neurologic evaluation of anisocoria notes - repaired · neurologic evaluation of anisocoria spencer...
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Neurologic Evaluation of Anisocoria
Spencer D. Johnson, O.D., F.A.A.O.
Northeastern State University
Oklahoma College of Optometry
Overview
• Review the anatomy and neurophysiology that control pupil size and reactivity
• Discuss the etiology of various pupil abnormalities
• Sample case studies and emerging technology
Pupillary Light Pathway
Optic nerve
Optic Chiasm
Optic tract Parasympathetic nucleus of CN III (Edinger-Westphal nucleus)
Ciliary ganglion
Pupillary sphincter
Pretectal nucleus
Retina
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The Autonomic Nervous System
Parasympathetic
• “Fight or flight”
• Ganglia tend to lie closer to the vertebral column
• Dilates the pupil via innervation to the radial muscle of the iris, the dilator pupillae (i.e. iris dilator)
Sympathetic
• “Rest and digest”
• Ganglia tend to lie closer to the effector organ or tissue
• Constricts the pupil via innervation to the sphincter pupillae (i.e. iris sphincter)
• 1st order = central
• 2nd order = preganglionic
• 3rd order = postganglionic
Autonomic Innervation
preganglionic
postganglionic
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Neurotransmitters
Norepinephrine
• Released from post-ganglionic fibers in the sympathetic nervous system
• Recycled, taken back up by the pre-synaptic nerve terminal
Acetylcholine
• Released from post-ganglionic fibers in the parasympathetic nervous system
• Hydrolyzed and inactivated by acetylcholinesterase
Autonomic Innervation
Acetylcholine
norepinephrine
Acetylcholine
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Drugs: Agonists and Antagonists
Adrenergic Cholinergic
• Agonists– Direct
• phenylephrine
• apraclonidine
– Indirect• cocaine• hydroxyamphetamine
• Agonist• pilocarpine
• Antagonist• atropine• cyclopentolate• tropicamide
The Anisocorias
• Benign anisocoria, also known as simple or physiologic anisocoria
• Horner’s syndrome
• Traumatic iris damage
• Adie’s tonic pupil
• 3rd Nerve Palsy with pupil involvement
• Pharmacologically dilated pupil, drug induced mydriasis
Benign Anisocoria
• Occurs in approximately 20% of the population, and may switch sides
• May be more apparent in dim illumination, with difference in pupils usually less than 1 mm
• Thought to occur from unequal supranuclear inhibition of the Edinger-Westphal nucleus
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Horner’s Syndrome
• Occurs from damage to the sympathetic pathway to the eye
• Along with the iris dilator, sympathetic fibers also innervate the superior tarsal muscle (Müllers muscle)
• Triad: ptosis, miosis, anhidrosis
Henry Pancoast
• Worked at the University of Pennsylvania Hospital
• Became the first professor of radiology in the US in 1912
• Certain type of lung cancer named after him
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Smit DP. Pharmacologic testing in Horner’s syndrome – a new paradigm. S Afr Med J 2010; 100: 738-740
Pharmacologic Testing in Horner’s Syndrome
Traditional
• Cocaine– Blocks reuptake of
norepinephrine– If no dilation occurs, then (+)
for Horner’s Syndrome
• Hydroxyamphetamine– Causes release of
norepinephrine from a functioning postganglionic neuron
– Dilation indicates a preganglionc (or central) lesion
Alternative
• Apraclonidine– Dilation with this weak α1-
agonist due to denervation hypersensitivity is positive for Horner’s Syndrome.
• Phenylephrine– Dilation indicates a
postganglionic lesion, due to the absence of monoamine oxidases
Traumatic Iris Damage
• History of ocular surgery
• History of eye injury
http://www.meduweb.com/showthread.php?t=3806
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Traumatic Iris Damage
http://www.meduweb.com/showthread.php?t=3806
Adie’s Tonic Pupil
• Caused by damage to the ciliary ganglion
• Usually idiopathic, unilateral
• Seen most commonly in young females
http://www.nejm.org/doi/full/10.1056/NEJMicm040986
CN III Palsy with Pupil Involvement• Dilated pupil that responds
poorly, or not at all to light
• Complete or incomplete external ophthalmoplegia
• Ptosis
• Must rule-out a compressive lesion when the pupil is involved in a 3rd
nerve palsyhttp://trialx.com/curebyte/2011/08/21/what-is-third-nerve-palsy/
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Pharmacologically Dilated Pupil
• Fixed, dilated pupil
• Will not constrict with 1% pilocarpine
• Potential occupational exposure: nurses, pharmacists, exterminators, etc.
http://www.atlasophthalmology.com/atlas/photo.jsf?node=5820&locale=en
Test pupillary reaction to lightMeasure pupil size in bright and dim illumination
Check for dilation lag
Physiologic Anisocoria
Examine iris under slit-lamp
Traumatic iris damage
Consider 0.125% pilocarpine test
tornnormal
Adie’s pupilpilocarpine 1% test
Third Nerve Palsy Pharmacologic pupil dilation
Constriction No constriction
No constriction Constriction
Good light reaction in both eyesMore anisocoria in dim room
Poor light reaction in one eyeMore anisocoria in bright room
apraclonidine0.5% test
Horner’s syndrome
No dilation lag Dilation lag
Phenylephrine 1%
Aniso reversal
Preganglionic Postganglionic
(-)
DilationNo dilation
Adapted from Smit DP. Pharmacologic Testing in Horner’s Syndrome – a new paradigm. S Afr Med J 2010; 100: 738-740
PERRLA (-)RAPD
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PERRLA• Pupils• Equal• Round• Reactive to Light• Accommodation
Physiologic Anisocoria
PERRLA (-)RAPD
3B/5D
4B/6D
Traumatic Iris Damage
PERRLA (-)RAPD
tear from 3-6 o’ clock
3B/6D
5B/6D
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Adie’s Pupil
PERRLA (-)RAPD
5B/6D
3B/6D
minimal tonic
PERRLA (-)RAPD
Cumbersome?
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The RAPDx Signature is formed from approximately 15,000 data points as pairs of pupillary biometric waveforms
Contrast to the SFT with a single data point of known imprecision.
The new information derived is both clinically useful and easy to obtain.
Signature Key Features
Signature Key Features
StimulusShows chromatic value, duration, eye
Signature Key Features
Constriction Onset LatencyTime from the start of the stimulus
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Signature Key Features
Constriction VelocitySlope from response onset to maximum constriction
Signature Key Features
Constriction AmplitudeFrom resting diameter to maximum constriction –this is the single feature observed with the SFT
Signature Key Features
Recovery VelocitySlope from maximum constriction to resting diameter
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Normal, typical, matching responses
Signature Examples
Normal, typical, very slight anisocoria
(not clinically observable),matching responses
Signature Examples
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