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Flashcards in Neuro VIII Deck (76):
1

What happens with CN V motor lesion?

Jaw deviates TOWARD side of lesion due to unopposed opposite pterygoid

2

What happens with CN X lesion?

1) uvula deviates AWAY from side of lesion (SCM)
(Weak side collapses and uvula points away).

3

What happens with CN XII lesion?

Tongue deviates TOWARD side of lesion ("lick your wounds") due to weakened tongue muscles on affected side.

4

What happens with facial nerve UMN lesion?

Contralateral paralysis of lower muscles of facial expression, sparing forehead due to bilateral UMN innervation

5

Presentation of facial nerve LMN lesion?

1) ipsilateral paralysis of upper and lower muscles of facial expression.
2) hyperacusis + loss of taste sensation to anterior tongue.

6

most common facial nerve palsy?

Idiopathic (aka Bell palsy)

7

other causes of facial nerve palsy?

1) lyme disease
2) HSV
3) herpes zoster (Ramsay hunt syndrome)
4) sarcoidosis
5) tumors
6) DM

8

path of venous drainage from eye and superficial cortex

eye and superficial cortex --> cavernous sinus --> internal jugular vein.

9

Cavernous sinus syndrome presentation

1) Variable ophthalmoplegia
2) decreased corneal sensation 3) Horner syndrome
4) occasional deceased maxillary sensation

10

CN most susceptible to injury with cavernous sinus syndrome

CN VI

11

Causes of cavernous sinus syndrome

1) mass effect from tumor
2) carotid-cavernous fistula
3) cavernous sinus thrombosis related to infection

12

tonotopy concept

Each frequency of vibration of hair cells leads to vibration at specific location on basilar membrane.

13

Where are frequencies heard in cochlea?

1) Low frequency heard at apex near helicotrema (wide and flexible).
2) High frequency heard base at base of cochlea (thin and rigid).

14

Rinne test findings with conductive hearing loss

Abnormal (bone greater than air)

15

Rinne test findings with sensorineural hearing loss

Normal (air greater than bone)

16

weber test results

Localizes to affected ear with conductive, and normal ear with sensorineural.

17

How do sudden extremely loud noises produce hearing loss?

Due to tympanic membrane rupture.

18

Where do cholesteatomas occur?

middle ear

19

What is a cholesteatoma?

overgrowth of desquamated keratin debris

20

Sequela of cholesteatoma?

Can erode ossicles and mastoid air cells causing conductive hearing loss.

21

Inner to outer layers of eye

Retina --> choroid --> sclera

22

what inhibits aqueous humor production?

1) beta blockers
2) A2 agonists
3) carbonic anhydrase inhibitors

23

Receptors on Iris dilator muscle?

alpha2

24

Receptors on iris sphincter muscle?

M3

25

Aqueous humor pathway

produced in ciliary body --> flows through posterior chamber up and over lens --> flows above iris --> then flows through trabecular meshwork and into canal of scheme and into episcleral vasculature (90% OR drains into urea and sclera (uveoscleral outflow)

26

With do M3 agonists affect?

trabecular outflow.

27

What do prostaglandin agonists affect?

Uveoscleral outflow

28

Hyperopia pathophys

Eye too short for refractive power of cornea and lens --> light focused behind retina.

29

Myopia pathophys

Eye too long for refractive power of cornea and lens --> light focused in front of retina.

30

astigmatism etiology and sequela

Abnormal curvature of cornea leading to different refractive power at different axes.

31

What is presbyopia caused by?

Decreased lens elasticity

32

cataracts?

painless, often bilateral opacification of lens.

33

cataracts RFs

1) age
2) smoking
3) excessive alcohol use
4) excessive sunlight
5) chronic corticosteroid use
6) DM
7) trauma
8) infection

34

congenital RFs for cataracts

1) classic galactosemia
2) galactokinase deficiency
3) trisomies 13,18,21
4) rubella
5) Marfan
6) Alport syndrome
7) myotonic dystrophy
8) NF2

35

Glaucoma etiology?

Optic disc atrophy with cupping + elevated IOP usually

36

visual manifestation of glaucoma?

Progressive peripheral visual field loss

37

What is cupping?

Thinning of outer rim of optic nerve head.

38

open-angle glaucoma RF's

1) increased age
2) AA race
3) family history

39

Which glaucoma type is more common in US?

open-angle

40

Cause of secondary open-angle glaucoma

1) blocked trabecular meshwork from WBCs (uveitis), RBCs (vitreous hemorrhage), retinal elements (retinal detachment).

41

primary closed angle glaucoma pathophys

Enlargement or forward movement of lens against central iris (pupil margin) leads to obstruction of normal aqueous flow through pupil --> fluid builds up behind iris, pushing peripheral iris against cornea and impeding flow through trabecular meshwork.

42

Secodnary closed angle glaucoma pathophys

Hypoxia from retinal disease induces vasoproliferation in iris that contracts angle.

43

causes of secondary closed angle glaucoma

1) DM
2) vein occlusion

44

chronic closed angle closure glaucoma pathophys

often asymptomatic with damage to optic nerve and peripheral vision.

45

acute closure glaucoma pathophys

Increased IOP pushes iris forward --> angle closes abruptly.

46

acute closure glaucoma presentation

very painful, red eye, sudden vision loss + halos around light + rock-hard eye + frontal headache

47

Drug contraindicated with acute closure glaucoma

epinephrine (mydriatic effect)

48

How to differentiate allergic, bacterial, viral conjunctivitis?

Allergic --> itchy eyes and bilateral
Bacterial --> pus
Viral --> sparse mucous discharge, swollen pre auricular node.

49

most common cause of conjunctivitis?

viral (adenovirus)

50

anterior uveitis

iritis

51

intermediate uveitis

pars planitis inflammation

52

posterior uveitis

choroidits and/or retinitis

53

other findings in uveitis

1) hypopyon
2) conjunctival redness

54

hypopyon

accumulation of pus in anterior chamber

55

Uveitis associations

*systemic inflammatory disorders
1) sarcoidosis
2) RA
3) JRA
4) HLA-B27 associations

56

Visual effects of macular degeneration?

1) metamorphopsia
2) loss of central vision (scotomas)

57

metamorphopsia

distortion of vision

58

dry mac degeneration prophylaxis

multivitamin + antioxidants

59

more common type of macular degeneration?

Dry (over 80%)

60

where does drusen deposit with macular degeneration?

In and between Bruch membrane and retinal pigment epithelium.

61

difference in presentation between wet and dry macular degeneration?

Dry presents with gradual loss vision; wet with rapid loss of vision

62

cause of wet macular degeneration?

Bleeding secondary to choroidal neovascularization.

63

wet macular degeneration treatment

ranibizumab

64

non proliferative diabetic retinopathy pathophys..

Damaged capillaries leak blood --> lipids and fluid seep into retina --> hemorrhages and macular edema occur.

65

treatment for non proliferative diabetic retinopathy pathophys..

blood sugar control

66

proliferative diabetic retinopathy pathophys..

Chronic hypoxia results in new blood vessel formation with resultant traction on retina.

67

proliferative diabetic retinopathy treatment

1) peripheral retinal photocoagulation
2) surgery
3) anti-VEGF

68

Retinal vein occlusion pathophys

Blockage of central or branch retinal vein due to compression from nearby arterial atherosclerosis.

69

Retinal vein occlusion presentation on fundoscopy

Retinal hemorrhage and venous engorgment. Edema in affected area.

70

retinal detachment pathophys

Separation of neurosensory layer of retina (photoreceptor layer with rods and cones) from outermost pigmented epithelium --> degeneration of photoreceptors --> vision loss.

71

normal function of pigmented retinal epithelium

Shields retina from excess light and supports retina.

72

Causes of retinal detachment

1) retinal breaks
2) diabetic traction
3) inflammatory effusions

73

fundoscopy findings with retinal detachment?

1) Crinkling of retinal tissue
2) changes in vessel direction

74

Rss for retinal detachment

1) high myopia
2) history of head trauma

75

retinal detachment presentation

1) often preceded by posterior vitreous detachment (flashes and floaters)
2) eventual monocular vision loss like curtain drawn down.

76

CN XI lesion

1) Weakness turning head to contralateral side of lesion (SCM). Shoulder droop on side of lesion (trapezius).
2) Left SCM contracts to help turn the head to the right.