MT1 Flashcards
Name for sympathetic problem- pupil won’t dilate in dim lighting
Oculosympathetic paresis/horners
Name for parasympathetic problem- pupil won’t constrict in bright lighting
Internal ophthalmoplegia
Au sign
Think pt is malingering about uveitis. Shine light in normal eye- uveitis eye should still hurt from constriction.
Pathway of neurons from GC axons to edinger westphal
GC axons– optic nerve – chiasm – optic tract (Dessecate)
Some go to LGN, others go to pretectal nucleus in the midbrain.
From pretectal nucleus, fibers travel and descassate at the posterior commissure, then half go to ipsi EW and half go to contra EW
(+) APD? Where is the disease
What should you do if the nerve looks normal?
Anywhere from ganglion cell to anterior knee of the chiasm
Order MRI of the orbits
Indirect APD test
If one pupil is fixed because posterior synechiae or something else- if you shine light into it, look at the consensual response of the other eye. Compare it with direct response of the other eye.
Direct > Consensual of the same, good eye? APD of fixed eye.
2 other ways to determine if pt has an APD
Pupil cycle time- count 100 cycles. 954msec is normal.
RAPDX
Light near dissociated pupil occurs in
- Amaurotic pupil (APD/marcus gun??????)
- Tonic Pupil (affecting ciliary ganglion, large pupil abnormal)
- Argyll Robertson (affecting brainstem, small pupil abnormal)
- Tectal pupils
- Tabes diabetica
- Aberrant regeneration of CNIII
3 steps to eval anisocoria
- Is it pathological or congenital? (Primary essential anisocoria in 15% of population)
- Which eye is abnormal?
- Is it due to the muscle, NMJ, nerve, or brain?
Amaurotic pupil
Completely blind eye with APD/Marcus Gunn
Has light near dissociation
APD is a monocular or biolcular phenomenon
Bi-ocular because when you shine light in the bad eye, both eyes will dilate
Pt presents with poor VA and no APD? 6 things could be causing decreased acuity
- Refractive error
- Media opacities
- Suppression amblyopia
- Stress syndrome
- Macular lesion
- Anterior chiasmal syndrome
What could be the causes of an abnormally dilated pupil?
Paresis of the sphincter (more common)
Dilator irritation- less common
What could be the causes of an abnormally constricted pupil?
Paresis of the dilator (Horners)
Sphicter irritation- common in anterior uveitis
large pupil due to a muscle problem
Posterior Synechiae
Narrow angle glaucoma
Ocular trauma (irido-dialysis)
Law of denervation supersensitivity
When to do this?
Do this if you think your patient has a pharmacological induced dilated pupil!!!! or Tonic pupil!!
Low concentration of pilo.
Normal or pharmacologically dilated eye? No constriction.
Tonic pupil? Constriction
Defect in CN III? NMJ becomes very sensitive to low concentration of ach. Will react more- constrict more than the normal eye.
BUT don’t ever put drops in the eye of someone who has a CN III palsy!!!!!!!!!!!!!!!
Tonic pupil will constrict
So. Abnormally dilated pupil. P sure its not CN III palsy. Do dilute pilo test. No constriction? No synechiae, cyclo-dialysis or glaucoma? 99% sure its due to pharm
Dilute pilo test:
Normal or pharm- no constriction
Tonic or palsy- constriction
What is the most common cause of a fixed dilated pupil?
Drugs
Large pupil due to a nerve problem
- Tadpole pupil. Spasm of the dilator muscle. Goes away in 1-2 weeks
- Tonic pupil
- CN IIII palsy
3 types of tonic pupils that all look the same
- Local- Tumor, varicella infection, damage due to surgery
- Neuropathic - Syphillis, DM, sarcoidosis (people are usually aware they have a disease)
- Aides/Idiopathic
Stats about Aides
Women 20-40
90% unilateral
80% symptomatic - 72% aniso, 35% blurry vision and ciliary muscle related problems
4 qualities to look at size and shape of tonic pupils
Sector paralysis - flat is abnormal
Stromal stream- dynamic. Stream towards working sphincter.
Pigment seam- ectropion is normal
Stromal spread- tight stromal fibers are normal
Ciliary ganglion 30: 1
30 accommodative fibers: 1 pupilomotor
A tonic pupil does not always mean a problem with the ciliary ganglion. Other cause?
Traumatic iridoplegia- damage to short ciliary nerves
Post or preganglionic denervation
Regeneration of CN III
Midbrain oculomotor sign
Supersensitivity testing using accommodation
- Refract to 20/20
- Drop with pilo
- Refract to 20/30
Affected eye will have greater increase in myopia
Pt with aides - how do you treat
Accommodative paralysis?
Accommodative spasm?
pilo
Tropicamide
Holme’s Aides
Ross’s
Aides + Diminished deep tendon reflex
Aides + Diminished deep tendon reflex + excessive sweating
Acute onset of painful CN III palsy with pupil involvement
Aneurysm of posterior communicating artery
*Can start out small, but then blows.
Compresses CN III-pupil fibers on the periphery of the nerve.
Acute onset of painful CN III palsy withOUT pupil involvement
DM of ischemic vascular etiology
Needs medical referral to internist
This occurs because infarct occurs in the core of CNIII, pupil fibers run on the outside of CNIII.
See mixed cranial nerve palsies in 1 eye?
Think MG then cavernous sinus then diabetes
OD larger in bright, and OD smaller in dim?
with and without EOM involvement. Where is the lesion?
With EOM involvement? Think cavernous sinus.
WithOUT EOM involvement? Think ciliary ganglion
Large pupil due to a brain problem
Uncal- Truma, hemorrhage of the uncus in the temporal lobe, which compresses the brainstem/CN III. Likely to lead to death. Always get brain scan after head trauma.
Hutchinsons pupil- fixed dilated pupil associated with Uncal
Parinaud syndrome- Tumor of the pineal gland. See earlier puberty. Near light dissociation.
Hutchinsons pupil is a fixed dilated pupil associated with what
Uncal syndrome- Uncus hemorrhage due to trauma, causing CN III palsy.
Initially, pupil is mitotic, then becomes dilated on the same side as the mass. Can eventually become bilateral.
Signs of parinauds syndrome
Light near dissociated pupil
Convergence retraction nystagmus - attempt to look up, get convergence and nystagmus.
Lid retraction (Colliers sign)
Precocious puberty
