ENT: Facial palsy

Question 1

what is Facial nerve palsy?

Answer 1

isolated dysfunction of the facial nerve

Question 2

how does Facial nerve palsy present?

Answer 2

unilateral facial weakness

Question 3

where does the facial nerve emerge from and which structures does it pass through?

Answer 3

brainstem at the cerebellopontine angle

it passes through the temporal bone and parotid gland.

Question 4

the facial nerve divides into which 5 branches?

Answer 4

Temporal
Zygomatic
Buccal
Marginal mandibular
Cervical

Question 5

what is the function of the facial nerve?

Answer 5

Motor: Supplies the muscles of facial expression, the stapedius in the inner ear and the posterior digastric, stylohyoid and platysma muscles in the neck.

Sensory: carries taste from the anterior 2/3 of the tongue.

Parasympathetic: it provides the parasympathetic supply to the submandibular and sublingual salivary glands and the lacrimal gland (stimulating tear production).

Question 6

with reference to Facial nerve palsy, how would an upper motor neurone lesion present?

Answer 6

the forehead will be spared and the patient can move their forehead on the affected side.

Question 7

with reference to Facial nerve palsy, how would a lower motor neurone lesion present?

Answer 7

the forehead will NOT be spared and the patient cannot move their forehead on the affected side.

Question 8

which cranial nerve is the facial nerve?

Answer 8

CNVII (7)

Question 9

what are the three types of nerve injury?

Answer 9

Neuropraxia
Axonotmesis
Neurotmesis

Question 10

what is Neuropraxia?

Answer 10

nerve injury:

• mildest form
• due to pressure on the nerve (being squashed)
• conduction block of function without nerve degeneration
• reversible if pressure taken away

Question 11

what is Axonotmesis?

Answer 11

nerve injury:

• more severe Neuropraxia
• The axons and their myelin sheath are damaged
• due to pressure on the nerve (being squashed)

Question 12

what is Neurotmesis?

Answer 12

nerve injury:

• total nerve transection

Question 13

what investigations would you do to diagnose Facial nerve palsy?

Answer 13

Audiometry
Stapedius reflexes
MRI / CT
ENG/EMG (neurophysiology)

Question 14

how do you manage Bell’s Palsy?

Answer 14

If patients present within 72 hours of developing symptoms - prednisolone

• lubricating eye drops

Question 15

what is Bell’s palsy?

Answer 15

Bell’s palsy is an acute unilateral peripheral facial nerve palsy in patients for whom physical examination and history are otherwise unremarkable, consisting of deficits affecting all facial zones equally that fully evolve within 72 hours.

NB: facial palsy that is progressive, waxing and waning, or affects facial zones in an uneven fashion, is not Bell’s palsy.

• single episode
• unilateral
• absence of other symptoms

Question 16

the herpes zoster virus can cause which time of facial nerve palsy?

Answer 16

Ramsay-Hunt Syndrome

Question 17

which virus causes Ramsay-Hunt Syndrome?

Answer 17

herpes zoster virus

Question 18

how does Ramsay-Hunt Syndrome present?

Answer 18

• unilateral lower motor neurone facial nerve palsy

- painful/tender vesicular rash in ear canal

Question 19

how do you manageRamsay-Hunt Syndrome?

Answer 19

Treatment should ideally be initiated within 72 hours. Treatment is with:

Prednisolone
Aciclovir

Patients also require lubricating eye drops.

Question 20

what is Myasthenia gravis?

Answer 20

autoimmune condition that causes muscle weakness that gets progressively worse with activity and improves with rest

Circulating antibodies against the nicotinic acetylcholine receptor (AChR) and associated proteins impair neuromuscular transmission.

Question 21

what type of people does Myasthenia gravis typically affect?

Answer 21

Interestingly myasthenia gravis affects men and women at different ages. Typical patients are either a woman under the age of 40 or a man over the age of 60.

• people tumours of thymus gland

Question 22

when are the symptoms of Myasthenia gravis typically worse?

Answer 22

Symptoms are typically minimal in the morning and worst at the end of the day.

Question 23

how might Myasthenia gravis present?

Answer 23

The symptoms most affect the proximal muscles and small muscles of the head and neck. It leads to:

• Extraocular muscle weakness causing double vision (diplopia)
• Eyelid weakness causing drooping of the eyelids (ptosis)
• Weakness in facial movements
• Difficulty with swallowing
• Fatigue in the jaw when chewing
• Slurred speech
• Progressive weakness with repetitive movements

Question 24

what investigations would you do to diagnose Myasthenia gravis?

Answer 24

Diagnosis can be made testing directly for the relevant antibodies:

Acetylcholine receptor (ACh-R) antibodies (85% of patients)

Muscle-specific kinase (MuSK) antibodies (10% of patients)

LRP4 (low-density lipoprotein receptor-related protein 4) antibodies (less than 5%)

A CT or MRI of the thymus gland is used to look for a thymoma.

Question 25

what are the treatment options for Myasthenia gravis?

Answer 25

1. Reversible acetylcholinesterase inhibitors (usually pyridostigmine or neostigmine) increases the amount of acetylcholine in the neuromuscular junction.
2. immunosuppression (e.g. prednisolone or azathioprine).
3. thymectomy.

Question 26

what is Myasthenic Crisis?

Answer 26

Myasthenic crisis is a severe complication of myasthenia gravis. It can be life threatening. It causes an acute worsening of symptoms, often triggered by another illness such as a respiratory tract infection.