9A. Peripheral facial palsy (Bell-paresis)

Page created on June 3, 2021. Not updated since.


Peripheral facial palsy is a peripheral lesion of the facial nerve. In the cases where this lesion is idiopathic, the condition is called Bell’s palsy.


  • Idiopathic (= Bell’s palsy)
  • Trauma (involving pyramidal bone)
  • Lyme disease
  • Parotid tumour
  • Brainstem stroke (involving facial nucleus)

Bell’s palsy is caused by idiopathic inflammation of CN VII in the facial canal. It might be due to viral infection.

Clinical features

Symptoms of peripheral facial palsy are ipsilateral to the lesion and include:

  • Motor symptoms
    • Frowning, eye-closing, blinking is impaired
    • Inability to close the eye
    • Drooping corner of mouth
    • Disappearance of nasolabial fold
  • Pain in ear
  • Hyperacusis
  • Abnormal lacrimation
  • Abnormal taste

If Lyme disease is the cause, the facial palsy may be bilateral.

Diagnosis and evaluation

If peripheral facial palsy is the only symptom, Bell’s palsy is assumed, and no investigation is needed. If other symptoms are present, investigate with MRi, LP, etc.


In most cases Bell’s palsy resolves completely in a few weeks without treatment. Steroids hasten the resolution if given within the first days of symptoms. Acyclovir can be used if viral etiology is suspected.

To prevent atrophy the patient should do physiotherapy of the face and artificial eye drops to prevent dry eyes.

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9B. Thrombosis of the intracranial sinuses

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Neurology 2

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