8.1 Pupils Flashcards
(105 cards)
1
Q
What is an efferent pupil defect? Any key features?
A
Motor defect; lesion to system carrying signal from CNS to iris
Key feature: anisocoria
2
Q
What is an afferent pupil defect? Key features?
A
Lesions in the initial signalling pathway (usually retina or optic nerve)
Key features: abnormal signalling reflexes, no anisocoria
3
Q
Mydriasis mechanism? (including neurotransmitters and receptors)
A
Mydriasis = dilation
Excite sympathetic system, inhibit parasympathetic
Norepinephrine acts on α-adrenergic receptors and stromal elastic expansion
4
Q
Miosis mechanism? (including neurotransmitters, receptors)
A
Miosis = constriction
Excite parasympathetic, inhibit sympathetic
Acetylcholine acts on muscarinic receptors
5
Q
Equal pupil sizes in light and dark indicates ….
A
Normal light reflex, normal pupils
6
Q
Unequal pupil size
In light: OD is 5mm, OS is 6mm
In dark: OD is 7mm, OS is 8mm
A
Normal light reflex, physiological anisocoria
Disparity is the same in light and dark conditions and is less than 2mm (could still be physiological anisocoria if >2mm but very uncommon)
7
Q
Light on right eye: OD 5mm, OS 5mm
Light on left eye: OD: 3mm, OS 3mm
No light perception in right eye
A
Absolute afferent pupil defect (OD affected in this case)
8
Q
Swinging flashlight test
Light on right eye: OD: 3mm, OS 3mm
Light on left eye: OD: 4mm, OS 4mm
A
Relative afferent pupil defect (OS affected in this case)
9
Q
Abnormal light reflex, no light perception
A
absolute APD
10
Q
Abnormal light reflex, light perception is fine
A
Relative APD
11
Q
Abnormal light reflex, bilateral, near reflex normal
A
Argyll Robertson pupil (efferent defect)
12
Q
Abnormal light reflex, bilateral, near reflex abnormal
A
Drug induced pupil issue likely, efferent
13
Q
Abnormal light reflex, anisocoria, no ptosis, near defect
A
Adie’s tonic pupil (efferent)
14
Q
Abnormal light reflex, anisocoria, no ptosis, intermittent near defect
A
Tourney phenomenon (efferent)
15
Q
abnormal light reflex, anisocoria, no ptosis, no near defect, no trauma or drugs
A
Hutchinson’s pupil (efferent)
16
Q
abnormal light reflex, anisocoria, no ptosis, no near defect, trauma
A
Iris sphincter damage (efferent)
17
Q
abnormal light reflex, anisocoria, no ptosis, no near defect, drugs
A
Pharmacological pupil (efferent)
18
Q
abnormal light reflex, anisocoria, ptosis, + (XOT - down and out eye position)
A
3rd nerve palsy (efferent defect)
19
Q
abnormal light reflex, anisocoria, ptosis, anhydrosis
A
horner syndrome (efferent defect)
20
Q
Pupils are equal in size in _____ pupillary defects
A
afferent
21
Q
Ocular associations of afferent pupil defects
A
reduced VA, colour vision defects, central visual field defects, abnormal VEP (visual evoked potential)
22
Q
Minor causes of afferent pupil defect ?
A
Very mild: amblyopia, vitreous hemorrhage
Mild: macular degeneration, BRVO/BRAO, retinal detachment, other retinal disease
(BRVO/BRAO = branch retinal vein/artery occlusion)
23
Q
Major causes of afferent pupil defects
A
(think nerves and blood)
- Optic nerve disease: ischemic optic neuropathy (ION), optic neuritis, optic atrophy, tumour, glaucoma)
- Ischemic CRVO/CRAO (central retinal vein/artery occlusion)
- RAPD: optic chiasm and tract lesions (infarcts, demyelination)
24
Q
Absolute afferent pupil defect (type of lesion, alternative name)
A
Complete optic nerve lesion
aka amaurotic pupil
25
Absolute afferent pupil defect (signs)
Pupils equal in size
Involved eye is blind (no light perception)
Normal eye stimulated with light = normal light response in both eyes (constriction). Affected eye stimulated = no response/change
Normal near reflex
26
relative afferent pupil defect (what it is)
RAPD = objective sign of asymmetric lesion in anterior visual pathway
27
relative afferent pupil defect (cause)
incomplete optic nerve lesion or severe retinal disease (usu. optic nerve conduction defect)
NEVER due to a dense cataract
28
relative afferent pupil defect (signs)
Like an absolute afferent pupil defect but not as severe
Swinging flashlight test: both eyes constrict when light shone in normal eye. both eyes dilate when light shone in affected eye. Affected eye's consensual response \> direct response so affected eye responds as if the light is dimmer; termed pupillary escape
29
What is the near reflex?
Pupils constrict with convergence, dilate with divergence
30
What is the light-near dissociation?
normal near reflex but abnormal or sluggish light reflexes
31
If _____ reflex is normal, the ____ reflex will be normal (but the converse is not true)
light, near
32
Argyll Robertson pupil (causes, association)
neurosyphilis (tertiary syphilis)
Ocular assocations: interstitial keratitis
Systemic associations: (+) syphilis serology
33
Argyll Robertson pupil (signs)
Small irregular pupils that show light-near dissociation
Usually bilateral but may be asymmetrical
Poor reaction to light (constriction and dilation
Poor dilation with mydriatic
Normal constriction with convergence
34
pharmacological pupil defects (reflex responses, type)
abnormal light response
abnormal near response
(efferent defect)
35
pharmacological pupil can be ______ or \_\_\_\_\_\_\_
unilateral or bilateral
36
right pharmacological pupil
37
pharmacological pupil, unilateral, miosis -\> what drug will cause this?
pilocarpine
38
What drug(s) will cause pharmacological pupil, unilateral, mydriasis?
Mydriacyl, tropicamide, cyclogyl, cyclopentalate
39
What drugs will cause bilateral pharmacological pupils, miosis?
Systemic drugs (8): caffeine, chloryl hydrate, chlorpromazine, histamine, MAO inhibitors, morphine, nicotine, opiates
40
What causes bilateral pharmacological pupil, mydriasis?
Systemic drugs: amphetamines, antihistamines, cocaine, benedryl, LSD, marijuana, tricyclic antidepressants
41
What is anisocoria?
Unequal pupil size; abnormal pupil may be smaller or larger
42
Anisocoria suggests ...
Efferent (motor) defect but need to look at eyelid position and EOM
43
Anisocoria examination (2 main components)
Case Hx and ocular examination
44
Anisocoria examination -\> Case Hx questions
1. Onset (may look at photographs)
2. S/Sx? (Reduced VA, ptosis, EOM disorders, iris heterochromia)
3. trauma? (esp to eye/head)
4. eye drops/ointment?
5. Syphilis?
45
Anisocoria - ocular examination tests
Pupil assessment (light & near, RAPD)
Pupil size in light and dark conditions (anisocoria greater in light = larger pupil is abnormal; anisocoria greater in dark = smaller pupil abnormal)
Ptosis, ocular motility
Pupillary margin examination (slit lamp)
Pharmacological testing
46
Cause of anisocoria, miosis (abnormal pupil constricted)
Unilateral use of green top (miotic) for glaucoma
Iritis
Horner's syndrome
Argyll Robertson pupil
47
What causes anisocoria, mydriasis (abnormal pupil is dilated)?
Unilateral use of red cap (mydriatic) by nurses, due to drugs, insecticides
Trauma (iris sphincter damage)
Tonic pupil (idiopathic = Adie's)
CN3 palsy
48
Anisocoria but difference in light and dark conditions is the same
Physiological pupil
49
What is a 3rd nerve palsy?
Any interruption of the 3rd nerve pathway
50
What muscles are functional in a 3rd nerve palsy?
Functional: SO (abduction, depression, internal rotation) and LR (abduction)
51
What muscles aren't functioning in a 3rd nerve palsy?
Non-functional: SR, MR, IR, IO, levator, sphincter
52
Signs of a 3rd nerve palsy
Ptosis, mydriasis, cycloplegia, exotropia
-may see exotropia and depression in patients (despite SO have no depressor function in abduction)
53
3rd nerve palsy effects on lids, primary gaze, abduction, adduction, elevation, depression
Lids: ptosis
Primary gaze: down and out no MR = XOT, wall eyed)
Abduction: normal (LR is functioning)
Adduction: limited (MR not functioning)
Elevation: limited (no SR or IO)
Depression: limited (no IR)
54
3rd nerve palsy and normal pupil suggests ... (cause, key features, and prognosis)
Microangiopathy (hypertension, diabetes)
Periorbital pain common and may be presenting sign in DM
Prognosis: usu. spontaneous recovery w/in 3 months
55
3rd nerve plasy and dilated pupil suggests .... (cause, key features, prognosis)
Pupil involvement = Nerve compression (aneurysm, trauma)
Pain often presents with aneurysm
Life-threatening \> requires immediate MRI and neurological examination
56
What is Horner syndrome?
Oculosympathetic palsy; disruption of EFFERENT sympathetic pathway
57
Is Horner syndrome congenital or acquired?
Can be either but recent onset (ie. acquired) is very suspicious
58
Signs and symptoms of Horner syndrome?
Often asymptomatic
"Ptosis, miosis, anhydrosis" triad
* Ptosis: upper lid droops, lower lid elevated
* Miosis: pupil constricted on affected side
* Anhydrosis: not sweating on affected side (bc external carotid artery plexus affected)
Iris heterochromia (for CONGENITAL only, lighter on affected side)
Pupils: light and near reflex normal, no RAPD, pathognomic dilation lag in dim light
59
3rd nerve palsy may involve ____ system and Horner syndrome involves ____ system
parasympathetic, sympathetic
60
Preganglionic vs postganglionic acquired horner syndrome etiologies
Implication for prognosis?
1st order and 2nd order are preganglionic
3rd order is postganglionic
Better prognosis is postganglionic (rather than preganglionic)
61
Pathognomic sign of Horner syndrome?
* Dilation lag in dim light
* affected eye = slower dilation
* anisocoria most obvious after 4-5 seconds; less obvious after 10-12 secs
(Also have normal light and near reflexes, no RAPD)
62
Acquired horner syndrome: 3 types of etiology
* 1st order: stroke, tumours
* 2nd order: Pancost lung tumour, neuroblastoma (children)
* 3rd order: cluster migraine, HZV, cavernous sinus tumour
63
1st order Horner Syndrome etiology
(1st order = central neuron, preganglionic)
Stroke, tumour
64
2nd order acquired Horner syndrome etiology
Tumours (lung carcinoma aka Pancost, thyroid/neck adenoma)
If arm pain, suspect Pancoast tumour (lung)
If child, suspect neuroblastoma
[2nd order runs from the spinal cord to the superior cervical ganglion]
65
Relevant anatomy to Horner syndrome
The pupil is innervated by sympathetic and parasympathetic fibers. Pupillary dilation is mediated by a three- neuron sympathetic pathway that originates in the hypothalamus.
```
_1st order (central) neuron_: runs from **hypothalamus -\> cervical spinal cord** (C8-T2)
_2nd order neuron_: **spinal cord** -\> cervical sympathetic chain through brachial plexus, over pulmonary apex **-\> synapse in superior cervical ganglion** (near mandible angle, common carotid bifurcation)
_3rd order (postganglionic) neuron_: **superior cervical ganglion -\> iris dilator** muscle, Muller's muscle in upper and lower lid (travels on outside of internal carotid artery into the cavernous sinus. Here the oculosympathetic fibers join trigeminal V1 division to enter the orbit. The fibers (long ciliary nerve) innervate the dilator and Müller’s muscle)
```
Pupillary constriction is produced by parasympathetic (cholinergic) fibers that travel with the third cranial (oculomotor) nerve.
66
3rd order acquired Horner syndrome etiology
Postganglionic (better prognosis)
Cluster migraine HZV, cavernous sinus tumour
67
Horner Syndrome diagnosis (list the method(s))
2-10% cocaine test, bilaterally, 1gt OU: (+)ve confirms Horner syndrome
1% hydroxyamphetamine: locates lesions (1st, 2nd, or 3rd order)
Radiological work up: differentiate 1st and 2nd order
68
How do you test for presence of Horner syndrome? Why do you use that particular test?
2-10% cocaine test, bilaterally, 1gt OU
Horner pupil dilates less than normal pupil bc no postganglionic neurotransmitters are being released
Cocaine only causes pupil dilation if norepineprhine is present/released at postganglionic nerve endings in the iris dilator muscle. Cocaine blocks reuptake of NE which leads to dilation of unaffected eye
69
For Horner syndrome, what is the first test that you would use to *localize* the lesion?
1% hydroxyamphetamine (Paredrine) =\> test will differentiated pre-ganglionic from post-ganglionic
Test is done **at least 24 hrs after** cocaine test
1gt OU, repeat 1 minute later
Watch for dilation of suspected pupil after 30 minutes. If no dilation of suspected pupil = 3rd order (post-ganglionic).
Hydroxyamphetamine will not cause pupillary dilation if post-ganglionic pathway is disrupted
70
For Horner syndrome, what is the second test that you would use to localize a lesion?
Radiological work up =\> differentatie between 1st and 2nd order defects (both are pre-ganglionic)
Will differentiated between internal carotid aneurysm (1st order) and Pancoast tumour (apical lung tumour, 2nd order)
71
10% cocaine - pupil dilates
Dx: normal
72
Cocaine 10% - eye does not dilate as much (impaired dilation)
Dx: Horner syndrome
73
Hydroxyamphetamine 1% - eye dilates
Normal OR preganglionic Horner syndrome
74
Hydroxyamphetamine 1% - eye does not dilate
Postganglionic Horner syndrome
75
Mydriatic - eye does not dilate much (poor dilation)
Argyll Robertson pupil
76
Mydriatic - eye dilates
Normal
77
What is a tonic pupil?
Dilated pupil that reacts poorly to light and accommodation; shape often distorted
78
Etiology of tonic pupils?
Dilated pupil with poor light response/accommodation due to a postganglionic lesion (denervation of parasympathetic supply to sphincter & ciliary muscle)
79
Types/causes of tonic pupils
Trauma
Infection (Herpes Zoster)
Diabetes
Idiopathic (Adie's)
80
Tonic pupils are very sensitive to .....
Dilute cholinergic agents (ie. pilocarpine)
81
Prevalence of Adie's tonic pupil
~2 per 1000, usually young women (80%) with a Hx of mild URT infection (upper respiratory tract)
82
Adie's tonic pupil is associated with ....
Loss of deep tendon knee reflexes (sometimes)
83
What is the cause of Adie's tonic pupil and implications?
Damage to ciliary ganglion or postganglionic parasympathetic fibres
Heightened sensitivity to cholinergic agents (denervation supersensitivity) -\> tonic pupils constrict to 0.125% pilocarpine (normal eye unaffected)
84
What are the signs of Adie's tonic pupil?
Unilateral, irregular, slightly dilated pupil
Poor light reflex (direct and consensual)
Impaired near reflex (slow convergence and accommodation; slow tonic re-dilation as Pt shifts gaze from near to far)
Unilateral blurred vision due to decreased accommodation (may req assymmetric reading adds)
Affected pupil becomes smaller over time (may eventually be smaller than the normal pupil, "little old Adie")
85
Adie's tonic pupil - what is its reaction in bright light vs dim light?
Anisocoria greater in bright light than in dim (miosis is impaired bc this is a parasympathetic efferent defect)
86
Adie's tonic pupil - near reflex response?
Near reflex intact but slow (accommodative neurons re-innervate iris sphincter)
87
0.125% pilocarpine added OU but only OD constricts
OD is Adie's tonic pupil
88
What is Tournay phenomenon?
Lateral gazes induce an enlarged pupil in abducting eye
89
Pathophysiology of Tournay phenomenon
Anomalous innervation of the iris sphincter by the neurons intended for the ipsilateral medial rectus (co-innervation)
Inhibition of MR during lateral gaze thought to inhibit sphincter in abducting eye
90
Tournay phenomenon - etiology, frequency, associations
Congenital
Rare
No known associations
91
Signs of iris sphincter damage?
Hx of ocular trauma
Torn pupillary margin (traumatic mydriasis)
Iris transillumination defects
Hyphaema
92
What is Hutchinson pupil (including key features)?
Affected pupil unresponsive to light, fixed, and widely dilated (other pupil contracts normally)
Due to a intracranial lesion (e.g. lesion compressing the 3rd nerve)
93
Causes of Hutchinson pupil
Usually severe head injury
Also: stroke, brain tumour, abscess, edema, skull fracture (bilateral dilation)
94
Pilocarpine 0.1% - eye constricts
Adie's tonic pupil
95
Pilocarpine 0.1% - no reaction (no constriction)
Normal
96
Pilocarpine 0.5% - eye constricts
Not pharmacologically dilated
97
Pilocarpine 0.5% - no constriction/reaction
Pharmacological dilation
98
What is physiological anisocoria?
Bilateral pupil inequality
Small disparities are normal (in about ~20% of population)
99
Signs of physiological anisocoria
Size difference usually \<2mm; unlikely to see differences of 0.4mm or less
So, expect differences of 0.5mm-2mm
Pupil size disparity is the same in light and dark
Normal light reflexes, no RAPD, normal accommodation response
100
anisocoria greater in light
larger pupil is abnormal
101
anisocoria greater in dark
smaller pupil abnormal
102
What is the Horner syndrome triad?
"Ptosis, miosis, anhydrosis" triad
Ptosis: upper lid droops, lower lid elevated
Miosis: pupil constricted on affected side
Anhydrosis: not sweating on affected side (bc external carotid artery plexus affected)
103
What is unusual about the ptosis in Horner syndrome?
There is lower lid elevation (along with upper lid depression)
104
What symptoms appear in Horner syndrome? (symptoms not signs)
Usually asymptomatic
105
What other signs appear in Horner's syndrome besides the triad? (2)
Iris heterochromia (for CONGENITAL only, lighter on affected side)
Pupils: (besides miosis) light and near reflex normal, no RAPD, pathognomic dilation lag in dim light
