Cranial Nerve Lesions

Question 1

Describe the Anatomical basis of Bell’s Palsy

Answer 1

Affects facial nerve. 
Can be caused by a virus possibly herpes
Brain Tumor
Lyme disease
Meningitis
Stroke mimic symptoms

Compresses the nerve from inflammation around it’s exit point at the stylomastoid foramen as it exits the skull, disrupting nerve signal transmission.

Question 2

Clinical effects of Bell’s Palsy

Answer 2

Anterior taste of 2/3rd of tongue can be impaired On one side.. (chorda tympani innervates the tongue, a branch of the facial nerve)

Drooping eyelids, facial muscles. Cannot wrinkle forehead. Is Unilateral, in very rare cases it is Bi lateral,
Pain near ear, change in taste twitching ,weakness or total loss on one side are some symptoms.

May also have tingling and numbness, or pain.

Question 3

Prognosis of Bell’s? Complications?

Answer 3

Most start to regain control lover muscles with around 3 weeks. 75% of patients recover completely.
There are complications of sequele in patients take much longer to recover. Such as chronic loss of taste, facial spasm and eye damage.
Treatment can include steroids and antivirals.

Corneal infections are a risk as some patients cannot close affected ye to due eye muscles.

Question 4

What are the common signs and symptoms of Horner’s syndrome?

Answer 4

Symptoms of horners are usually unilateral and include, lack of facial sweating (anhidrosis),

drooping eyelids (ptosis)

constricted pupil (miosos)

eyeball sinking (enopthalmos)

Also upside down ptosis (elevation of lower eyelid)

Pupillary dilation lag.

Loss of cilliospinal reflex (dilation of ipsilateral pupil in response to pain)

Blood shot eyes (bloodshot conjuctiva)

Sometimes unilateral hair straightening

In congenital cases- heterochromia iridum, Which is a difference in colours of the eye (iris) or skin. Due to lack of of sympathetic simulation interfering with melanin pigmentation.
Sometimes there is flushing on the affected side due to dilation of blood vessels. If there is a preganglionic lesion)
Headache if postganglionic lesion

Question 5

What are the common causes of Horner’s syndrome and why do they cause the condition to develop

Answer 5

Usually aquired as the result of diseases, can be congenital. Either inborn or iatrogenic.

May reflect serious disease in neck or chest – pancoast tumour of lung. ( or infection)

Lesion of the primary neuron
Brainstem stroke or tumor, 33% of patients with brainstem lesions demonstrated in one study.

Carotid Artery ischemia

Middle cranial Fossa neoplasm

These causes cause a lesion to the sympathetic outflow of nerves on affected (ipsilateral) side. Fibers traveling from the hypothalamus to the face and eyes through the brainstem . It can affect first, third and third order nerve fibers.

Question 6

Give examples of 1st, 2nd and 3rd order disorders

Answer 6

First order synapse with pre-ganglionic sympathetic nerves – can be caused by MS,basal meningitis, neck trauma. Spinal cord tumours.

Second order synapse in the superior cervical ganglion, can be caused by pancoast tumour, lower brachial plexus trauma , neuroblastoma
Mandibular dental abscess.
leukaemia,

Third order (post ganglionic)  send branches to blood vessels and sweat glands of face then enter the eye. Could be caused by headaches, herpes zoster or raeders syndrome.