NBEO: Boards: Neuroscience Flashcards

1
Q

NTs

  1. Which NT is the most widely distributed INHIBITORY transmitter?
  2. Which NT is found in the brainstem, spinal cord, and RETINA and is INHIBITORY?
  3. Which is found in Skeletal muscle and blocked by CURARE?
  4. Which is found in Sm. Muscle?
  5. Which are found in the SNS?
  6. What Receptors are TARGETED by a-Bunagarotoxin (snake Venom)?
A
  1. GABA
  2. Glycine
  3. Cholinergic: Nicotinic
  4. Cholinergic: Muscarinic
  5. Adrenergic NTs
  6. Nicotinic Ach Receptors (NMJ and PSNS)
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2
Q

Define the Following: PNS

  1. Ganglia
  2. Nerves
  3. Sensory Division
  4. Somatic Motor Division
  5. Autonomic Motor Division
A
  1. collection of nerve cell bodies
  2. bundles of axons
  3. Ganglia that lie near the spinal cord or brainstem
  4. neurons that innervate skeletal muscle
  5. Neurons that innervate cardiac and SM and glands. SNS and PSNS
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3
Q

CNS: Define

  1. Nuclei
  2. Cortex
  3. Frontal Lobe
  4. Parietal Lobe
  5. Occipital Lobe
  6. Temporal Lobe
A
  1. Collection of neurons (like ganglia)
  2. layers of cells
  3. Premotor cortex (Planning and execution of motor tasks). Personality (reasoning, planning). Broca’s AREA (speech conduction)
  4. Sensory and Recognition
  5. Vision
  6. Perception and Sensory Recognition (auditory, speech) and Memory. *Hippocampus; Wernicke’s Area (speech recognition)
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4
Q

Spinal Nerves

  1. Cervical
    a. 1-4?
    b. 5-8?
  2. Thoracic
    a. 1-12?
  3. Lumbar
    a. 1-4?
    b. 4-5?
  4. Sacral
    a. 1-3?
    b. 2-4?
  5. Coccygeal?
A
  1. a. Neck
    b. Upper Extremities
  2. a. Upper extremities
  3. a. Thigh
    b. Thigh,leg,foot
  4. a. thigh, leg, foot.
    b. pelvis
  5. Coccygeal nerve
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5
Q

Brainstem

  1. Medulla: purpose?
  2. Pons?
  3. Midbrain?
A
  1. Autnomonic stuff (hear rate, digestion, breathing)
  2. coordinates movement info b/w cerebral hemispheres and cerebellum
  3. sensory and motor functions: COORDINATION of EYE MOVEMENT and VISUAL REFLEXES!
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6
Q

Medulla

  1. Upper medulla: 2 main structures it contains and what tracts do they have?
  2. The latter part has what tracts and what info do they carry?
  3. What does the MLF relay?
  4. Lower/Middle Medulla: Location of what Nuclei?
A
  1. Pyramids (Ventral and Descending) and Medial Lemniscus (Ascending Dorsal Tracts)
  2. Gracilus (lower body info) and Cuneate Fasciculi (Trunk info) (tracts) **Start to see 4th Ventricle
  3. Vestibular info to EXTERIOR EYE MUSCLES; Coordinates the VOR
  4. Vestibular Nuclei and Olivary Nuclei (Learning and memory)
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7
Q

Pons

  1. Purpose?
  2. What nuclei are found here?
  3. What else is the pons involved in?
  4. CNs found here?
A
  1. Relay info b/w midbrain and Medulla
  2. Pontine Nuclei (relay stations for motion-related info that goes b/w the cortex and cerebellum)
  3. Controls respiration and sleep
  4. Nuclei for CNs 5-8
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8
Q

Midbrain

  1. Upper Midbrain: Location of what?
  2. Lower Midbrain: Contains what?
A
  1. a. Superior Colliculus (has motor neurons that control orientation of the HEAD/EYES)
    b. Red Nucleus (Controls arm movement and Oculomotor nuclei)
    c. EW-Nucleis (CN 3): PSNS innervation to the IRIS!
  2. a. Inferior Colliculus (reflex response of head/neck to auditory stimuli)
    b. CN 4 nucleus (C/L SO)
    c. Start to see Cerebellar peduncles (Tracts going to Cerebellum)
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9
Q

Neural Tube

  1. 3 General Areas?
  2. Which differentiates into the TELENCEPHALON and DIENCEPHALON?
  3. What gives rise to the Cerebral Hemispheres?
A
  1. Forebrain, Midbrain, Hindbrain
  2. Forebrain
  3. Telencephalon
    * So, forebrain gives rise to the diencephalon and cerebral hemispheres.
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10
Q

Midbrain

  1. Diencephalon
  2. Epithalamus
  3. Thalamus
  4. Subthalamus
  5. Hypothalamus
A
  1. Epithalamus, Thalamus, Subthalamus, and Hypothalamus
  2. Pineal Gland (melatonin)
  3. Relays sensory info to Cortex; also has Nuclei for voluntary motor movements
  4. communicates w/basal ganglia: helps control muscle movement
  5. regulates body temperature, eating, and sleep behavior.
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11
Q

Cerebral Hemispheres

  1. Dominant Hemisphere
  2. Non-Dominant Hemisphere
A
  1. More control over understanding, processing language, intermediate and long-term memory, word retrieval, and emotional stability
  2. Facial expression recognition, Vocal intonation, music, visual learning
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12
Q

Cerebellum

  1. Purpose
A
  1. fine motor movements, posture, balance
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13
Q

Blood Supply

  1. Main Blood supple by what 4 arteries?
  2. Vertebrals
    a. Originate from what Arteries?
    b. Rt and Lt join to form what ARTERY? Supplies what?
    c. This artery then joins the Carotids at what?
  3. Internal Carotids
    a. Arise from what arteries in the neck?
    b. These branch into what and supply what area of the brain?
  4. Circle of Willis
    a. Joins what arteries?
A
  1. Internal Carotids and Vertebral Arteries…all meet by the Pituitary gland
  2. a. Subclavian arteries (blood to spinal cord)
    b. BASILAR ARTERY (blood to pons)
    c. Circle of Willis
  3. a. Common carotid arteries in the neck; Lt common comes off the AORTIC ARCH; the Rt Common comes off the Braciocephalic Trunk
    b. ICAs branch into ANTERIOR and MIDDLE CEREBRAL ARTERIES: supply blood to FOREBRAIN
  4. a. ICAs, Basilar, and Anterior and Posterior Communicating Arteries
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14
Q
  1. What tests help us determine if ON damage is present (2)?

2. What test is used to evaluate for Macular Damage?

A
  1. Brightness comparison and Red-Cap Desaturation

2. Photostress Test

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15
Q

Name 3 ways an ON that’s unhealthy can present itself

A
  1. Atrophic (Excavated or Pallid (Primary = not previously edematous))
  2. Edematous
  3. Normal (Retrobulbar Optic neuritis, PION)
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16
Q

Disc Edema

  1. Posible Signs (6)
  2. Pathogenesis: Cause?
  3. What are the most common causes (7)
A
  1. APD, VF defect, decreased acuity, blurred disc margin, nerve fiber elevation, hemes.
  2. PRE-CHIASMAL DISRUPTION of Axoplasmic Flow
  3. a. AION (AAION and NAION)
    b. CRVO
    c. Compressive Lesion (Meningioma, TED, Lymphoma, Hemangioma)
    d. Diabetic Papillopathy
    e. Hypotony
    f. Optic Neuritis (Papillitis (Anterior) and Retrobulbar (Post. 2/3 of nerve): Causes: MS, Viral, Toxoplasmosis, Sarcoid, Syphilis, Tb, Non-infectious uveitis, Idiopathic
    g. Papillophlebitis
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17
Q

PAPILLEDEMA

  1. Signs: Blurred disc margins, elevated/opaque NFL, No Spontaneous Venous Pulsation, and What else?
    a. How is VA in the early stages?
  2. Pathogenesis: ?
  3. Most Common Causes (5)
A
  1. Splinter hemes, Paton’s Folds (circumferential retinal folds), exudates, CWS, Venous distention, and hyperemia of the disc.
    a. Normal
  2. Increased Cerebrospinal fluid pressure in Subarachnoid space of the intraorbital part of the ON. This causes AXOPLASMIC Stasis
  3. a. Malignant HTN
    b. Post-Chiasmal Tumor
    c. Inflammatory (Infectious (Meningitis) and Non-Infectious (Sarcoidosis)
    d. Pseudotumor Cerebri
    e. Compromised or Obstructed Venous Outflow
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18
Q

Atrophic Optic Nerve (U/L or B/L)

  1. Pathogenesis
  2. Types of ON Atrophy (2)?
  3. Causes of Pallor of the Rim: Primary Optic Atrophy (5)
  4. 2ndary Optic Atrophy Causes?
A
  1. Destruction or degeneration of the optic nerve axons
  2. Excavated (Glaucoma) and Pallid (Flat/whitish in color)
  3. a. Hereditary (Leber’s, Dominant Optic Atrophy)
    b. Orthograde Degeneration (Eye to Brain)
    c. Retrograde Degeneration (brain to eye)
    d. Toxic/Nutritional
    e. Trauma
  4. Previously Edematous
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19
Q

What is a way you can tell if the Pt has Papilledema vs. B/L Disc Edema?

A
  1. In Disc Edema, ACUITY will be DECREASED!
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20
Q

AAION

  1. Cause of AAION?
  2. Major Symptoms?
  3. Test for Dx?
  4. **Elevated ESR for Men
  5. Elevated ESR for Women
A
  1. Occlusion of SHORT POSTERIOR CILIARY ARTERIES
  2. SUDDEN vision loss in ONE EYE w/other symptoms (HA, Malaise, Jaw claudication, etc…)
  3. Increased ESR and CRP, also increased Platelets; TABs.
  4. Age/2
  5. (age +10)/2
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21
Q

NAION

  1. What is it?
  2. Usually seen in whom?
  3. Risk Factors?
  4. Symptoms?
  5. VF Loss.
  6. Tests (Sedimentation rate, CRP, Platelet count)
A
  1. Ischemia to Anterior part of Optic Disc.
  2. > 50 y/o; M=F
  3. HTN, DM, Hypercholesterolemia, Disc at risk (Small disc…not cause, but is a RISK)
  4. sudden, painless, irreversible, non-progressive vision loss in 1 eye, usually noticed after waking up.
  5. Varies, but MOST COMMON: Inferior Altitudinal Defect
  6. All NORMAL, and no systemic symptoms.
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22
Q
  1. Define DIABETIC PAPILLOPATHY
A
  1. Type of NAION WITHOUT VISION LOSS in a Pt w/Diabetes.
23
Q

OPTIC NEURITIS

  1. What is it?
  2. Usually seen in whom?
  3. Symptoms?
  4. Signs?
  5. After ACUTE EPISODE: What tends to happen?
  6. Associated w/what Dz?
A
  1. Primary inflammation of the ON
  2. Age: 20-45; Females > Males
  3. U/L sudden vision loss (VA: 20/20 to NLP), PAIN ON EYE MOVEMENT is seen in 90%
  4. 2/3: Retrobulbar Optic Neuritis w/NORMAL APPEARING ON. 1/3: Papillitis w/Disc Edema. BOTH HAVE APD!
  5. Vision usually Returns to NORMAL w/DECREASED CONTRAST SENSITIVITY and OPTIC NERVE PALLOR
  6. MS! (56% of cases) *MS can also have an INO (MLF lesion)
24
Q

Neuroretinitis

  1. What kind of Optic Neuritis is it?
    a. What is SEEN with it on the RETINA?
    b. Type of Dz: Infectious or Non-infectious; Immune or non Immune-mediated?
    c. Causes (3)
A
  1. Anterior
    a. STELLATE MACULAR STAR (cause: Optic Disc Vasculopathy and leakage into the Macula)

b. Infectious and Immune-Mediated
c. Cat Scratch Dz, Histoplasmosis and Toxoplasmosis

25
Q

Papillophlebitis

  1. Who is it seen in?
  2. Vision?
  3. Systemic Dzs associated?
  4. What does it look like?
A
  1. Young, healthy peeps
  2. Good
  3. None
  4. Looks like a CRVO in a young, healthy person.
26
Q

Thyroid-Related Ophthalmology (Graves’ Ophthalmology)

  1. Type of Dz?
  2. Characterized by what 3 things?
  3. Signs: Multiple…list some.
  4. Which RECTI are usually affected FIRST?
A
  1. AI
  2. Edema of the EOMs, Orbital Adipose tissue prolapse, and ON Compression.
  3. UPPER EYELID RETRACTION, EXOPHTHALMOS, Disc Edema, APD, Decreased acuity and color vision, VF Defects
  4. INFERIOR and MEDIAL RECTI.
    (I think it goes: I, M, S, L)….LOOK THIS UP!
27
Q

Malignant (SEVERE) Hypertension

  1. What is it?
A
  1. Papilledema due to HBP: >220/>120. ER.
28
Q

Foster Kennedy Syndrome

  1. Rare condition due to what?
  2. Causes what to occur?
A
  1. FRONTAL LOBE TUMOR
  2. Disc Edema in one eye; Disc Pallor w/Decreased Vision in the OTHER EYE.
    * May also have POOR SACCADIC FUNCTION towards the Swollen Nerve Side
29
Q

Pseudotumor Cerebri

  1. Who?
  2. Signs/Symptoms?
  3. Diagnosis of Exclusion: What do we test to see if this is the case?
  4. Some things that could cause it (CANT)
A
  1. Fat Fertile Myrtle
  2. Papilledema, ENLARGED BLIND SPOT ON VFs. CN 6 Palsy, HAs.
  3. Normal MRI, Normal CSF content, BUT, HIGH OPENING PRESSURE on LP (>200 mm water)
  4. Contraceptives, Vitamin A, Naladixic Acid, Tetracyclines
30
Q

Toxic/Nutritional Optic Neuropathy

  1. What is the CLASSIC Sign seen?
  2. Symptoms?
  3. CAUSES?
A
  1. TEMPORAL PALLOR of the Optic Nerves
  2. B/L, Painless, Progressive Vision Loss and CENTRAL or CENTROCECAL VF LOSS
  3. Alcoholism, Malnutrition, Tobacco Abuse, Toxicity from MEDS!
31
Q

Papilledema: Tests

  1. HTN:
  2. Tumor
  3. Brains/Veins
  4. What else?
A
  1. BP
  2. MRI
  3. MRV
  4. LP
32
Q

Leber’s Hereditary Optic Neuropathy

  1. Cause?
  2. Get this from whom?
  3. Affects mostly whom?
  4. Onset?
  5. MAIN CHARACTERIZED SYMPTOM?
  6. Early Signs?
  7. Late Signs?
A
  1. Mitochondrial DNA Mutations
  2. MOTHER
  3. Mostly MALES (85%)
  4. Late Teens/Early 20s
  5. Sudden DECREASED CENTRAL VISION (20/200 to CF)
  6. Disc Hyperemia
  7. Optic Disc Atrophy
33
Q

Dominant Optic Atrophy

  1. Most common type of what?
  2. When does it develop?
  3. CHARACTERIZED BY WHAT SYMPTOM?; What Signs?
A
  1. Hereditary Optic Atrophy
  2. YOUNG (childhood)
  3. Insidious Onset of Mild to Moderate Visual Loss (20/30-20/70);
    * Temporal PALLOR and EXCAVATION (Optic Nerves)
34
Q

Congenital Anomalies: Optic Nerve Pit

  1. What is it?
  2. Main Location?
  3. Pt is at RISK for what?
  4. Symptoms?
A
  1. U/L Depression of Optic Disc
  2. Inferior/Temporal
  3. SEROUS RD
  4. Asymptomatic, unless Macula is involved
35
Q

Congenital Anomalies: Morning Glory Syndrome

  1. Uni/Bi?
  2. Characterized by what 3 things?
  3. What symptom is seen?
A
  1. U/L
  2. Enlarged, Funnel-Shaped, Excavated ON
  3. Poor VAs
36
Q

Congenital Anomalies: Optic Nerve Hypoplasia

  1. Uni/Bi
  2. What is it?
  3. Major SIGN?
  4. Symptoms?
  5. Associated with what 2 maternal issues?
A
  1. Either
  2. Optic Nerve doesn’t completely form
  3. DOUBLE RING SIGN (Disc is Hypoplastic w/a Ring of Sclera and a Ring of Hyperpigmentation)
  4. Mild to Severe Vision Loss
  5. FAS and Maternal Drug Use
37
Q

Congenital Anomalies: Optic Nerve Coloboma

  1. What is it?
  2. Cause?
  3. Usual Location
  4. What other defects do Pts have?
A
  1. a Large, abnormal shaped Disc
  2. Incomplete closure of the Embryonic Fissure
  3. INFERIOR/NASAL
  4. Systemic Defects
38
Q

Congenital Anomalies: Optic Nerve Head Drusen

  1. What is it?
  2. They Appear HYPER-REFLECTIVE on what test?
A
  1. HYALINE BODIES in Optic Disc. We start seeing them more as we AGE. Can cause VF Defects
  2. on B-SCAN
39
Q

Optic Nerve Tumors

  1. Melanocytoma
    a. What is it? (Benign/Malignant; Pigmented/Non-pigmented)
    b. More common in whom?
  2. Optic Nerve Sheath Meningioma
    a. Benign/Malignant?
    b. Uni/Bi?
    c. Seen more in whom?
    d. What happens to the ON?
  3. Optic Nerve Glioma
    a. Benign/Malignant?
    b. Can be associated with what Dz?
A
  1. a. Benign, Darkly Pigmented tumor. Adjacent to or on TOP of the Optic Nerve.
    b. AAs
    * DOES NOT AFFECT VISION
  2. a. Benign mostly
    b. U/L
    c. Young-Middle Aged women
    d. Starts Edematous, then leads to SECONDARY OPTIC ATROPHY and Progressive Vision Loss
  3. a. Benign if starts in CHILDHOOD; MALIGNANT if starts in ADULTHOOD.
    b. Neurofibromatosis
40
Q
  1. Explain REVERSE APD
A
  1. Good Eye: Pupil will CONSTRICT on APD testing. Good to know when Bad Eye has a Corneal Opacity, traumatic pupil, etc…
41
Q
  1. Anisocoria: % that is physiological?
A
  1. 20%
42
Q

Aniso: Pupil Size

  1. 3 Dzs where the ABNORMAL Pupil will be SMALLER in the DARK? (Miotic pupil: larger difference b/w the 2 eyes in the dark)
  2. 4 Times when the ABNORMAL Pupil will be LARGER in the LIGHT (Abnormal Pupil is Miotic: Larger difference b/w the pupil size in the light)
A
  1. Horners, Itis, AR

2. 80s (0.125% pilo), CN3 (1% pilo), Trauma, Pharmacological

43
Q

Aniso: Adie’s Tonic Pupil

  1. What is it?
  2. What causes it?
  3. Seen mostly in whom?
  4. U/L or B/L?
  5. The iris has what kind of MOVEMENT?
  6. Will pupil constrict to light?
  7. Will pupil constrict to near object?
  8. What % of Pilocarpine will cause a Pupil constriction due to HYPERSENSITIVITY of the Cholinergic Receptors on the Iris Sphincter Muscle?
  9. ADie’s Pupil = ?
A
  1. Acute Dilated pupil.
  2. Lesion in the CILIARY GANGLION or Ciliary nerves
  3. Young (20-40) FEMALES (30-70%)
  4. U/L…then becomes B/L at a rate of 4%/yr.
  5. VERMIFORM MOVEMENT (seen in SLE)
  6. Slow and minimal to no constriction in response to light
  7. Slow Constriction to a near object.
  8. 0.125%
  9. Acute Dilated pupil due to a CG lesion.
44
Q

Aniso: Argyll Robertson Pupil

  1. MIOTIC Pupil associated with what 3 dzs?
  2. Due to a LESION in what?
  3. U/L or B/L?
  4. Characterized by what?
  5. How does it respond to light?
  6. How does the pupil respond to near objects?
    a. Why is this?
  7. Argyll Robertson Pupil…=?
A
  1. NEUROSYPHILIS, Diabetes, Alcoholism
  2. in the TECTOTEGMENTAL TRACT (Pretectal Nuclei to I/L and C/L EW Nuclei)
  3. U/L…then becomes B/L w/time
  4. LIGHT-NEAR DISSOCIATION
  5. little to no constriction to light.
  6. Constricts Normally to convergence/accommodation
    a. this is mediated by FRONTAL EYE FIELDS that send input to EW nuclei.
  7. Accommodative Response Present
45
Q

Aniso: Horner’s Syndrome

  1. Miotic Pupil most notable in dim illumination due to a LESION where?
  2. What TRIAD do patient’s present with?
  3. Cocaine Test: Horners: Dilates or not?
    a. What does this tell us?
  4. Hydroxyamphetamine: 1%: normally dilates normal EYES. What kind of lesion do we think of when it does not dilate Horner’s pupil?
  5. 1% APRACLONIDINE: What will it do in Horner’s?
A
  1. Sympathetic pathway… (Pancoast Tumor at apex of lung)
  2. Miosis, Anhydrosis (no sweating), and Ptosis on the affected side.
  3. NO DILATION (normal eyes: dilates eyes by blocking re-uptake of norepi)
    a. Helps us decide if it’s pre or postganglionic lesion
  4. POSTGANGLIONIC LESION suspected
  5. PUPIL DILATION (Adrenergic Receptors on Iris Dilator muscle are HYPERSENSITIVE)
46
Q

Coma Pupils: Hutchinson’s Pupil

  1. What is it?
  2. Due to what?
A
  1. U/L Dilated pupil in a comatose Pt

2. Ipsilateral Tumor or Subdural Hematoma compressing on Pupillary Fibers on surface of CN 3!

47
Q

Coma Pupils: Miosis

  1. Why does early stages of coma induce Miosis?
A
  1. Inhibitory Cortical Input to the EW nucleus is ABSENT. Put they still respond to LIGHT!
48
Q

CN 3:

  1. Superior Division innervates what?
  2. Inferior Division innervates what?
  3. What will a Complete CN 3 Palsy look like?
  4. Symptoms
  5. Etiology
  6. Pupil Involvement in what kind of lesion?
    a. No pupil involvement in what kind of lesion?
  7. If the pupil is involved or the Pt has an INCOMPLETE CN 3 Palsy, what test should be done!?
A
  1. Levator and SR
  2. IR, MR, IO; Parasympathetic Fibers travel with it to Ciliary Muscle and Iris Sphincter Muscle
  3. Down and Out and Ipsilateral Ptosis (is that right???)
  4. could have diplopia
  5. Microvascular Infarct, Trauma and Aneurysm (LOOK THIS INFO UP!)
  6. Compressive (tumor/Aneurysm): FIXED and DILATED
    a. Ischemic Palsy
  7. MRI/CT and MRA to r/o Aneurysm (most commonly at the POSTERIOR COMMUNICATING ARTERY!)
49
Q

CN 4: Trochlear

  1. CN4 Palsy presents w/what type of Deviation?
  2. Symptoms
  3. Etiology
  4. Congenital will have what? (vs. Acquired)
  5. Dx?
A
  1. HYPERDEVIATION w/a Torsional Component.
  2. VERTICAL DIPLOPIA; maybe torsional Diplopia; HEAD TILT AWAY from SIDE of LESION to MINIMIZE diplopia
  3. Trauma/Congenital. *Most susceptible to Trauma due to longest course in the body of all the CNs.
  4. Congenital: LARGE VERTICAL VERGENCE RANGES
  5. Park’s 3 Step; Double Maddox rod for Torsional
50
Q

CN 6: Abducens Nerve

  1. *Most common of the 3 CN Palsies affecting EOMs. Symptom?
  2. Etiology?
  3. Differential Dx?
A
  1. Horizontal Diplopia
  2. Microvascular Infarction; Pseudotumor cerebri, Trauma, Tumor, Horner’s Syndrome
  3. Duane’s Syndrome and Infantile or Accommodative Esotropia
51
Q

EOM Palsy: Most common causes

  1. CN3
  2. CN4
  3. CN6
  4. What kind of cause will usually resolve w/in 3 Months?
A
  1. Aneurysm
  2. Trauma, Congenital
  3. Increased ICP
  4. Microvascular
52
Q

What 2 DZs should ALWAYS be considered for ALL ocular motor palsies?

A
  1. MG and TED
53
Q

Ocular Myasthenia

  1. What is this?
    a. 90% of Pts w/Systemic MG will have what?
  2. What is going on here?
  3. Symptoms?
  4. Dx?
A
  1. MG in the eye. Involves the muscles of the eye.
    a. ocular signs at some point; 70% of cases will have ocular signs as the initial sign of MG.
  2. Ach receptors are blocked or altered at the NMJ, causing weakness of skeletal muscles
  3. Levator and EOMs are susceptible to a deficiency in innervation causing Ptosis and Diplopia. Signs vary and are worse at the end of the day or when the patient is tired.
  4. Tensilon test or high serum levels of Ach Receptor Antibodies. *Injected IV. Inhibits breakdown of Ach in Synaptic cleft, prolonging its duration of action. (tensilon uses Edrophonium)