19],[21]. In five of the included studies antiviral treatment was added to prednisone [12],[15],[19],[23],[24], in nine to prednisolone [11],[14],[16],[17],[18],[21],[22],[26],[28], and in one to deflazacort [13].

All studies compared against corticosteroids monotherapy in the same dose than comparison group.

What types of outcomes
were measured

Main outcome:  Long term complete recovery of facial mobility

Other outcomes: reduction of recovery time in patients with severe palsy, short term complete mobility recovery, synkinesis, autonomic dysfunction and antiviral adverse effects

Summary of findings

The information on the effects of adding antivirals to steroidal treatment for Bell’s palsy is based on 15 randomized studies including 2592 patients [11],[12],[13],[14],[15],[16],[17],[18],[19],[20],[21],[22],[23],[24],[25],[26],[27],[28]. All studies reported the outcome incomplete recovery.

  • Adding antivirals to the treatment with corticosteroids probably reduces the risk of incomplete recovery in patients with Bell’s palsy. The certainty of the evidence is moderate.

Other considerations for decision-making

To whom this evidence does and does not apply

  • This evidence applies to adult patients diagnosed with peripheral facial palsy, regardless of severity, without need of microbiological confirmation of viral reactivation, which is similar to daily practice where diagnose is solely based on clinical findings.
  • All studies started treatment before the fourth day of symptoms, so it is unclear if we can apply these results to patients with a longer symptomatic period. If combined treatment is still used, less favorable results should be expected
About the outcomes included in this summary
  • The summarised outcome (complete facial mobility recovery) is the only outcome considered to be critical for decision making in clinical practice, based on the opinion of the authors of this summary. It is also the main outcome according to all of the systematic reviews identified. Antivirals adverse effects are not presented in the summary of findings table because of the vast evidence confirming their safety in other conditions. 
Balance between benefits and risks, and certainty of the evidence
  • Combined treatment presents a substantial benefit with minimal adverse effects, with moderate certainty of the evidence. The balance between benefits and risk is favourable.
Resource considerations
  • Adding antivirals is a low cost measure, so the cost/benefit is probably favourable. Even more if we take into account the impact that short and long term complications derived from Bell’s palsy produce on affected patients.

Differences between this summary and other sources

  • The conclusions of this summary agree with the results of the higher quality systematic reviews [4],[5] even though they put less emphasis on the benefits of combined therapy. Probably this difference can be explained by some studies that were not identified, or were not available when these were published.
  • The conclusions of this summary partially agree with the main guidelines which make a weak recommendation  for its use [30],[31].  It is important to consider these guidelines are based on a small proportion of the evidence identified in this summary, mainly because it was not available at the time of their publication.
Could this evidence change in the future?
  • The probability of future evidence modifying these conclusions is low because of the certainty of existing evidence.

How we conducted this summary

Using automated and collaborative means, we compiled all the relevant evidence for the question of interest and we present it as a matrix of evidence.

Matrix of evidence (static version).

Follow the link to access the interactive version: Antiviral agents added to corticosteroids versus corticosteroids alone for Bell's palsy in adults

Notes

The upper portion of the matrix of evidence will display a warning of “new evidence” if new systematic reviews are published after the publication of this summary. Even though the project considers the periodical update of these summaries, users are invited to comment in Medwave or to contact the authors through email if they find new evidence and the summary should be updated earlier. After creating an account in Epistemonikos, users will be able to save the matrixes and to receive automated notifications any time new evidence potentially relevant for the question appears.

The details about the methods used to produce these summaries are described here http://dx.doi.org/10.5867/medwave.2014.06.5997.

Epistemonikos foundation is a non-for-profit organization aiming to bring information closer to health decision-makers with technology. Its main development is Epistemonikos database (www.epistemonikos.org).

These summaries follow a rigorous process of internal peer review.

Conflicts of interest
The authors do not have relevant interests to declare.

Matrix of evidence (static version).
Licencia Creative Commons Esta obra de Medwave está bajo una licencia Creative Commons Atribución-NoComercial 3.0 Unported. Esta licencia permite el uso, distribución y reproducción del artículo en cualquier medio, siempre y cuando se otorgue el crédito correspondiente al autor del artículo y al medio en que se publica, en este caso, Medwave.

 

Bell’s palsy is the first cause of unilateral facial palsy. The likely etiologic mechanism is facial nerve inflammation secondary to viral reactivation, most probably due to herpes simplex and Varicella Zoster. Corticosteroids are considered the mainstay of treatment, but it is not clear whether adding antivirals would further increase the benefit. Searching in Epistemonikos database, which is maintained by screening 30 databases, we identified 10 systematic reviews including 15 pertinent randomized controlled trials overall. We combined the evidence and generated a summary of findings following the GRADE approach. We concluded that adding antivirals to the treatment with corticosteroids probably reduces the risk of incomplete recovery in patients with Bell’s palsy.

Autores: Benjamín Walbaum[1,2], Gabriel Rada[2,3,4,5]

Filiación:
[1] Departamento Urgencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
[2] Proyecto Epistemonikos
[3] Programa de Salud Basada en Evidencia, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
[4] GRADE working group
[5] The Cochrane Collaboration

E-mail: adagabriel@gmail.com

Correspondencia a:
[1] Facultad de Medicina
Pontificia Universidad Católica de Chile
Lira 63
Santiago Centro
Chile

Citación: Walbaum B, Rada G. Is there benefit adding antivirals to corticosteroids for Bell’s palsy in adults?. Medwave 2015;15(Suppl 2):e6226 doi: 10.5867/medwave.2015.6226

Fecha de publicación: 21/8/2015

Ficha PubMed

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  1. Alberton DL, Zed PJ. Bell's palsy: a review of treatment using antiviral agents. Ann Pharmacother. 2006 Oct;40(10):1838-42. Epub 2006 Sep 12. | PubMed |
  2. Dong Y, Zhu Y, Ma C, Zhao H. Steroid-antivirals treatment versus steroids alone for the treatment of Bell's palsy: a meta-analysis. Int J Clin Exp Med. 2015 Jan 15;8(1):413-21. | PubMed |
  3. Salinas RA, Alvarez G, Daly F, Ferreira J. Corticosteroids for Bell's palsy (idiopathic facial paralysis). Cochrane Database Syst Rev. 2010 Mar 17;(3):CD001942. | CrossRef | PubMed |
  4. de Almeida JR, Al Khabori M, Guyatt GH, Witterick IJ, Lin VY, Nedzelski JM, et al. Combined corticosteroid and antiviral treatment for Bell palsy: a systematic review and meta-analysis. JAMA. 2009 Sep 2;302(9):985-93. | CrossRef | PubMed |
  5. Gagyor I, Madhok VB, Daly F, Somasundara D, Sullivan M, Gammie F, et al. Antiviral treatment for Bell's palsy (idiopathic facial paralysis). Cochrane Database Syst Rev. 2015 Jul 1;7:CD001869. | PubMed |
  6. Goudakos JK, Markou KD. Corticosteroids vs corticosteroids plus antiviral agents in the treatment of Bell palsy: a systematic review and meta-analysis. Arch Otolaryngol Head Neck Surg. 2009 Jun;135(6):558-64. | CrossRef | PubMed |
  7. Gronseth GS, Paduga R; American Academy of Neurology. Evidence-based guideline update: steroids and antivirals for Bell palsy: report of the Guideline Development Subcommittee of the American Academy of Neurology. Neurology. 2012 Nov 27;79(22):2209-13. | CrossRef | PubMed |
  8. Numthavaj P, Thakkinstian A, Dejthevaporn C, Attia J. Corticosteroid and antiviral therapy for Bell's palsy: a network meta-analysis. BMC Neurol. 2011 Jan 5;11:1. | CrossRef | PubMed |
  9. Quant EC, Jeste SS, Muni RH, Cape AV, Bhussar MK, Peleg AY. The benefits of steroids versus steroids plus antivirals for treatment of Bell's palsy: a meta-analysis. BMJ. 2009 Sep 7;339:b3354. | CrossRef | PubMed |
  10. van der Veen EL, Rovers MM, de Ru JA, van der Heijden GJ. A small effect of adding antiviral agents in treating patients with severe Bell palsy. Otolaryngol Head Neck Surg. 2012 Mar;146(3):353-7. | CrossRef | PubMed |
  11. Abdelghany AM, Kamel SB. The effect of prednisolone and/or acyclovir in relation to severity of Bell’s palsy at presentation. Egypt J Ear Nose Throat and Allied Scienc. 2013;14(3):155-9. | CrossRef |
  12. Adour KK, Ruboyianes JM, Von Doersten PG, Byl FM, Trent CS, Quesenberry CP Jr, et al. Bell's palsy treatment with acyclovir and prednisone compared with prednisone alone: a double-blind, randomized, controlled trial. Ann Otol Rhinol Laryngol. 1996 May;105(5):371-8. | PubMed |
  13. Antunes LM, Fukuda Y, Testa JRG. Clinical treatment of Bell's palsy: comparative study with the use of valaciclovir more deflazacort versus deflazacort versus placebo. Acta AWHO. 2000 2000;19(2):68-75. | Link |
  14. Engström M1, Berg T, Stjernquist-Desatnik A, Axelsson S, Pitkäranta A, Hultcrantz M, et al. Prednisolone and valaciclovir in Bell's palsy: a randomised, double-blind, placebo-controlled, multicentre trial. Lancet Neurol. 2008 Nov;7(11):993-1000. | CrossRef | PubMed |
  15. Hato N, Yamada H, Kohno H, Matsumoto S, Honda N, Gyo K,et al. Valacyclovir and prednisolone treatment for Bell's palsy: a multicenter, randomized, placebo-controlled study. Otol Neurotol. 2007 Apr;28(3):408-13. | PubMed |
  16. Kawaguchi K, Inamura H, Abe Y, Koshu H, Takashita E, Muraki Y, et al. Reactivation of herpes simplex virus type 1 and varicella-zoster virus and therapeutic effects of combination therapy with prednisolone and valacyclovir in patients with Bell's palsy. Laryngoscope. 2007 Jan;117(1):147-56. | PubMed |
  17. Lee HY, Byun JY, Park MS, Yeo SG. Steroid-antiviral treatment improves the recovery rate in patients with severe Bell's palsy. Am J Med. 2013 Apr;126(4):336-41. | CrossRef | PubMed |
  18. Li Y-j, Gao P-f, Mao X-l, Pei-ye C. Randomized clinical trial of acyclovir plus prednisone versus prednisone alone in Bell's Palsy. The Ceylon Journal of Medical Science. 1997 1997;40(2):37-41. | Link |
  19. Minnerop M, Herbst M, Fimmers R, Kaabar P, Matz B, Klockgether T, et al. Bell's palsy: combined treatment of famciclovir and prednisone is superior to prednisone alone. J Neurol. 2008 Nov;255(11):1726-30. | CrossRef | PubMed |
  20. Roy A, Jose J, Kamath V, Matthew T. Efficacy of acyclovir and methylprednisolone versus methylprednisolone alone in the treatment of bell's palsy. XVIIIth World Congress of Neurology; 2005. | CrossRef |
  21. Shahidullah M, Haque A, Islam MR, Rizvi AN, Sultana N, Mia BA, et al. Comparative study between combination of famciclovir and prednisolone with prednisolone alone in acute Bell's palsy. Mymensingh Med J. 2011 Oct;20(4):605-13. | PubMed |
  22. Sullivan FM, Swan IR, Donnan PT, Morrison JM, Smith BH, McKinstry B, et al. Early treatment with prednisolone or acyclovir in Bell's palsy. N Engl J Med. 2007 Oct 18;357(16):1598-607. | PubMed |
  23. Vázquez MC, Sánchez N, Calvo J, Perna A. Efficacy of antivirals in Bell's palsy. Rev Med Uruguay. 2008 2008;24(3):1-8. | Link |
  24. Yeo SG, Lee YC, Park DC, Cha CI. Acyclovir plus steroid vs steroid alone in the treatment of Bell's palsy. Am J Otolaryngol. 2008 May-Jun;29(3):163-6. | CrossRef | PubMed |
  25. Ahangar AA, Hosseini S, Saghebi R. Comparison of the efficacy of prednisolone versus prednisolone and acyclovir in the treatment of Bell`s palsy. Neurosciences (Riyadh). 2006 Oct;11(4):256-9. | PubMed |
  26. Axelsson S, Berg T, Jonsson L, Engström M, Kanerva M, Stjernquist-Desatnik A. Bell's palsy - the effect of prednisolone and/or valaciclovir versus placebo in relation to baseline severity in a randomised controlled trial. Clin Otolaryngol. 2012 Aug;37(4):283-90. | CrossRef | PubMed |
  27. Hato N, Matsumoto S, Kisaki H, Takahashi H, Wakisaka H, Honda N,et al. Efficacy of early treatment of Bell's palsy with oral acyclovir and prednisolone. Otol Neurotol. 2003 Nov;24(6):948-51. | PubMed |
  28. İnanlı S, Tutkun A, Öztürk O, Batman Ç, Üneri C, Şehitoğlu MA. Idiopathic Facial Nerve Paralysis Treatment with Acyclovir and Prednisolone Compared with Prednisolone Alone. Türk Otolarengoloji Arflivi (Turkish Archives of Otorhinolaryngology). 2001 2001;39(1):19-24. | Link |
  29. Tang IP, Lee SC, Shashinder S, Raman R. Outcome of patients presenting with idiopathic facial nerve paralysis (Bell's palsy) in a tertiary centre--a five year experience. Med J Malaysia. 2009 Jun;64(2):155-8. | PubMed |
  30. Baugh RF, Basura GJ, Ishii LE, Schwartz SR, Drumheller CM, Burkholder R, et al. Clinical practice guideline: Bell's palsy. Otolaryngol Head Neck Surg. 2013 Nov;149(3 Suppl):S1-27. | CrossRef | PubMed |
  31. Gronseth GS, Paduga R; American Academy of Neurology. Evidence-based guideline update: steroids and antivirals for Bell palsy: report of the Guideline Development Subcommittee of the American Academy of Neurology. Neurology. 2012 Nov 27;79(22):2209-13. | CrossRef | PubMed |
Alberton DL, Zed PJ. Bell's palsy: a review of treatment using antiviral agents. Ann Pharmacother. 2006 Oct;40(10):1838-42. Epub 2006 Sep 12. | PubMed |

Dong Y, Zhu Y, Ma C, Zhao H. Steroid-antivirals treatment versus steroids alone for the treatment of Bell's palsy: a meta-analysis. Int J Clin Exp Med. 2015 Jan 15;8(1):413-21. | PubMed |

Salinas RA, Alvarez G, Daly F, Ferreira J. Corticosteroids for Bell's palsy (idiopathic facial paralysis). Cochrane Database Syst Rev. 2010 Mar 17;(3):CD001942. | CrossRef | PubMed |

de Almeida JR, Al Khabori M, Guyatt GH, Witterick IJ, Lin VY, Nedzelski JM, et al. Combined corticosteroid and antiviral treatment for Bell palsy: a systematic review and meta-analysis. JAMA. 2009 Sep 2;302(9):985-93. | CrossRef | PubMed |

Gagyor I, Madhok VB, Daly F, Somasundara D, Sullivan M, Gammie F, et al. Antiviral treatment for Bell's palsy (idiopathic facial paralysis). Cochrane Database Syst Rev. 2015 Jul 1;7:CD001869. | PubMed |

Goudakos JK, Markou KD. Corticosteroids vs corticosteroids plus antiviral agents in the treatment of Bell palsy: a systematic review and meta-analysis. Arch Otolaryngol Head Neck Surg. 2009 Jun;135(6):558-64. | CrossRef | PubMed |

Gronseth GS, Paduga R; American Academy of Neurology. Evidence-based guideline update: steroids and antivirals for Bell palsy: report of the Guideline Development Subcommittee of the American Academy of Neurology. Neurology. 2012 Nov 27;79(22):2209-13. | CrossRef | PubMed |

Numthavaj P, Thakkinstian A, Dejthevaporn C, Attia J. Corticosteroid and antiviral therapy for Bell's palsy: a network meta-analysis. BMC Neurol. 2011 Jan 5;11:1. | CrossRef | PubMed |

Quant EC, Jeste SS, Muni RH, Cape AV, Bhussar MK, Peleg AY. The benefits of steroids versus steroids plus antivirals for treatment of Bell's palsy: a meta-analysis. BMJ. 2009 Sep 7;339:b3354. | CrossRef | PubMed |

van der Veen EL, Rovers MM, de Ru JA, van der Heijden GJ. A small effect of adding antiviral agents in treating patients with severe Bell palsy. Otolaryngol Head Neck Surg. 2012 Mar;146(3):353-7. | CrossRef | PubMed |

Abdelghany AM, Kamel SB. The effect of prednisolone and/or acyclovir in relation to severity of Bell’s palsy at presentation. Egypt J Ear Nose Throat and Allied Scienc. 2013;14(3):155-9. | CrossRef |

Adour KK, Ruboyianes JM, Von Doersten PG, Byl FM, Trent CS, Quesenberry CP Jr, et al. Bell's palsy treatment with acyclovir and prednisone compared with prednisone alone: a double-blind, randomized, controlled trial. Ann Otol Rhinol Laryngol. 1996 May;105(5):371-8. | PubMed |

Antunes LM, Fukuda Y, Testa JRG. Clinical treatment of Bell's palsy: comparative study with the use of valaciclovir more deflazacort versus deflazacort versus placebo. Acta AWHO. 2000 2000;19(2):68-75. | Link |

Engström M1, Berg T, Stjernquist-Desatnik A, Axelsson S, Pitkäranta A, Hultcrantz M, et al. Prednisolone and valaciclovir in Bell's palsy: a randomised, double-blind, placebo-controlled, multicentre trial. Lancet Neurol. 2008 Nov;7(11):993-1000. | CrossRef | PubMed |

Hato N, Yamada H, Kohno H, Matsumoto S, Honda N, Gyo K,et al. Valacyclovir and prednisolone treatment for Bell's palsy: a multicenter, randomized, placebo-controlled study. Otol Neurotol. 2007 Apr;28(3):408-13. | PubMed |

Kawaguchi K, Inamura H, Abe Y, Koshu H, Takashita E, Muraki Y, et al. Reactivation of herpes simplex virus type 1 and varicella-zoster virus and therapeutic effects of combination therapy with prednisolone and valacyclovir in patients with Bell's palsy. Laryngoscope. 2007 Jan;117(1):147-56. | PubMed |

Lee HY, Byun JY, Park MS, Yeo SG. Steroid-antiviral treatment improves the recovery rate in patients with severe Bell's palsy. Am J Med. 2013 Apr;126(4):336-41. | CrossRef | PubMed |

Li Y-j, Gao P-f, Mao X-l, Pei-ye C. Randomized clinical trial of acyclovir plus prednisone versus prednisone alone in Bell's Palsy. The Ceylon Journal of Medical Science. 1997 1997;40(2):37-41. | Link |

Minnerop M, Herbst M, Fimmers R, Kaabar P, Matz B, Klockgether T, et al. Bell's palsy: combined treatment of famciclovir and prednisone is superior to prednisone alone. J Neurol. 2008 Nov;255(11):1726-30. | CrossRef | PubMed |

Roy A, Jose J, Kamath V, Matthew T. Efficacy of acyclovir and methylprednisolone versus methylprednisolone alone in the treatment of bell's palsy. XVIIIth World Congress of Neurology; 2005. | CrossRef |

Shahidullah M, Haque A, Islam MR, Rizvi AN, Sultana N, Mia BA, et al. Comparative study between combination of famciclovir and prednisolone with prednisolone alone in acute Bell's palsy. Mymensingh Med J. 2011 Oct;20(4):605-13. | PubMed |

Sullivan FM, Swan IR, Donnan PT, Morrison JM, Smith BH, McKinstry B, et al. Early treatment with prednisolone or acyclovir in Bell's palsy. N Engl J Med. 2007 Oct 18;357(16):1598-607. | PubMed |

Vázquez MC, Sánchez N, Calvo J, Perna A. Efficacy of antivirals in Bell's palsy. Rev Med Uruguay. 2008 2008;24(3):1-8. | Link |

Yeo SG, Lee YC, Park DC, Cha CI. Acyclovir plus steroid vs steroid alone in the treatment of Bell's palsy. Am J Otolaryngol. 2008 May-Jun;29(3):163-6. | CrossRef | PubMed |

Ahangar AA, Hosseini S, Saghebi R. Comparison of the efficacy of prednisolone versus prednisolone and acyclovir in the treatment of Bell`s palsy. Neurosciences (Riyadh). 2006 Oct;11(4):256-9. | PubMed |

Axelsson S, Berg T, Jonsson L, Engström M, Kanerva M, Stjernquist-Desatnik A. Bell's palsy - the effect of prednisolone and/or valaciclovir versus placebo in relation to baseline severity in a randomised controlled trial. Clin Otolaryngol. 2012 Aug;37(4):283-90. | CrossRef | PubMed |

Hato N, Matsumoto S, Kisaki H, Takahashi H, Wakisaka H, Honda N,et al. Efficacy of early treatment of Bell's palsy with oral acyclovir and prednisolone. Otol Neurotol. 2003 Nov;24(6):948-51. | PubMed |

İnanlı S, Tutkun A, Öztürk O, Batman Ç, Üneri C, Şehitoğlu MA. Idiopathic Facial Nerve Paralysis Treatment with Acyclovir and Prednisolone Compared with Prednisolone Alone. Türk Otolarengoloji Arflivi (Turkish Archives of Otorhinolaryngology). 2001 2001;39(1):19-24. | Link |

Tang IP, Lee SC, Shashinder S, Raman R. Outcome of patients presenting with idiopathic facial nerve paralysis (Bell's palsy) in a tertiary centre--a five year experience. Med J Malaysia. 2009 Jun;64(2):155-8. | PubMed |

Baugh RF, Basura GJ, Ishii LE, Schwartz SR, Drumheller CM, Burkholder R, et al. Clinical practice guideline: Bell's palsy. Otolaryngol Head Neck Surg. 2013 Nov;149(3 Suppl):S1-27. | CrossRef | PubMed |

Gronseth GS, Paduga R; American Academy of Neurology. Evidence-based guideline update: steroids and antivirals for Bell palsy: report of the Guideline Development Subcommittee of the American Academy of Neurology. Neurology. 2012 Nov 27;79(22):2209-13. | CrossRef | PubMed |