Bell's Palsy

Question 1

What is Bell’s palsy?

Answer 1

An acute neurological condition presenting with rapid onset of UNILATERAL facial paralysis.

Question 2

What infection can Bell’s palsy be linked to?

Answer 2

HSV

Question 3

Give some risk factors for Bell’s palsy

Answer 3

• Pregnancy
• Severe pre-eclampsia
• Hypertension
• Obesity
• Diabetes mellitus
• URTIs

Question 4

Which cranial nerve is the facial nerve?

Answer 4

CN VII

Question 5

What are the 5 branches of the facial nerve it divides into?

Answer 5

1) Temporal
2) Zygomatic
3) Buccal
4) Marginal mandibular
5) Cervical

Question 6

What are the 3 main functions of the facial nerve ?

Answer 6

1) Motor fibres –> muscles of facial expression

2) Sensory fibres

3) Autonomic nerve fibres

Question 7

What is the sensory function of the facial nerve?

Answer 7

Sensory function for taste from the anterior 2/3 of the tongue.

Question 8

What is the autonomic function of the facial nerve?

Answer 8

Parasympathetic fibres to:

• lacrimal gland (stimulating tear production)
• salivary glands (submandibular and sublingual)

Question 9

Features of Bell’s nerve palsy?

Answer 9

Unilateral facial paralysis:

1) Acute (<72h)

2) Involves the forehead AND lower parts of the face on the affected side

3) Pain in the ear and surrounding area

4) Loss of taste in the anterior tongue in 35% of patients

5) Hyperacusis (increased sensitivity to noise) is a rarer symptom

Question 10

Is Bell’s palsy an UMN or LMN facial nerve palsy?

Answer 10

LMN

Question 11

What are some upper facial signs seen in Bell’s palsy?

Answer 11

• inability to wrinkle forehead
• inability to close eye fully on the affected side

Question 12

What are some lower facial signs seen in Bell’s palsy?

Answer 12

• loss of the nasolabial labial fold
• drooping of the mouth (more pronounced when the patient tries to smile)

Question 13

How can the severity of paralysis in Bell’s palsy be graded?

Answer 13

House-Brackmann facial paralysis scale, which is graded from 1 (normal) to 6 (complete paralysis).

Question 14

What is it important to distinguish Bell’s palsy from?

Answer 14

An UMN facial nerve palsy –> immediate management as a possible stroke

Question 15

How to differentiate between UMN and LMN facial nerve palsy?

Answer 15

The forehead will be spared in an UMN lesion so the patient can move their forehead on the affected side.

In a LMN, the forehead is not spared.

This is because each side of the forehead has UMN innervation by both sides of the brain. However, each side of the forehead only has LMN innervation from one side of the brain.

Question 16

Diagnosis of Bell’s palsy?

Answer 16

Diagnosis of exclusion

Question 17

Mx of Bell’s palsy?

Answer 17

1) Prednisolone (if <72h of symptom onset)

2) Good eye care on affected side due to inability to completely close the eyelid e.g. artificial tears or ocular lubricant, using tape to close the eye overnight

3) Supporting nutrition by using straws and a soft diet

Question 18

Prognosis of Bell’s palsy?

Answer 18

Good prognosis, recovery often within 3 weeks.

If not, refer to 2ary care.