EM@3AM – Bell’s Palsy

Author: Erica Simon, DO, MHA (@E_M_Simon, EM Chief Resident, SAUSHEC, USAF) // Edited by: Alex Koyfman, MD (@EMHighAK, EM Attending Physician, UT Southwestern Medical Center / Parkland Memorial Hospital) and Brit Long, MD (@long_brit, EM Attending Physician, SAUSHEC, USAF)

Welcome to EM@3AM, an emdocs series designed to foster your working knowledge by providing an expedited review of clinical basics. We’ll keep it short, while you keep that EM brain sharp.

A 27-year-old female with no previous medical history presents to the emergency department for “difficulty drinking.” The patient notes beverages as “falling out of the corner of her mouth” since awakening. She denies recent illness, difficulty speaking, vision deficits, loss of motor or sensory function, and recent travel. Physical examination is remarkable for a prominent right-sided facial droop with forehead involvement.

What do you suspect as a diagnosis? What’s the next step in your evaluation and treatment?

Answer: Bell’s Palsy1-4

  • Presentation:1 Facial paralysis which may be associated with otalgia, dysesthesia of the involved side of the face, decreased tearing or epiphora of the involved eye, hyperacusis, or dysguesia.
  • Pathophysiology:1,2
    • Long thought to occur secondary to a viral etiology.
    • Bilateral Bell’s Palsy => commonly the result of systemic infection.
      • Consider: HIV, infectious mononucleosis, or Lyme disease.
        • Lyme disease is the leading cause of pediatric facial nerve paralysis in Lyme endemic areas.2
  •  Evaluation:1-3
    • Perform a thorough history and physical examination. Question specifically regarding the time course of the illness, recent trauma, and signs and symptoms of infection. Examine the dermis and document a complete neurologic examination.
      • Time course: patients with neoplasms compressing the facial nerve often report prolonged, progressively worsening symptoms. Recurrent facial paralysis, extreme pain, prolonged symptoms, or additional CN abnormalities => suspect a mass lesion.
      • Trauma: facial nerve = most commonly injured cranial nerve. Temporal bone fractures with facial nerve transection frequently present with ipsilateral facial paralysis.1
      • Infections of the middle ear, mastoid, or external auditory canal may result in ipsilateral facial paralysis.
      • Examine the dermis: Herpes Zoster oticus may initially present as an isolated facial paralysis. Examine the ipsilateral ear, oral cavity, face, neck, and shoulder for vesicular eruptions. In comparison to patients with Bell’s palsy, individuals suffering from Herpes Zoster oticus frequently experience pain out of proportion to physical exam findings.3
  •  Treatment:1
    • Current evidence supports the use of corticosteroids for the treatment of Bell’s palsy; the use of antivirals is controversial, though current data suggest benefit. Patients without contraindications to systemic corticosteroid therapy should receive prednisone (1mg/kg) for 7-10 days with or without a short taper.1
      • The largest randomized, double-blinded, placebo-controlled trial (n=496) assessing prednisolone or acyclovir vs. placebo demonstrated complete recovery of facial nerve function at 3 months post diagnosis in 64% of patients with placebo and 83% of those who had been prescribed prednisolone 25mg PO BID for 10 days (p <0.001).4
      • In terms of acyclovir, data analysis revealed complete recovery of facial nerve function in 72% of patients who received acyclovir alone vs. 75.7% of those who received placebo.4
    • Artificial tears or lubricating ointment should be applied if limited lid closing. Advise eye-taping QHS while symptomatic.
  • Pearl:
    • Hemifacial paresis results from lower motor neuron pathology.  Documentation of the neurologic examination should specifically note forehead involvement. Absence of forehead involvement on examination => stroke until proven otherwise.1


  1. Stettler B. Brain and Cranial Nerve Disorders. In Rosen’s Emergency Medicine. 8th Ed. Philadelphia, Saunders Elsevier. 2014; 1409-1418.e2.
  2. Cook S, et al. Lyme disease and seventh nerve paralysis in children. Am J Otolaryngol 1997; 18: 320.
  3. Jackson C, Doersten P. The facial nerve: current trends in diagnosis, treatment, and rehabilitation. Med Clin North Am. 199; 83:179.
  4. Sullivan F, Swan I, Donnan P, Morrison J, Smith B, et al. Early treatment with prednisolone or acyclovir in Bell’s palsy. N Engl J Med. 2007; 357(16): 1598-607.


For Additional Reading:

Bell’s Palsy: Pearls and Pitfalls in evaluation and Management:


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