Neuro-opthalmology

Question 1

List the important causes of optic disc swelling?

Answer 1

Malignant hypertension
Papilloedema
Optic neuritic
Non arteretic ant. ischaemiac optic neuropathy (AION)
AION (temporal arteritis)

My pet ostrich never ages

Question 2

Describe the symptoms and important points regarding optic neuritis?

Answer 2

Symptoms:
Retrobulbar pain worse on movement.
Globe tenderness.
Central scotoma (black spot in the centre of their vision)

Signs on examination:
Optic disc is not always swollen.
Will have red desaturation (see's red colour as less bright more pink)
RAPD
May have other neuro signs

Note: Associated with risk of developing MS

Question 3

Describe the symptoms and important points regarding papilloedema?

Answer 3

Symptoms: (must be bilateral)
Transiently obscured vision

Signs on examination:
Gradually progressive field loss
Splinter haemorrhages.
On fundoscopy:
-exudates
-cotton wool spots
-retinal folds near the disc

Question 4

Describe the symptoms and important points regarding of AION (temporal arteritis)?

Answer 4

Severe temporal headache.
Scalp tenderness.
Jaw claudication

Visual loss caused by inflammatory infarction of the posterior ciliary aa.

Investogations:
Raised ESR and C reactive protein
Treat with steroids ~2years

Question 5

Describe the symptoms and important points regarding of non AION?

Answer 5

Infarction of the post. ciliary aa.
50% of patients are hypertensive.
ESR will not be rasied and there are no systemic symptoms.

Question 6

Which muscles control the iris and which nervous systems are they each controlled by?

Answer 6

Dilator pupillae:- sympathetic

Constrictor pupillae:- parasympathetic

Question 7

What are the 3 physiological influences on the pupil?

Answer 7

Light.
Strong emotion (fight or flight causes pupil dilation)
Accommodation.

Question 8

Outline the 3 things which occur in the accommodation reflex?

Answer 8

Pupils constrict.
Eyes converge (contraction of medial rectus)
Ciliary muscles contract, relaxing the zonules and thickening the lens increasing the refractive power of the lens.

Question 9

Outline the pupillary light reflex pathway.

Answer 9

Afferent:
Light–> optic nn —> chiasm —> tract —> pre tectal nuclei

At this point 2 (one for each eye) edinger westphal nuclei are recruited. Reason for consensual response.

Efferent:
Signal travels along pathway of CNIII —> ciliary ganglion
—> constrictor pupillae

Question 10

Outline the pupillary sympathetic pathway.

Answer 10

For example: fearful stimulus

Hypothalamus —> 1st order neuron synapse in spinal cord

2nd order neuron —> synpases in superior cervical ganglion

fibres travel around the external carotid and split up into seperate fibres supplying:

• sweat glands to the forehead and to supply the levator palpebrae superioiris (elevated eyelid)
• dilator pupillae
• sweat glands in the face

When thinking what it supplys think HORNERS

Question 11

Define the term anisocorea?

Answer 11

Unequal pupil size >1mm

Question 12

What are the potential causes of anisocorea?

Answer 12

Horner’s syndrome
CN III palsy
Adie’s pupil
Traumatic mydriasis

Question 13

Describe the clinical features of Horner’s syndrome?

Answer 13

Sympathetic chain damage pressure causing:

• Partial ptosis (levator palpebrae superioiris)
• Meiosis (unopposed action of constrictor pupillae as no sympathetic input)
• Anhydriasis.
• Apparent enopthalamus (sunken eyelid)

Question 14

What are the potential causes of Horner’s syndrome? Think about the different order neurons.

Answer 14

1st order neuron causes:

• CNS disease (SOL, infection, CVA, demyelination)
• Cervical region compression (tumor) or injuries

2nd order neuron causes:
Sympathetic chain compression from:
-Cervical rib
-Pancos tumour
-Aneurysms 
-Lypathendopathy

Apical TB
Neck trauma (surgery)

3rd order neuron causes:

• ICA aneurysm (suspect if also complaining of neck pain)
• Migraines and cluster headaches
• Idiopathic

Question 15

Describe the presentation of CNIII palsy?

Answer 15

Full ptosis
Eye will be pointing down and out due to the unopposed actions of the lateral rectus and superior oblique
Efferent pupil defect (anisocorea) as nn fibres which control constrictor pupillae travel with CNIII. Mydriasis.

Question 16

What are the causes of CNIII palsy?

Answer 16

Vascular III nn palsy:
Diabetes/hypertension pupil usually spared. Self limiting.

Brainstem injury:
Tumour, CVA, demyelination.

Cavernous sinus:
Carotid cavernous fistula
Tumour
Inflammation

Skull Pain:
Post communicating aa aneurysm
Extradural haematoma

Orbit:
Trauma, Inflammation, Tumour.

Infiltrative lymphomas.

Question 17

Describe the clinical features of Adie’s pupil?

Answer 17

Light reflex is absent.
Accommodation pupil reflex is normal/slow.

AKA enlarged dilated pupil.
May be associated with reduced tendon reflexes (Holmes ad syndrome)

Usually affect young women, idiopathic cause but thought to be post infective.

Question 18

Describe the symptoms of traumatic mydriasis?

Answer 18

Mydriasis
Photophobia
Eye ache
Watering

Usually caused by blunt trauma damaging the the iris sphincter muscle. Usually reversible.

Question 19

In a pupil examination what should you do if you find anisocrea?

Answer 19

Turn off the light.

Question 20

What are the differentials for an abnormal small/large pupil?

Answer 20

Small pupil:
Horner’s syndrome
Pharmacological
Previous synechia (post. surface of the iris is adhered to the lens.

Large pupil:
Adie’s pupil
CN III palsy
Traumatic mydriasis

Question 21

Which medications can affect pupil size?

Answer 21

Dilate:
TCA's
Phenylephirine chloride
Cocaine
Amphetamines

Constricts: Opiods