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z Neuro-ophth - Cumulative Bitch > Iris & Pupil Neuro > Flashcards

Iris & Pupil Neuro Flashcards

1
Q

Iris

  • layer containing nerves
  • which nerves and types
A

Stroma

LPCNs = sensory, SNS
SPCNs = PNS, sensory, SNS
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2
Q

Iris

  • which layer contains sphincter muscle
  • innervation of sphincter muscle
A

Stroma

CN3 PNS via SPCNs

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3
Q

Iris

  • which layer contains dilator muscle
  • innervation of dilator muscle
A

Anterior epithelium

SNS via SPCNs and LPCNs

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4
Q

Pupillary disorders
-aniridia
—describe
—assoc condns (3)

A

Hypoplastic iris -> large pupillary opening

Cataracts, glaucoma, vision impairment from macular/ON hypoplasia

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5
Q 
Pupillary disorders
-ectopia lentis et papillae
—describe
—assoc condns (5)
—other ocular signs (3)
A

Rare AR
Bilaterally displaced pupil - usually inferotemporally
Lens dislocation in opposite direction

Severe axial myopia, RD, large corneal diameter, cataract, abnormal transillumination

Microspherophakia, miosis, poor dilation with mydriatics

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6
Q

Pupillary disorders
-ectopic pupils
—describe

A

Idiopathic tractional = fibrous structure tethers the margin to peripheral cornea

May be inherited as isolated ocular finding

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7
Q 
Pupillary disorders
-coloboma
—describe
—possible accompanying ocular sign
—causes (3)
A

Inferior/inferior-nasal notch

Chorioretinal/ON colobomas

Isolation (healthy indiv)
Chromosomal duplication/deletion
Complex congenital disorders (e.g. CHARGE)

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8
Q

Pupillary disorders
-persistent pupillary membrane
—describe

A

Spoke-like opacities across pupil

Derive from tunica vasculosa lentis

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9
Q

Anterior chamber cleavage anomalies

  • assoc with
  • Peter’s
  • Rieger’s
A

Mis-shapen pupils + abnormal adhesions between cornea and iris

P: central corneal defects

R: peripheral corneal defects

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10
Q

Pupillary light pathway

  • afferent = __ -> __
  • efferent = __
A

Retina -> EW nucleus

PNS pathway

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11
Q

Pupillary light pathway
-afferent pupillary pathway
—pupillary fibers travel __ as far as __, with nasal crossing at the chiasm
—fibers exit __ and travel within the __ to __
—fibers then travel to __, with those that cross to the opposite travelling in the __

A

Travel with visual fibers -> posterior optic tract

Exit posterior 1/3 of optic tract, travel within brachium of superior colliculus to pretectal nucleus and synapse

Travel to BOTH EW nuclei - those that cross to opposite nucleus travel in posterior commissure

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12
Q

Pupillary light pathway
-efferent pupillary pathway
—preganglionic fibers leave __ with __ and follow __ into the orbit
—PNS fibers leave and enter __
—postganglionic fibers travel with __ to anterior eye to innervate __

A

Leave EW nucleus (MB) with motor fibers of CN3 and follow inferior division into orbit

Leave inferior division, enter ciliary ganglion, and synapse

Travel with short ciliary nerves -> anterior eye -> sphincter and ciliary muscle (accomm)

(EW -> CN3 inferior division -> ciliary g + synapse -> short ciliaries -> sphincter, ciliary muscles)

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13
Q 
Disruption of afferent pathway
-RAPD
—causes
—appearance
—assoc with
A

Optic tract lesion = contralateral APD
Also: RD, ischemic CRVO, ON ischemia or compression, optic neuritis, asymmetric glaucoma

Amaurotic/deafferented pupil

Vision loss

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14
Q

Disruption of afferent pathway
-pretectal pupil
—when it’s seen
—signs

A

Lesions affecting dorsal MB -> Parinaud syndrome

Usually bilateral, asymmetric
Upgaze paresis, head tilt
Contralateral APD + light-near dissociation

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15
Q

Disruption of afferent pathway
-accommodation-Convergence Reaction Pathway
—afferent
—efferent

A

A: retina -> EW nucleus -> striate cortex -> FEF -> CN3+EW nuclei

E: PNS pathway (EW -> CN3 inferior division -> ciliary g -> synapse -> anterior eye)

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16
Q 
Disruption of afferent pathway
-Argyll-Robertson pupil
—laterality
—how
—pupil testing
—appearance
—causes
A

Bilateral, asymmetrical

Interrupt fibers from pretectal nucleus to PNS nucleus

Poor direct, normal consensual, light-near dissociation

Miosis evident in darkness - fibers carrying inhibitory feedback to PNS travel here (no dilation with atropine, either)

Diabetic ret, alcoholic neuropathy, neurosyphilis

17
Q

Disruption of efferent pathway
-CN3 palsy/oculomotor impairment
—relationship of CN3 and PNS fibers and implications
—dilated pupil + CN3 involvement

A

PNS are superficial to CN3 as emerge from MB
-PNS fibers are often spared in ischemic lesions (e.g. DM), but are susceptible to compression

Highly suspicious of a compression intracranial lesion (aneurysm)

18
Q 
Disruption of efferent pathway
-tonic pupil
—site of damage
—pupillary testing
—other signs
—diagnostic testing
A

Ciliary ganglion or short ciliary nerve

Poor light reponse + loss of accommodation

Decr corneal sensitivity

Administration of 1% pilocarpine (cholinergic agonist) will constrict it

19
Q 
Disruption of efferent pathway
-Adies tonic pupil
—cause
—who
—progression
—diagnostics
A

Idiopathic

Women 20-40

Becomes smaller, doesn’t dilate well in dark

Significant miosis with 0.125% pilocarpine due to sphincter hypersensitivity

20
Q

Disruption of efferent pathway
-tonic pupil management
—testing
—elderly pts

A

FTA-ABS or MHA-TP for neurosyphilis

ESR + CRP to screen for GCA in elderly

21
Q

Pharmacological dilation

  • gtts (4)
  • others/non-drops
  • a quick test
A

Atropine, tropicamide, cyclopentolate, phenylephrine

Scopolamine patch, ipratropium, jimson weed, blue nightshade, angels trumpet, visine/clear eyes

1% pilo will fail to dilate

22
Q

Unreactive pupils
-angle-closure glaucoma
—when narrow-angle pt has emergent IOP, apply 1% pilo to incr AH outflow

A

False - breaks posterior synechiae, but doesn’t incr outflow

23
Q

Sympathetic pathway for pupillary dilation

  • SNS fibers are controlled by
  • SNS innervation originates in
  • preganglionic synapse
  • postganglionic fibers form
A

Hypothalamus

T-1 thru T-3

Superior cervical ganglion

Carotid plexus around internal carotid a

24
Q

Sympathetic pathway for pupillary dilation

  • orbital fibers leave carotid plexus
  • SNS fibers follow __ -> __ -> __
A

In cavernous sinus*

Follow nasociliary n -> long ciliary n -> dilator + ciliary muscles (inhibits ciliary)

*3,4,6, V1, V2 - V3 and 7 do not go thru

25
Q

Horner’s

  • disruption of __
  • signs
A

Efferent/SNS dilation

Mild ptosis, facial anhidrosis, miosis
Dilation lag in dim light
Normal reaction to light and near stimuli

26
Q 
Horner’s
-central
—neuron
—common cause and appearance
—uncommon cause and appearance
A

1st order

Common = lateral medullary stroke (Wallenberg syndrome)

  • Horner’s ipsilateral to lesion in 3/4 cases
  • defective smooth pursuit, ataxia, torsional or horiz nystagmus

Uncommon = mesencephalic + pontine lesions
-Horner’s + contralateral CN4 palsy

27
Q 
Horner’s
-preganglionic
—neuron
—common cause and appearance
—less common cause
A

2nd order

Pancoast tumor
-ipsilateral Horner’s

Brachial plexus injury

28
Q 
Horner’s
-postganglionic 
—neuron
—common causes and appearance (2)
—other cause
A

3rd order

Carotid dissection
-ipsilateral HA/pain, ocular/cerebral ischemia
-Horners ~50%
Cavernous sinus lesions
-Horners + any combo of ipsilateral CN3,4,6,V1,V2 involvement

Other: small vessel ischemia

29
Q

Horner’s
-pharmacological testing
—cocaine
—hydroxyamphetamine

A

C: 5-10%

  • constriction = no problem
  • no response = problem, non-specific location

H: 1%

  • no response = 3rd order neuron (postganglionic)
  • dilation = 1st/2nd order neuron (preganglionic)
30
Q

Horner’s
-congenital
—causes (2)
—appearance

A

Neuroblastoma, birth trauma

Heterochromia - normal iris pigmentation fails to develop

31
Q

Pupillary disorders of other neurologic conditions

  • coma
  • opiates
  • migraine
A

Structured lesion

Pinpoint

Adilated pupil + ipsilateral HA

32
Q

Pupillary disorders of other neurologic conditions
-seizures
—general tonic-clonic
—epileptic focus

A

Bilateral mydriasis

Ictal unilateral mydriasis

33
Q

Other pupillary disorders

-westphal-piltz reflex

A

Constriction in darkness (normal in sleep)

34
Q

Other pupillary disorders

-paradoxic constriction in darkness

A

May suggest a retinal dystrophy (congen stationary night blindness, achromatopsia)

35
Q

Other pupillary disorders

-tournays

A

Induced by lateral gaze
<10% of population
Pupil of abducting eye > adducting eye

36
Q

Other pupillary disorders

-oculosympathetic spasm

A

Irritation of OS pathway -> unilateral mydriasis +/- ipilateral facial flushing, lid retraction, hyperhidrosis

37
Q

Other pupillary disorders

-tadpole-shaped pupil

A

Episodic mydriasis with segmented distortion
Intact light constriction
Abnormal spasm of dilator

z Neuro-ophth - Cumulative Bitch (10 decks)

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