Clinic: Pupils summarised

Question 1

Afferent innervation of pupils (5)

Answer 1

Retina –> ON –> OC –> OT (bilaterally) –> pretectal nuclei (bilateral)

Question 2

Efferent innervation of pupils (4)

Answer 2

EW nucleus –> 3rd nerve –> Cil ganglion –> Short cil nerves

Question 3

Sympathetic innervation of dilator pathway (5)

Answer 3

Hypothalamus –> ciliospinal centre (@T1) –> superior cervical ganglion –> dilator pupillae + eyelid smooth muscle

Question 4

Parasympathetic innervation of sphincter pathway (4)

Answer 4

EW nucleus –> 3rd nerve –> cil ganglion –> short cil nerve –> iris sphincter

Question 5

Diagnostic criteria for Horner’s syndrome (8)

Answer 5

Anisocoria (in dim) with dilation lag
Plus any of: ptosis, facial anhydrosis, mildly reduced IOP (1-2) on affected side, conj flush, increased accommodation, iris heterachromia (if congenital/long standing)

Question 6

How can we localise the pathology of horner’s syndrome?

Answer 6

1. Apraclonidine: reversal of anisocoria indicates horner’s syndrome (alternatively, no dilation with cocaine will also reveal horner’s syndrome)
2. Phenyl Ephrine 1%:
   dilation = post-ganglionic horners (3rd order neuron)
   no dilation = pre-ganglionic or central horners

http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0256-95742010001100020

Question 7

List 3 causes for 1st order neuron horner’s

Answer 7

stroke
tumour
neck trauma

Question 8

List 4 causes for 2nd order neuron horner’s

Answer 8

lung cancer (pancoast tumour)
Surgery in chest cavity
neck trauma
thyroid mass

Question 9

List 4 causes for 3rd order neuron horner’s

Answer 9

damage to carotid artery
damage to jugular vein
tumours
infection

Question 10

List 2 causes for congenital horner’s

Answer 10

brachial plexus trauma
forceps delivery at birth

Question 11

Describe the light/near response for a parasympathetic mid brain lesion

Answer 11

Light: no response
Near: yes response (constriction)

Question 12

List 2 midbrain lesions resulting in parasympathetic deficits

Answer 12

Parinauds syndrome (large pupil)
Argyll Robertson pupil (small pupil)

Question 13

Describe the clinical features of parinauds syndrome (2)

Answer 13

Large pupil
Nystagmus on attempted up gaze

Question 14

List one potential cause of parinauds syndrome

Answer 14

pineal tumour

Question 15

Describe the clinical features of Argyll Robertson Pupil (3)

Answer 15

Both pupils irregular and miotic (ironically, since its a parasymp problem)
total absence of light reaction (both pupils)
Brisk near response

Question 16

List 2 potential causes of Argyll Robertson pupil

Answer 16

Neurosyphilis (main one to suspect)
Diabetic neuropathy

Question 17

Describe the light/near response for a parasympathetic peripheral brain lesion

Answer 17

Light: no
Near: no

Question 18

List 4 potential causes of a peripheral brain lesion

Answer 18

Iris trauma (will also have increased IOP)
CN3 palsy
Drug usage
Viral (Adies, HSV)

NB: Adies is most common cause

Question 19

List 2 clinical features of Adies tonic pupil (3)

Answer 19

Mydriasis (in bright)
Cholinergic supersensitivity (0.125% or 1% pilocarpine can identify)
Sector iris palsy

Question 20

List 4 potential causes of CN3 palsy

Answer 20

head injury
infection
migraine
brain tumour

Question 21

Why should you check ocular motility in a pupil patient?

Answer 21

Check for CN3 palsy.

Question 22

Describe the clinical features of complete CN3 palsy (3)

Answer 22

Complete ptosis
Eyes down + out
Pupil may be fixed + dilated or may be normal

Question 23

Describe the clinical features of partial CN3 palsy (3)

Answer 23

STRAB - ExoT (weak MR) or HyperT (weak IR) or HypoT (weak SR and/or IIO)
Ptosis
Enlarged pupil - poor light and near response (due to weak sphincter)

Question 24

How do you manage a CN3 palsy? (3)

Answer 24

Immediate referral: urgent MRI + MRA or CT
Extreme emergency if pain + stiffness + headache (possible aneurysm rupture)

Question 25

List 6 potential causes for RAPD

Answer 25

Large RD CRAO/CRVO On ischemia Asymmetric Glaucoma Optic Neuritis Optic Nerve compression

Question 26

How do you grade RAPD?

Answer 26

No RAPD: pupils constrict and show equal physiological escape 1+: escape apparent @ 3 sec only 2+: escape apparent @ 2 sec 3+: escape apparent @ 1 sec 4+: immediate dilation (no constriction)

Question 27

How can you differentially diagnose CN3 palsy from pharmacological pupil dilation?

Answer 27

Pilocarpine 1% test. If constriction occurs, it's CN3 palsy.