A 42-year-old man attends the emergency department complaining of weakness down one side of his face. Over the last 2 days, he has noticed an altered taste sensation and pain in and around the ear on the same side. There is no history of trauma. He has not noticed any discharge from the ear and there is no limb weakness. He is a known asthmatic and he suffers with depression. He has recently given up smoking and has spent several weeks in India on holiday with his wife. He is currently using salbutamol and becotide inhalers and takes paroxetine 20 mg od. He has no known allergies.
Cardiovascular, respiratory and abdominal examinations are normal. His gait and balance are normal. Neurology of the upper and lower limbs is unremarkable. Examining the face you notice some asymmetry, which is more obvious when you ask the patient to smile.
When you ask him to show his teeth, the right side of the face droops. On raising his eyebrows, there is a loss of the forehead facial wrinkles on the right and he has difficulty in closing his right eye. The rest of the cranial nerves appear intact and examination of the ear is normal. There is no evidence of trauma and the salivary glands feel normal.
• Which nerve has been affected?
• Does this represent an upper or lower motor neurone lesion?
• What is the differential diagnosis?
• What is the treatment in this case?
The patient has a lower motor neurone right-sided facial nerve palsy. The unilateral paresis of the facial muscles makes it difficult for the patient to close the eye on that side and the mouth droops on smiling. The forehead wrinkles are also lost when the patient raises the eyebrows and there is loss of the nasolabial fold.
The facial paresis would have spared the upper facial muscles if the patient had an upper motor neurone lesion (UMN), i.e. a lesion proximal to the facial nucleus located in the pons. The upper facial muscles receive a bilateral cortical innervation, so their function is maintained by the intact contralateral nerve supply in an UMN lesion.
Differential diagnoses !
• Upper motor neurone lesion:
• cerebrovascular accident
• cerebral tumour
• multiple sclerosis
• motor neurone disease
• Lower motor neurone lesion:
• idiopathic, i.e. Bell’s palsy
• Ramsay Hunt syndrome, i.e. Herpes zoster infection of the facial nerve
• acute otitis media
• trauma, e.g. fracture of the temporal bone, surgery
• parotid mass, e.g. carcinoma
• cerebello-pontine angle tumour, e.g. acoustic neuroma
Bell’s palsy is diagnosed when other lower motor neurone pathologies have been excluded. It is the most likely diagnosis in this case. The aetiology is thought to be viral and secondary to inflammation within the facial nerve.
Initial treatment is:
• steroids, e.g. prednisolone within 48 h of symptoms
• consider antiviral therapy, e.g. aciclovir
• eye protection as the patient will not be able to blink.
• The forehead is spared in upper motor neurone lesions.