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year 1/2 > Cognition & Senses 2: Neuro-Ophthalmic Exam > Flashcards

Cognition & Senses 2: Neuro-Ophthalmic Exam Flashcards

1
Q

CRANIAL NERVE ____, the ____ NERVE controls MOST of the EXTRAOCULAR MUSCLES, except for which 3?

name those 3’s innervation & action!

A

III, OCULOMOTOR

except for…
1. LATERAL RECTUS = ABDUCENT (CN VI), turns globe AWAY FROM CENTER

  1. RETRACTOR BULBI = ABDUCENT (CN VI), RETRACTS GLOBE into the ORBIT
  2. SUPERIOR (DORSAL) OBLIQUE = TROCHLEAR (CN IV) ROTATES/INTORTS THE GLOBE NASALLY
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2
Q

what innervates the the IRIS SPHINCTER muscle?

what ACTION does this cause?

A

OCULOMOTOR (CN III)

this causes MEIOSIS

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3
Q

what are 2 lesions?

what NERVE likely has a lesion & what does it USUALLY do?

A
  1. PUPIL IS DILATED
  2. eye is LATERALLY DEVIATED (STRABISMUS)

the OCULOMOTOR NERVE, which usually causes CONSTRICTION OF PUPIL & MEDIAL PULL OF EYE

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4
Q

what is the LESION?

what is the NERVE affected & what does it USUALLY do?

A

lesion = eyes are ROTATED/EXTORTED OUTWARD

TROCHLEAR (CN IV) which usually ROTATES/INTORTS GLOBE MEDIALLY

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5
Q

what is the LESION?

what NERVE is affected & what does it USUALLY do?

A

lesion = eye is MEDIALLY DEVIATED

ABDUCENT (CN VI) nerve affected because USUALLY PULLS EYE LATERAL/OUT

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6
Q

INTERNAL OPHTHALMOPLEGIA

= definition

what is usually the PRESENTATION? & why?

A

= when the PARASYMPATHETIC FIBERS of the OCULOMOTOR NERVE (CN III) are DYSFUNCTIONAL/LOSS OF INNERVATION

presents with FIXED, DILATED PUPILS bc CAN NO LONGER CONSTRICT IRIS SPHINCTER MUSCLE in PLR

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7
Q

EXTERNAL OPHTHALMOPLEGIA..

= definition

what PRESENTATION is this usually?

A

= when the SOMATIC/EFFERENT FIBERS in the OCULOMOTOR NERVE (CN III) are DYSFUNCTIONAL

usually presents as LATERAL STRABISMUS

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8
Q

PALPEBRAL REFLEX

= what is it?

involves WHAT 2 NERVES?

what MUSCLE is moved?

what if this is NOT present?

A

= LIGHT touch to the EYE eliciting a BLINK

involves…
1. TRIGEMINAL (CN V)
2. FACIAL (CN VII)

the ORBICULARIS OCULI muscle moves!

if this is NOT present, CAN BE HARD TO DETECT OTHER EYE REFLEXES

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9
Q

CORNEAL REFLEX…

= what is it?

what 3 NERVES are involved?

if this is NOT present, animal can be…

A

= reflex CLOSURE of the LID & GLOBE RETRACTION in response to TOUCHING THE CORNEA

3 nerves?
1. TRIGEMINAL (CN V)
2. ABDUCENS (CN VI)
3. FACIAL (CN VII)

if this is NOT present, animal can be DEAD

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10
Q

NORMAL ordered test for EYE EXAM?

A
  1. start with PALPEBRAL REFLEX to see IF THE ANIMAL CAN BLINK
  2. if so, MOVE TO MENACE RESPONSE
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11
Q

MENACE RESPONSE

why is this NOT a reflex?

= what is it? & what does it TEST in the patient?

what 2 things does the PATIENT require for this to be POSITIVE?

what SPECIES is this less effective in?

A

NOT a reflex because THIS IS A LEARNED RESPONSE

= reflex CLOSURE OF PALPEBRAL FISSURE & TURNING the HEAD AWAY while ONE EYE IS COVERED; this tests VISION

2 things?
1. NORMAL/POSITIVE PALPEBRAL RESPONSE (ability to blink)
2. INTACT VISUAL CORTEX to SEE

this is LESS EFFECTIVE in CATS

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12
Q

when is the MENACE RESPONSE present in…

puppies/kittens?

foals/calves?

A

puppies/kittens = 10-12 WEEKS

foals/calves = 5-7 DAYS

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13
Q

DAZZLE REFLEX…

= what is it?

what 2 NERVES does this involve?

A

= INVOLUNTARY AVOIDANCE REFLEX to a BRIGHT LIGHT shined in the EYE or “SQUINTING”

2 nerves…
1. OPTIC (CN II)
2. FACIAL (CN VII)

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14
Q

PUPILLARY LIGHT REFLEX..

= give an EXAMPLE of DIRECT

= give an EXAMPLE of INDIRECT
–> what could you CALL this?

A

DIRECT = shining LIGHT into the RIGHT EYE and RIGHT PUPIL CONSTRICTS IN RESPONSE

INDIRECT = shining LIGHT into the RIGHT EYE and LEFT PUPIL CONSTRICTS
–> you could call this POSITIVE INDIRECT PLR RIGHT TO LEFT

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15
Q

list 2 DIFFERENT TESTS we can use for VISION TESTING

–> give example for first one

which is NOT ALWAYS indicative of vision?

A
  1. tracking MOVING OBJECTS
    –> COTTON BALL for dogs, LASER POINTER for cats
  2. MAZE TEST
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16
Q

the ____ & ____ REFLEX DO NOT help assess ____, but they DO help evaluate INTEGRITY of ______ pathways

A

PLR, DAZZLE, VISION, NEUROANATOMICAL

17
Q

if a patient has lost the AFFERENT ARM of CN ___, what 3 clinical eye exam signs should we see?

A
  1. VISION LOSS
  2. NO PLR (direct or indirect)
  3. NO DAZZLE REFLEX

CN II (OPTIC)

18
Q

if a patient has lost the EFFERENT ARM of CN ___, what 3 findings should we have? ONE IS NORMAL

A
  1. NO VISION LOSS
  2. ONE eye ALWAYS RESPONDS to PLR & DAZZLE
  3. OTHER EYE DOES NOT RESPOND
19
Q

if a patient has lost the CORTICAL pathway of CN ___, what 3 findings should we have? ONLY ONE IS ABNORMAL

A
  1. VISION LOSS
  2. NORMAL PLR
  3. NORMAL DAZZLE
20
Q

ANISOCORIA definition?

in this presentation, we need to determine WHICH ___ is ____

what 2 TERMS can we use to describe the eyes?

A

ANISOCORIA = UNEQUAL PUPIL SIZE

in this presentation, we need to determine WHICH PUPIL is NORMAL

2 terms?
1. MYDRIASIS = DILATED PUPIL
2. MIOSIS = CONSTRICTED PUPIL

21
Q

if you’re in a LIGHT ROOM and a patient has ANISOCORIA, WHICH pupil is likely ABNORMAL?

A

the MYDRIATIC or DILATED PUPIL is ABNORMAL

22
Q

what are 3 main OPHTHALMIC CAUSES of MYDRIASIS?

what are 4 OTHER CAUSES? (some include eye)

A

3 ophthalmic?
1. OPTIC NEURITIS
2. OPTIC NERVE HYPOPLASIA
3. THIRD NERVE PALSY

4 others?
1. DRUGS (atropine)
2. IRIS ATROPHY
3. COMPLETE RETINAL ATROPHY
4. GLAUCOMA
5. FEAR (especially CATS)

23
Q

MIOSIS causes? (4)

A
  1. UVEITIS
  2. DRUGS (pilocarpine)
  3. ORGANOPHOSPHATE TOXICITY
  4. HORNER’S SYNDROME
24
Q

what DRUG causes…

MYDRIASIS?

MIOSIS?

A

MYDRIASIS (dilation of pupil) = ATROPINE

MIOSIS (constriction of pupil) = PILOCARPINE

25
Q

FACIAL NERVE PARALYSIS…

= definition?

5 clinical signs?

treatment? (3)

A

= INABILITY to MOVE MUSCLES ON FACE

clinical signs?
1. LOSS OF BLINK (can cause EXPOSURE KERATITIS)

  1. NORMAL MUSCLE TONE on CONTRALATERAL SIDE
  2. LIP on AFFECTED SIDE FLACCID
  3. EAR DROOP
  4. DRY CORNEA

treatment?
1. LUBRICATE THE CORNEA
2. if CORNEAL ULCER, use TOPICAL ANTIBIOTIC
3. if VERY SEVERE, then TEMPORARY TARSORRHAPY (sew lids shut)

26
Q

what is GENERALLY normal IOP range in SMALL ANIMALS? (need to include 2 things)

what ALTERNATIVELY could be the range?

A

15-25 mmHg and WITHIN 5 mmHg of EACH OTHER

can also be 10-25 mmHg

27
Q

what is the NORMAL SCHIRMER TEAR TEST range in mm/min for SMALL ANIMALS?

A

15-25 mm/min

28
Q

what is the BASIC DEFINITION of EXPOSURE KERATITIS? & include why it happens

A

when you CANNOT BLINK and the CORNEA DRIES OUT & FORMS ULCERS & INFLAMMATION

29
Q

what is the MOST COMMON ETIOLOGY of FACIAL PARALYSIS in…

dogs?

cats? (2)

what is the prognosis?

A

dogs = IDIOPATHIC

cats? = IDIOPATHIC MAINLY, also NEOPLASIA

PROGNOSIS is GUARDED, depends on the CAUSE!

30
Q

what is a CORNEAL ULCER?

A

when there’s an ABRASION on the CORNEAL SURFACE causing the CORNEAL EPITHELIUM to be GONE

31
Q

HORNER’S SYNDROME..

= definition?

four clinical signs?

A

= the LOSS of SYMPATHETIC INNERVATION to the EYE & ADNEXA

clinical signs?
1. MIOSIS
2. ENOPHTHALMOS
3. PROTRUSION of THIRD EYELID
4. PTOSIS (lid is droopy)

32
Q

why can PTOSIS occur in HORNER’S SYNDROME?

A

due to LOSS OF INNERVATION to MULLER’S MUSCLE IN UPPER LID

33
Q

what is the PATHOPHYSIOLOGY for HORNER’S SYNDROME?

(main pathway & 3 subs)

A

the 3 NEURON PATHWAYS responsible for SYMPATHETIC INNERVATION of EYE & ADNEXA, including…

  1. a FIRST ORDER/CENTRAL NEURON
  2. SECOND ORDER/PREGANGLIONIC NEURON (of the CRANIAL CERVICAL ganglion)
  3. THIRD ORDER/POSTGANGLIONIC NEURON (of the CRANIAL CERVICAL ganglion)
34
Q

if you have FIRST ORDER/CENTRAL LESION causing HORNER’S SYNDROME…

commonality?

A

commonality = UNLIKELY unless you have SERIOUS NEUROLOGIC DZ in THALAMUS, BRAINSTEM or MYELOPATHIC DEFICITS

35
Q

if you have SECOND ORDER/PREGANGLIONIC LESION causing HORNER’S SYNDROME…

commonality?

what 2 STRUCTURES is this SECOND ORDER NEURON close to?

what’s the GANGLION?

A

commonality = more common than first

2 structures?
1. BRACHIAL PLEXUS
2. CAROTID ARTERY

the GANGLION = CRANIAL CERVICAL GANGLION

36
Q

if you have THIRDORDER/POSTGANGLIONIC LESION causing HORNER’S SYNDROME…

what 2 STRUCTURES are near this THIRD ORDER neuron?

what 1 clinical sign can be associated with it?

A

2 STRUCTURES?
1. MIDDLE EAR
2. GUTTURAL POUCH

1 clinical sign?
1. SCRATCHING EARS

37
Q

how do you DIAGNOSE HORNER’S SYNDROME? (2)

what HAPPENS if the PATIENT HAS HORNER’S due a LESION IN THIRD ORDER NEURON?

A

diagnosis?
1. give ONE DROP of PHENYLEPHRINE into BOTH EYES which NORMALLY DILATES PUPILS
2. if one eye DILATES in response to phenylephrine in LESS THAN 20 MINUTES, then POSTGANGLIONIC LESION

if there’s a LESION IN POSTGANGLIONIC NEURON causing HORNER’S, then it will be HYPERSENSITIVE to ANYTHING THAT STIMULATES IT (called DENERVATION HYPERSENSITIVITY), so QUICKER THAN NORMAL MYDRIASIS (dilation)

38
Q

what is the MOST COMMON cause of HORNER’S in….

dogs?

cats? (2)

A

dogs = IDIOPATHIC

cats?
1. HEAD/NECK TRAUMA
2. EAR ISSUES

39
Q

HORNER’S SYNDROME in GOLDEN RETRIEVERS…

WHERE is the lesion?

prognosis?

A

WHERE is the lesion = tends to be a POSTGANGLIONIC/THIRD ORDER NEURON LESION

prognosis = GENERALLY GOOD

year 1/2 (139 decks)

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