Facial paralysis

Question 1

Prevalence of idiopathic facial paralysis

Answer 1

• very common

Question 2

CS of dogs with unilateral facial paralysis

Answer 2

• facial asymmetry (drooping on affected side)
• saliva staining of neck from drooling out of corner of mouth
• absence of blink (including absent menace and palpebral response)
• lateral deviation of the nose when viewed from above

Question 3

Investigation

Answer 3

• need to do thorough neuro exam including other CN to determine if isolated peripheral facial nerve paralysis or central (indicated when other neuro deficits other than facial nerve involved, esp proprioceptive deficits)
  – if central then it is not idiopathic facial paralysis but needs consideration for other brain pathologies
• important to do Schirmer tear test to investigate for dry eye
• idiopathic facial paralysis is negative on all diagnostic tests except for MRI where contrast enhancement of the facial nerve in the temporal bone can be demonstrated in many cases

Question 4

topical consdierations

Answer 4

• the facial nerve enters the skull in the internal acoustic meatus alongside the vestibulocochlear nerve -> idiopathic facial nerve and vestibular syndrome often seen concurrently
• parasympathetic outlaw to the lacrimal glands branches off from the facial canal in the temporal bone -> facial paralysis without dry-eye is almost always peripheral

Question 5

Treatment

Answer 5

• no specific tx -> conservative tx recommended
• dry-eye should be tx with lubrication as needed
• prognosis for full return of function is guarded

Question 6

What can chronic facial paralysis without return of function result in?

Answer 6

• contracture of the facial muscles
• O’s may report that they suspect animals to have subsequently developed contralateral facial paralysis