What is the initial workup for a patient presenting with symptoms suggestive of Bell's palsy?

Initial Workup for Bell's Palsy

The initial workup for a patient presenting with symptoms suggestive of Bell's palsy should focus on a thorough neurological examination to confirm the diagnosis, with targeted diagnostic testing based on clinical suspicion rather than routine laboratory or imaging studies. 1

Diagnostic Approach

Clinical Evaluation

• Look for key diagnostic features:
  • Acute onset of unilateral facial weakness or paralysis (typically developing over 1-3 days) 2, 3
  • Involvement of the forehead (crucial distinguishing feature from central causes) 3
  • Absence of other neurologic abnormalities 3
  • Possible associated symptoms:
    • Postauricular pain
    • Dysgeusia (altered taste)
    • Hyperacusis
    • Dry eye or excessive tearing 4

Laboratory Testing

• Laboratory tests are not routinely required for diagnosis of typical Bell's palsy 3
• Targeted testing should be ordered based on clinical suspicion:
  • Random glucose or HbA1c (Bell's palsy is more common in patients with diabetes) 1, 2
  • Lyme disease testing (in endemic areas or with suggestive history) 2
  • Consider CBC, electrolytes, and renal function if clinically indicated 1

Imaging

• Neuroimaging should not be performed routinely 1
• Reserve imaging for atypical presentations such as:
  • Focal neurological deficits beyond isolated facial weakness
  • Sudden onset with concern for TIA/stroke
  • Progressive symptoms
  • Associated headache or altered mental status
  • History of malignancy or immunocompromised state 1

Differential Diagnosis Considerations

• Bell's palsy is a diagnosis of exclusion 5
• Rule out other causes of facial weakness:
  • Stroke (typically spares forehead due to bilateral upper motor neuron innervation)
  • Ramsay Hunt syndrome (herpes zoster oticus with vesicles in ear canal)
  • Lyme disease (in endemic areas)
  • Tumors affecting the facial nerve
  • Trauma
  • Sarcoidosis

Initial Management Considerations

• Oral corticosteroids are strongly recommended for adult Bell's palsy if diagnosed within 72 hours of symptom onset 1, 3

  • Prednisone 50-60 mg daily for 5 days followed by a 5-day taper 3

• Antiviral therapy may be considered in combination with steroids 1, 3

  • Valacyclovir (1 g three times daily for 7 days) or
  • Acyclovir (400 mg five times daily for 10 days) 3

• Eye protection is crucial for patients with impaired eye closure:

  • Artificial tears during the day
  • Lubricating ointment at night
  • Taping eyelids closed if necessary 1

Common Pitfalls to Avoid

1. Failing to examine forehead involvement (central lesions typically spare the forehead)
2. Ordering unnecessary imaging for typical presentations
3. Delaying corticosteroid treatment beyond 72 hours of symptom onset
4. Neglecting eye protection measures in patients with incomplete eye closure
5. Using antivirals alone without steroids (not recommended) 3