Abnormal pupils

Question 1

Abnormal pupils

Answer 1

Examine this patient’s eyes.

1. Horner’s pupil
2. Holmes–Adie (myotonic) pupil
3. Argyll Robertson pupil
4. Oculomotor (III) nerve palsy

Question 2

Clinical signs of Horner’s pupil

Answer 2

‘PEAS’
1. Ptosis (levator palpebrae is partially supplied by sympathetic fibres)
2. Enophthalmos (sunken eye)
3. Anhydrosis (sympathetic fibres control sweating)
4. Small pupil (miosis)
5. May also have flushed/warm skin ipsilaterally to the Horner’s pupil due to loss of vasomotor sympathetic tone to the face.
Extra points
* Look at the ipsilateral side of the neck for
1. Scars (trauma, e.g. central lines, carotid endarterectomy surgery or aneurysms) and
2. Tumours (Pancoast’s).

Question 3

Cause of Horner’s according to the sympathetic tract’s anatomical course

Answer 3

1. Brain stem: MS; Stroke (Wallenberg’s)
2. Spinal cord: Syrinx
3. Neck: Aneurysm; Trauma; Pancoast’s

Question 4

Clinical signs of Holmes–Adie (myotonic) pupil

Answer 4

Moderately dilated pupil that has a poor response to light and a sluggish response to accommodation (you may have to wait!)

Extra points
- Absent or diminished ankle and knee jerks

Question 5

Discussion of Holmes–Adie (myotonic) pupil

Answer 5

A benign condition that is more common in females. Reassure the patient that nothing is wrong.

Question 6

Clinical signs of Argyll Robertson pupil

Answer 6

1. Small irregular pupil
2. Accommodates but doesn’t react to light
3. Atrophied and depigmented iris

Extra points
* Offer to look for sensory ataxia (tabes dorsalis)

Question 7

Discussion of Argyll Robertson pupil

Answer 7

1. Usually a manifestation of quaternary syphilis, but it may also be caused by diabetes mellitus
2. Test for quaternary syphilis using TPHA (Treponema pallidum hemagglutination assay) or FTA (fluorescent treponemal antibody), which remain positive for the duration of the illness
3. Treat with penicillin

Question 8

Tabes dorsalis

Answer 8

1. Caused by 3° syphilis.
2. Results from degeneration (demyelination) of dorsal columns and roots => impaired sensation and proprioception, progressive sensory ataxia (inability to sense or feel the legs => poor coordination).
3. Associated with Charcot joints, shooting pain, Argyll
   Robertson pupils.
4. Exam will demonstrate absence of DTRs and ⊕ Romberg sign.

Question 9

Clinical signs of Oculomotor (III) nerve palsy

Answer 9

1. Ptosis usually complete
2. Dilated pupil
3. The eye points ‘down and out’ due to the unopposed action of lateral rectus (VI) and superior oblique (IV)
4. Test for the trochlear (IV) nerve
   » On looking nasally the eye will intort (rotate towards the nose) indicating that the trochlear nerve is working

Extra points
1. If the pupil is normal consider medical causes of III palsy
2. Surgical causes often impinge on the superficially located papillary fibres running in the III nerve

Question 10

Medical Causes of Oculomotor (III) nerve palsy

Answer 10

1. Mononeuritis multiplex, e.g. DM
2. Midbrain infarction: Weber’s
3. Midbrain demyelination (MS)
4. Migraine

Question 11

Surgical Causes of Oculomotor (III) nerve palsy

Answer 11

1. Communicating artery aneurysm (posterior)
2. Cavernous sinus pathology: thrombosis, tumour or fistula (IV, V and VI may also be affected)
3. Cerebral uncus herniation