Pupil disorders

Question 1

what anatomy causes pupil constriction

Answer 1

circular muscles in the iris that cause pupil constriction

Question 2

what stimulates pupillary constriction

Answer 2

stimulated by parasympathetic nervous system using AcH as a neurotransmitter

Question 3

where do the Parasympathetic fibres that innervate pupil constriction arise from

Answer 3

travel along the oculomotor nerve (CN3)

Question 4

what anatomy causes pupil dilation

Answer 4

dilatory muscles
-travel straigth from the inside to outside of the iris

Question 5

how is pupillary dilation stimulated

Answer 5

by sympathetic nervous system using adrenaline as a neurotransmitter

Question 6

what can cause an abnormal pupil shape 6

Answer 6

trauma to sphincter muscles in the iris
-cataract surgery or other eye operations

anterior uveitis- can cause adhesions that make pupils mishapen

acute angle closure glaucoma -can cause ischaemic damage to muscles of iris
-usually vertical oval

rubeosis iridis (neovascularization in the iris) can cause distorted shape of iris and pupils
-assoc w diabetic retinopathy

coloboma
-congential
-hole in iris makes irregular pupil shape

tadpole pupils
-spasm in a segment of iris causing misshapen pupil
-temporary and assoc w migrains

Question 7

causes of mydriasis (dilated pupil) 7

Answer 7

Third nerve palsy

Holmes-Adie syndrome

Raised intracranial pressure

Congenital

Trauma

Stimulants such as cocaine

Anticholinergics

Question 8

causes of miosis (constricted pupil) 6

Answer 8

Horners syndrome

Cluster headaches

Argyll-Robertson pupil (in neurosyphilis)

Opiates

Nicotine

Pilocarpine

Question 9

what does a third nerve palsy cause 3

Answer 9

ptosis (drooping of upper eyelid)

dilated non-reactive pupil

divergent strabismus (squint) in affected eye
-‘down and out’ position of eye

Question 10

causes of third nerve palsy when all three syx shown (called surgical third) 6

Answer 10

this is caused by compression of teh nerve including the parasympathetic fibres

could be:
can be idiopathic

cavernous sinus thrombosis

posterori communicating artery aneurysm

tumour

trauma

raised ICP

Question 11

causes of third nerve palsy WITH sparing of the pupil 2

Answer 11

microvascular cause as parasympathetic fibres are spared
could be:
-DM
-HT
-ischaemia

Question 12

syx of horners syndrome 3

Answer 12

anhidrosis

ptosis

miosis

(can also get enopthalmos (sunken eye)

Question 13

basic pathophys of horners

Answer 13

damage to sympathetic nervous system supplying the face

Question 14

describe the journery of teh sympathetic nerves to the head relevant to horners syndreom

Answer 14

sympathetic nerves arise from the spinal cord in the chest (called pre-ganglionic fibres)

then enter sympathetic ganglion at base of neck and exit as post-ganglionic nerves

post-ganglionic nerves then travel to the head, running alongside the internal carotid artery

Question 15

how can the location of the pathology causing horners syndromes be determined

Answer 15

by where the anhidrosis is

central lesions(spinal cord)- anhidrosis of arms+trunk+face

pre-ganglionic lesions- just face

post ganglionic- do not cause anhidrosis

Question 16

central lesion causes of horners syndrome 4

Answer 16

4 ‘S’

Stroke
multiple Sclerosis
Swelling (tumours)
Syringomyelia (cyst in spinal cord)

Question 17

pre-ganglionic causes of horner syndrome 4

Answer 17

4 ‘T’

Tumour (pancoast tumour)
Trauma
Thyroidectomy
Top rib (cervical rib growing above the first ribe above the clavicle)

Question 18

post-ganglionic causes of horner syndrome 4

Answer 18

4 ‘C’

Carotid aneurysm
Carotid artery dissection
Cavernous sinus thrombosis
Cluster headache

Question 19

testing for horners

Answer 19

cocaine eye drops (google to see if available online)

Question 20

define a holmes adie pupil

Answer 20

unilateral dilated pupil
-sluggish to react to light with slow dilation of pupil following constriction

causes by damage to post-ganglionic parasympathetic fibres

Question 21

define Argyll-robertson pupil

Answer 21

specific finding in neurosyphilis

contricted pupil that accommodates whe focusing on near object but does not react to light

often irregularly shaped

commonly called prosistutes pupil due to relation to neurosyphilis and because ‘it accommodates but does not react’