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Flashcards in Principles in Neurology_2 Deck (350):
1

how does hydrocephalus ex vacuo look on imaging?

apparent increase in CSF observed on imaging is actually result of ↓ neural tissue due to neuronal atrophy

2

what type of hydrocephalus is obstructive?

noncommunicating hydrocephalus

3

noncommunicating hydrocephalus is caused by what?

a structural blockage of CSF circulation within the ventricular system (e.g. stenosis of the aqueduct of Sylvius)

4

how many spinal nerves are there?

31 spinal nerves: • 8 cervical • 12 thoracic • 5 lumbar • 5 sacral • 1 coccygeal

5

Nerves C1-C7 exit where?

above the corresponding vertebrae

6

all nerves other than C1-C7 exit where?

below the corresponding vertebrae

7

what happens in vertebral disc herniation?

nucleus pulposus (soft central disc) herniates through anulus fibrosus (outer ring)

8

vertebral disc herniation usually occurs where?

posterolaterally at L4-L5 or L5-S1

9

in adults, spinal cord extends to where?

lower border of L1-L2 vertebrae

10

in adults, subarachnoid space extends to where?

lower border of S2

11

lumbar puncture is usually performed at what level?

between L3-L4 or L4-L5 (level of cauda equina)

12

how do you obtain sample of CSF without damaging spinal cord?

to keep the cord alive, keep the spinal needle between L3 and L5

13

what info is carried by the dorsal columns?

pressure, vibration, touch, proprioception

14

the dorsal columns comprise which structures?

Fasciculus cuneatus • Fasciculus gracilis

15

fasciculus cuneatus conveys what info?

pressure, vibration, touch, proprioception from the upper body, extremities

16

fasciculus gracilis conveys what info?

pressure, vibration, touch, proprioception from the lower body, extremities

17

lateral spinothalamic tract conveys what info?

pain, temperature

18

anterior spinothalamic tract conveys what info?

crude touch , pressure

19

lateral corticospinal tract conveys what info?

voluntary motor

20

intermediate horn sympathetics emerge at what levels?

T1-L2/L3

21

what is important to remember as a general rule about spinal tract anatomy and functions?

ascending tracts synapse then cross

22

the dorsal column contributes to which tract?

medial lemniscal pathway

23

what is the function of the medial lemniscal pathway of the dorsal column?

ascending pressure, vibration, fine touch, and propioception

24

what is the 1st order neuron in the doral column medial lemniscal pathway?

sensory nerve ending→ cell body in dorsal root ganglion→ enters spinal cord, ascends ipsilaterally in dorsal column

25

what is synapse I of the dorsal column medial lemniscal pathway?

ipsilateral nucleus cuneatus or gracilis (medulla)

26

what is the 2nd order neuron in the dorsal column medial lemniscal pathway?

decussates in medulla →ascends contralaterally in medial lemniscus

27

where is synapse 2 in the dorsal column medial lemniscal pathway?

VPL (thalamus)

28

where is the 3rd order neuron in the dorsal column medial lemniscal pathway?

sensory cortex

29

what is the function of the lateral spinothalamic tract?

pain, temperature

30

what is the function of the anterior spinothalamic tract?

crude touch, pressure

31

where is the 1st order neuron in the spinothalamic tract?

sensory nerve ending (Aδ and C fibers) (cell body in dorsal root ganglion)→enters spinal cord

32

where is synapse 1 in the spinothalamic tract?

ipsilateral gray matter (spinal cord)

33

where is the 2nd order neuron in the spinal thalamic tract?

decussates at anterior white commissure →ascends contralaterally

34

where is synapse 2 in the spinothalamic tract?

VPL (thalamus)

35

where is the 3rd order neuron in the spinothalamic tract?

sensory cortex

36

what is the function of the lateral corticospinal tract?

descending voluntary movement of contralateral limbs

37

where is the 1st order neuron in the lateral corticospinal tract?

UMN: cell body in 1° motor cortex→descends ipsilaterally (through internal capsule) until decussating at caudal medulla (pyramidal decussation)→descends contralaterally

38

where is synapse 1 in the lateral corticospinal tract?

cell body of anterior horn (spinal cord)

39

what is the 2nd order neuron in lateral corticospinal tract?

LMN: leaves spinal cord

40

where is synapse 2 in the lateral corticospinal tract?

NMJ

41

when do you see weakness in motor neuron lesion?

UMN + • LMN+

42

when do you see atrophy in motor neuron lesion?

UMN - • LMN +

43

when do you see fasciculations in motor neuron lesion?

UMN - • LMN +

44

how do reflexes present in motor neuron lesion?

UMN ↑ • LMN ↓

45

how does tone present in motor neuron lesion?

UMN ↑ • LMN ↓

46

when do you see Babinski sign in motor neuron lesion?

UMN + • LMN -

47

when do you see spastic paralysis in motor neuron lesion?

UMN + • LMN -

48

when do you see flaccid paralysis in motor neuron lesion?

UMN - • LMN +

49

when do you see clasp knife spasticity in motor neuron lesion?

UMN + • LMN -

50

what do you see in lower motor neuron lesion?

everything lowered (less muscle mass, ↓ muscle tone, ↓ reflexes, down going toes)

51

what do you see in upper motor neuron lesion?

everything up (tone, DTR, toes)

52

What is the area of the spinal cord affected in poliomyelitis and Werdnig-Hoffman disease?

IMAGE pg 429

53

what are the characteristics of spinal cord lesions in poliomyelitis and Werdnig-Hoffman disease?

LMN lesions only, due to destruction of anterior horns; flaccid paralysis

54

what area of the spinal cord is affected by Multiple Sclerosis?

IMAGE pg 429

55

what are the characteristics of the spinal cord lesions in multiple sclerosis?

mostly white matter of cervical region; random and asymmetric lesions, due to demyelination; scanning speech, intention tremor, nystagmus

56

what areas of the spinal cord are affected in ALS?

IMAGE pg 429

57

what are the characteristics of spinal cord lesions in ALS?

combined UMN and LMN deficits with no sensory, cognitive, or oculomotor deficits; both UMN and LMN signs

58

ALS can be caused by what?

defect in superoxide dismutase I

59

ALS commonly presents as what?

fasciculations with eventual atrophy; progressive and fatal

60

what is the treatment for ALS?

Riluzole treatment modestly ↑ survival by ↓ presynaptic glutamate release

61

what area of the spinal cord is affected by complete occlusion of the anterior spinal artery?

IMAGE pg 429

62

what are the characteristics of spinal cord lesions caused by complete occlusion of the ASA?

spares dorsal columns and Lissauer's tract

63

which territory of ASA is a watershed area?

upper thoracic territory is a watershed area, as artery of Adamkiewicz supplies ASA below T8

64

what area of the spinal cord is affected by tabes dorsalis?

IMAGE pg 429

65

tabes dorsalis is caused by what?

3° syphilis

66

tabes dorsalis results from what?

degeneration (demyelination) of dorsal columns and roots

67

tabes dorsalis causes what?

impaired sensation and propioception and progressive sensory ataxia (inability to sense or feel the legs)

68

tabes dorsalis is associated with what?

Charcot's joints • shooting pain • Argyll robertson pupil

69

what is Argyll robertson pupil?

small bilateral pupils that further constrict to accommodation but not to light

70

in tabes dorsalis, exam will demonstrate what?

absence of DTRs and positive Romberg

71

what area of the spinal cord is affected in syringomyelia?

IMAGE pg 429

72

what are the characteristics of the spinal cord lesion in syringomyelia?

syrinx expands and damages anterior white commissure of spinothalamic tract (2nd-order neurons) → bilateral loss of pain and temperature temperature sensation (usually C8-T1)

73

syringomyelia is seen with what?

Chiari I malformation

74

what area of the spine is affected by Vitamin B12 or Vitamin E deficiency?

IMAGE pg 429

75

what are the characteristics of the spinal lesion in Vitamin B12/E deficiencies?

subacute combined degeneration- demyelination of dorsal columns, lateral corticospinal tracts, and spinocerebellar tracts

76

what are the symptoms caused by spinal cord lesions in VitB12/VitE deficiency?

ataxic gait • paresthesia • impaired position and vibration sense

77

poliomyelitis is caused by what?

poliovirus

78

what is the transmission of poliovirus?

fecal-oral transmission

79

poliovirus replicates where?

in the oropharynx and small intestine

80

how does poliovirus spread after replication in the oropharynx and small intestine?

by blood to CNS

81

poliovirus infection causes what?

destruction of cells in anterior horn of spinal cord (LMN death)

82

what are the LMN lesion signs of poliomyelitis?

weakness, hypotonia, flaccid paralysis, atrophy, fasciculations, hyporeflexia, and muscle atrophy

83

what are the signs of infection of poliomyelitis?

malaise, HA, fever, nausea

84

what are the findings in poliomyelitis?

CSF with ↑WBC with slight elevation of protein, no Δ in CSF glucose. virus recovered from stool or throat

85

what is Werdnig-Hoffman disease?

Congenital degeneration of anterior horns of spinal cord → LMN lesion

86

what is the typical presentation of Werdnig-Hoffman syndrome?

'floppy baby' with marked hypotonia and tongue fasciculations

87

what is the prognosis for Werdnig-Hoffman syndrome?

infantile type has median age of death of 7 months

88

what is the inheritance of Werdnig-Hoffman syndrome?

autosomal recessive inheritance

89

what is Friedreich's ataxia?

Autosomal-recessive trinucleotide repeat disorder (GAA) in gene that encodes frataxin

90

Friedreich's ataxia leads to impairment in what?

mitochondrial functioning

91

what are the symptoms of Friedreich's ataxia?

staggering gait • frequent falling • nystagmus • dysarthria • pes cavus • hammer toes • hypertrophic cardiomyopathy (cause of death)

92

Friedreich's ataxia presents how?

in childhood with kyphoscoliosis

93

what is Brown-Sequard syndrome?

Hemisection of the spinal cord

94

what are the findings in Brown-Sequard syndrome?

1. Ipsilateral UMN signs below the level of the lesion • 2. Ipsilateral loss of tactile, vibration and propioception sense below the lesion • 3. contralateral pain and temperature loss below the level of the lesion • 4. Ipsilateral LMN signs at the level of the lesion

95

why are there ipsilateral UMN signs below the level of the lesion in Brown-Sequard?

due to corticospinal tract damage

96

why is there ipsilateral loss of tactile, vibration, propioception sense below the level of the lesion in Brown-Sequard syndrome?

dorsal column damage

97

why is there contralateral pain and temperature loss below the level of the lesion in Brown-Sequard syndrome?

spinothalamic tract damage

98

what happens in Brown-Sequard syndrome if the lesion occurs above T1?

patient may present with Horner's syndrome due to damage of sympathetic ganglion

99

What causes Horner's syndrome?

sympathectomy of face

100

what are the symptoms of Horner's syndrome?

Ptosis • Anhydrosis • Miosis

101

Horner's syndrome is associated with which conditions?

spinal cord lesion above T1: • Pancoast tumor • Brown-Sequard syndrome • late-stage syringomyelia

102

The 3-neuron oculosympathetic pathway pojects from where?

hypothalamus to the intermediolateral column of the spinal cord, then to the superior cervical (sympathetic) ganlgion, and finally to the pupil, the smooth muscle of the eyelids, and the sweat glands of the forehead and face

103

interruption of which pathway causes horner's syndrome?

3-neuron oculosympathetic pathway

104

what is the sensory distribution of the C2 dermatome?

posterior half of a skull cap

105

what is the sensory distribution of the C3 dermatome?

high turtleneck shirt

106

what is the sensory distribution of the C4 dermatome?

low-collar shirt

107

what is the sensory distribution of the T4 dermatome?

at the nipple

108

what is the sensory distribution of the T7 dermatome?

at the xiphoid process

109

what is the sensory distribution of the T10 dermatome?

at the umbilicus

110

why is the T10 dermatome important?

early appendicitis pain referral

111

what is the sensory distribution of the L1 dermatome?

at the inguinal ligament

112

what is the sensory distribution of the L4 dermatome?

includes the Kneecaps

113

what is the sensory distribution of the S2,S3,S4 dermatomes?

erection and sensation of penile and anal zones

114

diaphragm and gallbladder pain referred to the right shoulder via what?

phrenic nerve

115

biceps reflex = which nerve root?

C5

116

Triceps reflex = which nerve root?

C7

117

Patella reflex = which nerve root?

L4

118

Achilles reflex = which nerve root?

S1

119

what is the Babinski sign?

dorsiflexion of the big toe and fanning of other toes

120

Babinski reflex is a sign of what?

UMN lesion, but normal in 1st year of life

121

what defines primitive reflexes?

CNS reflexes that are present in a healthy infant, but are absent in a neurologically intact adult

122

when do primitive reflexes normally disappear?

within 1st year of life

123

primitive reflexes are inhibited by what?

a mature/developing frontal lobe

124

when can primitive reflexes reemerge in adults?

following frontal lobe lesions →loss f inhibition

125

what is the Moro reflex?

hang on for life reflex- abduct extend limbs when startled, and then draw together

126

what is the rooting reflex?

movement of head toward one side if cheek or mouth is stroked (nipple seeking)

127

what is the sucking reflex?

sucking response when roof of mouth is touched

128

what is the palmar reflex?

curling of fingers if pam is stroked

129

what is the plantar reflex?

dorsiflexion of large toe and fanning of other toes with plantar stimulation

130

what is the Galant reflex?

stroking along one side of the spine while newborn is in ventral suspension causes lateral flexion of lower body toward the stimulated side

131

which cranial nerves lie medially at the brainstem?

III, VI, XII • Motor=Medial

132

what is the function of the pineal gland?

melatonin secretion, circadian rhythms

133

what is the function of the superior colliculi?

conjugate vertical gaze center

134

what is the function of the inferior colliculi?

auditory

135

what is Parinaud syndrome?

paralysis of conjugate vertical gaze due to lesion in superior colliculi (e.g. pinealoma)

136

what is CNI?

olfactory nerve

137

what is the function of the olfactory nerve?

smell

138

CNI is the onlt CN without what?

thalamic relay to cortex

139

what is CNII?

optic

140

what is the function of CNII?

sight

141

what is CNIII?

oculomotor nerve

142

what is the function of CNIII?

eye movement (SR, IR, MR, IO), pupillary constriction, accommodation, eyelid opening (levator palpebrae)

143

what is the pathway used by CNIII to affect pupillary constriction?

sphincter pupillae: Edinger-Westphal nucleus, muscarinic receptors

144

what is CNIV?

trochlear nerve

145

what is the function of CNIV?

eye movement (SO)

146

what is CNV?

trigeminal nerve

147

what is the function of CNV?

mastication, facial sensation, somatosensation from the anterior 2/3 of the tongue

148

what are the divisions of facial sensation by branches of CNV?

ophthalmic • maxillary, • mandibular

149

what is CNVI?

abducens nerve

150

what is the function of abducens nerve?

eye movement (LR)

151

what is CNVII?

Facial nerve

152

what is the function of CNVII?

facial movement • taste from anterior 2/3 of tongue • lacrimation • salivation (submandibular and sublingual glands) • eyelid closing (orbicularis oculi) • stapedius muscle in ear

153

which nerve crosses through the parotid gland but does not innervate it

facial

154

what is CNVIII?

vestibulocochlear

155

what is the function of CNVIII?

hearing, balance

156

what is CNIX?

glossopharyngeal nerve

157

what is the function of CNIX?

taste and somatosensation from posterior 1/3 of tongue • swallowing • salivation (parotid gland) • monitoring carotid body and sinus chemo and baroreceptors • stylopharyngeous (elevates pharynx and larynx)

158

what is CNX?

Vagus

159

what is the function of CNX?

Taste from epiglottic region • swallowing • palate elevation • midline uvula • talking • coughing • thoracoabdiminal viscera • monitoring aortic arch chemo and baroreceptors

160

what is CNXI?

spinal accessory nerve

161

what is the function of the spinal accessory nerve?

head turning, shoulder shrugging (SCM, trapezius)

162

what is CNXII?

hypoglossal nerve

163

what is the function of CNXII?

tongue movement

164

CNI is what type?

sensory

165

CNII is what type?

Sensory

166

CNIII is what type?

motor

167

CNIV is what type?

motor

168

CNV is what type?

Both

169

CNVI is what type?

motor

170

CNVII is what type?

both

171

CNVIII is what type?

sensory

172

CNIX is what type?

both

173

CNX is what type?

both

174

CNXI is what type?

motor

175

CNXII is what type?

motor

176

where are cranial nerve nuclei located?

tegmentum portion of brain stem between dorsal and ventral portions

177

Midbrain contains the nuclei of which cranial nerves?

CN III • CN IV

178

pons contains the nuclei of which cranial nerves?

CN V, VI, VII, VIII

179

medulla contains the nuclei of which cranial nerves?

CN IX, X, XII

180

spinal cord contains the nuclei of which cranial nerves?

XI

181

Lateral nuclei=

Sensory (aLar plate)

182

Medial Nuclei=

motor (basal plate)

183

what separates the medial and lateral cranial nerve nuclei

sulcus limitans

184

what is the afferent branch of the Corneal reflex?

V1 ophthalmic (nasociliary branch)

185

what is the efferent branch of the corneal reflex?

VII (temporal branch; orbicularis oculi)

186

what is the afferent branch of the lacrimation reflex?

V1 (loss of reflex does not preclude emotional tears)

187

what is the efferent branch of the lacrimation reflex?

VII

188

what is the afferent branch of the jaw jerk reflex?

V3 (sensory- muscle spindle from masseter)

189

what is the efferent branch of the jaw jerk reflex?

V3 (motor- masseter)

190

what is the afferent branch of the pupillary reflex?

CNII

191

what is the efferent branch of the pupillary reflex?

CNIII

192

what is the afferent branch of the gag reflex?

CNIX

193

what is the efferent branch of the gag reflex?

CNX

194

what are the 3 vagal nuclei?

Nucleus Solitarius • Nucleus aMbiguus • Dorsal motor nucleus

195

function of nucleus solitarius?

Visceral Sensory information (taste, baroreceptors, gut distention)

196

which CN synapse on neurons in the nucleus solitarius?

VII • IX • X

197

function of nucleus ambiguus?

Motor innervation of pharynx, larynx, and upper esophagus (swallowing, palate, elevation)

198

which CN synapse on neurons in the Nucleus Ambiguus?

IX • X

199

function of the motor nucleus?

sends autonomic (parasympathetic) fibers to heart, lungs, and upper GI

200

which CN synapse on dorsal motor nucleus?

X

201

CN I traverses what pathway?

Cribriform plate

202

which cranial nerves traverse the middle cranial fossa through the sphenoid bone?

CN II-VI

203

which structures traverse the optic canal?

CNII • ophthalmic artery • central retinal vein

204

which structures traverse the superior orbital fissure?

CN III, IV, V1, VI, ophthalmic vein, sympathetic fibers

205

which structures traverse the foramen rotundum?

CNV2

206

which structures traverse the foramen ovale?

CNV3

207

which structures traverse the foramen spinosum?

middle meningeal artery

208

Which cranial nerves traverse the posterior cranial fossa through the temporal or occipital bone?

CN VII- XII

209

which cranial nerves traverse the internal auditory meatus?

CNVII, VIII

210

which structures traverse the jugular foramen?

CNIX, X, XI jugular vein

211

which structures traverse the hypoglossal canal?

CNXII

212

which structures traverse the foramen magnum?

spinal roots of CN XI, brain stem, vertebral arteries

213

what is the cavernous sinus?

a collection of venous sinuses on either side of the pituitary

214

which drainage pathway goes through the cavernous sinus?

blood from the eye and superficial cortex → cavernous sinus → internal jugular vein

215

which structures pass through the cavernous sinus?

CNIII, IV, V1, V2 and VI and postganglionic sympathetic fibers en route to the orbit • + cavernous portion of internal carotid artery

216

what can cause cavernous sinus syndrome?

mass effect, fistula, thrombosis

217

what are the clinical features of cavernous sinus syndrome?

ophthalmoplegia and ↓ corneal and maxillary sensation with normal vision

218

what is the clinical presentation of a CN V motor lesion?

Jaw deviates toward side of lesion due to unopposed force from opposite pterygoid muscle

219

what is the common clinical presentation of a CN X lesion?

Uvula deviates away from side of lesion. Weak side collapses and uvula points away

220

what is the clinical presentation of a CN XI lesion?

weakness turning head to contralateral side of lesion. shoulder droop on side of lesion • left SCM contracts to help turn head to the right

221

what is the clinical presentation of a CN XII (LMN) lesion?

tongue deviates toward side of lesion (lick your wounds) due to weakened tongue muscles on the affected side

222

what are the diagnostic features of conductive hearing loss?

Rinne test= abnormal (bone > air) • Weber= localizes to affected ear

223

what are the diagnostic features of sensorineural hearing loss?

Rinne= normal (air>bone) • Weber= localizes to unaffected ear

224

sudden extreme loud noises can produce hearing loss due to what?

tympanic membrane rupture

225

what causes noise induced hearing loss that begins with high frequency hearing loss?

damage to stereociliated cells in organ of corti

226

what is the cause of an UMN facial lesion?

lesion of motor cortex or connection between cortex and facial nucleus

227

what are the symptoms of UMN facial lesions?

contralateral paralysis of lower face; forehead spared due to bilateral UMN innervation

228

what are the symptoms of LMN facial lesions?

Ipsilateral paralysis of upper and lower face

229

what causes facial nerve palsy?

complete destruction of the facial nucleus itself or its branchial efferent fibers (facial nerve proper)

230

what are the symptoms of facial nerve palsy?

peripheral ipsilateral facial paralysis with inability to close eye on involved side

231

what is the prognosis for idiopathic facial nerve palsy?

gradual recovery in most cases

232

facial nerve palsy is seen as a complication in what?

AIDS • lyme disease • herpes simplex • [less common] herpes zoster • sarcoidosis • tumors • diabetes

233

what is idiopathic facial nerve palsy called?

Bell's palsy

234

what 3 muscles close the jaw?

Masseter • teMporalis • Medial pterygoid • M's Munch

235

what is the muscle that opens the jaw?

Lateral pterygoid • Lateral Lowers

236

the muscles of mastication are innervated by what?

CN V3

237

the ciliary body comprises which structures?

ciliary muscle • ciliary process

238

what are the fluid filled spaces in the anterior segment of the eye?

anterior chamber • posterior chamber

239

what is the fluid filled space in the posterior segment of the eye?

vitreous chamber

240

refractive errors are characterized by what?

impaired vision that improves with glasses

241

what happens in hyperopia?

eye too short for refractive power of cornea and lens → light focused behind retina

242

what happens in myopia?

eye to long for refractive power of cornea and lens → light focused in front of the retina

243

what happens in astigmatism?

abnormal curvature of cornea resulting in different refractive power at different axes

244

what happens in accommodation?

focusing on near objects → ciliary muscles tighten → zonular fibers relax → lens becomes more convex

245

accommodation occurs with what?

convergence and miosis

246

what happens in presbyopia?

↓ change in focusing ability during accommodation due to sclerosis and decreased elasticity

247

what is uveitis?

inflammation of the uveal coat

248

uveal coat consists of what?

iris, ciliary body, choroid

249

uveitis is often associated with what?

systemic inflammatory disorder: • sarcoid • RA • juvenile idiopathic arthritis • TB • HLA-B27

250

what is retinitis?

retinal edema and necrosis leading to scar

251

cause of retinitis is often what?

viral: • CMV • HSV • HZV

252

retinitis is associated with what?

immunosuppression

253

clinical features of central retinal artery occlusion?

acute, painless monocular vision loss • retina whitening with cherry red spot

254

function of the canal of Schlemm?

collects aqueous humor from trabecular meshwork

255

function of trabecular meshwork?

collects aqueous humor that flows through anterior chamber

256

function of ciliary epithelium?

produces aqueous humor

257

receptor type on ciliary muscle?

M

258

receptor type on Ciliary epithelium?

β

259

receptor type on eye sphincter?

M3

260

receptor type on eye dilator muscle?

α1

261

glaucoma is characterized by what?

optic neuropathy, usually with ↑ intraocular pressure • painless

262

open/wide angle glaucoma is characterized by what?

peripheral then central vision loss usually with ↑ IOP; • optic disc atrophy with cupping

263

open/wide angle glaucoma is associated with what?

↑age • African American • family Hx • ↑IOP

264

open angle glaucoma is more common where?

USA

265

what causes open angle glaucoma?

1° cause unclear • 2° causes: • uveitis • trauma • corticosteroids • vasoproliferative retinopathy that can block or ↓ outflow at the trabecular meshwork

266

what happens in closed/narrow angle glaucoma?

enlargement or forward movement of lens against central iris leads to obstruction of normal aqueous flow through pupil → fluid builds up behind iris, pushing peripheral iris against cornea and impeding flow through the trabecular meshwork

267

features of closed angle glaucoma with chronic closure?

often asymptomatic with damage to optic nerve and peripheral vision

268

which type of glaucoma is an ophthalmic emergency?

closed angle with acute closure

269

what happens in closed angle glaucoma with acute closure?

↑ IOP pushes iris forward → angle closes abruptly

270

clinical features of closed angle glaucoma with acute closure?

very painful • sudden vision loss • halos around lights • rock hard eye • frontal headache

271

what is contraindicated in the treatment of closed angle glaucoma with acute closure?

epinephrine because of its mydriatic effect

272

what are cataracts?

painless, often bilateral, opacification of lens → ↓ in vision

273

what are the risk factors for cataracts?

age • smoking • EtOH • excessive sunlight • prolonged corticosteroid use • classic galactosemia • galactokinase deficiency • diabetes (sorbitol) • trauma • infection

274

what is papilledema?

optic disc swelling (usually bilateral) due to ↑ ICP (2° to mass effect)

275

fundoscopic findings in papilledema?

enlarged blind spot and elevated optic disc with blurred margins

276

which cranial nerves innervate extraocular muscles?

CN VI → Lateral Rectus • CN IV → Superior Oblique • CN III → the rest • LR6SO4R3

277

action of superior oblique muscle?

abducts, intorts, and depresses while adducted

278

what happens in CNIII damage?

eye looks down and out; ptosis, pupillary dilation, loss of accommodation

279

what happens in CN IV damage?

eye moves upward, particularly with contralateral gaze and ipsilateral head tilt • (problems going down stairs)

280

what happens in CN VI damage?

medially directed eye that cannot abduct

281

how do you test Superior rectus?

look up and out (temporal)

282

how do you test lateral rectus?

look straight out to the side (temporal)

283

how do you test inferior rectus?

look down and out

284

how do you test superior oblique?

look down and in

285

how do you test medial rectus?

look straight in (nasal)

286

how do you test inferior oblique?

look up and in

287

what is pupillary miosis?

constriction, parasympathetic

288

what are the neurons in the control of miosis?

1st: Edinger-Westphal nucleus to ciliary ganglion via CN III • 2nd: short ciliary nerves to pupillary sphincter muscles

289

what is mydriasis?

dilation, sympathetic

290

what are the neurons in the control of mydriasis?

1st: hypothalamus to ciliospinal center of Budge (C8-T2) • 2nd: exit at T1 to superior cervical ganglion (travels along cervical sympathetic chain near lung apex, subclavian vessels) • 3rd: plexus along internal carotid, through cavernous sinus; enters as long ciliary nerve to pupillary dilator muscle

291

what is the circuit activated in the pupillary light reflex?

light in either retina sends a signal via CN II to pretectal nuclei in midbrain that activate bilateral Edinger-Westphal nuclei; pupils contract bilaterally

292

what is the result of the pupillary light reflex?

illumination of 1 eye results in bilateral pupillary constriction

293

what is Marcus Gunn pupil?

afferent pupillary defect ( due to optic nerve damage or retinal detachment)

294

findings in Marcus Gunn pupil?

↓ bilateral pupillary constriction when light is shone in affected eye relative to unaffected eye

295

what are the 2 components of CN III?

motor = central • parasympathetic = peripheral

296

center of CNIII does what?

motor output to ocular muscles

297

center of CNIII is affected primarily by what?

vascular disease: • ↓diffusion of oxygen and nutrients to the interior fibers from compromised vasculature that resides on outside of nerve

298

signs of center of CNIII compromise?

ptosis + down and out gaze

299

peripheral fibers of CNIII are first affected by what?

compression: • posterior communicating artery aneurysm • uncal herniation

300

what are the signs of compression of peripheral fibers of CN III?

diminished or absent pupillary light reflex • "blown pupil"

301

what happens in retinal detachment?

separation of neurosensory layer of retina (photoreceptor layer with rods and cones) from outermost pigmented epithelium (normally shields excess light, supports retina)→degeneration of photoreceptors → vision loss

302

retinal detachment may be due to what?

retinal breaks • diabetic traction • inflammatory effusion

303

retinal breaks are more common in whom?

pts w/ high myopia

304

retinal breaks are often preceded by what?

posterior vitreous detachment (flashes and floaters) and eventual monocular vision loss "curtain drawn down"

305

which cause of retinal detachment presents as a surgical emergency?

retinal break

306

what is age-related macular degeneration?

degeneration of central area of retina

307

age related macular degeneration causes what?

distortion (metamorphopsia) and eventual loss of central vision (scotomas)

308

what is the more common subtype of age related macular degeneration?

dry, nonexudative >80%

309

dry ARMD is characterized by what?

deposition of yellowish extracellular material beneath retinal pigment epithelium ("drusen") with gradual ↓ in vision

310

prevent progression of dry ARMD with what?

multivitamin and antioxidant supplements

311

what is the less common subtype of ARMD?

wet, exudative 10-15%

312

wet ARMD is characterized by what?

rapid loss of vision due to bleeding secondary to choroidal neovascularization

313

what is the treatment for wet ARMD?

anti-VEGF injections or laser

314

what causes unilateral anopia?

cut optic nerve

315

what cause bitemporal hemianopia?

lesion of optic chiasm

316

what causes homonymous hemianopia?

lesion of optic tract

317

what causes left upper quadrantic anopia?

right temporal lesion (meyers loop) • MCA

318

what causes left lower quadrantic anopia?

right parietal lesion (dorsal optic radiation) • MCA

319

what causes homonymous hemianopia with macular sparing?

PCA infarct

320

what causes central scotoma?

macular degeneration

321

path of meyers loop?

inferior retina; loops around inferior horn of lateral ventricle

322

path of dorsal optic radiation?

superior retina; takes shortest path via internal capsule

323

what is the medial longitudinal fasciculus?

pair of tracts that allows for crosstalk between CN VI and CNIII nuclei

324

MLF coordinates what?

both eyes to move in same horizontal direction

325

how much myelin in MLF?

highly myelinated

326

MLF lesions seen in which patients?

demyelination: MS

327

lesion in MLF causes what?

INO= internuclear ophthalmoplegia

328

what happens in INO?

lack of communication such that when CNVI nucleus activates ipsilateral lateral rectus, contralateral CN III nucleus does not stimulate medial rectus to fire

329

what happens to abducting eye in INO?

nystagmus (CN VI overfires to stimulate CN III)

330

how is convergence in INO?

normal

331

what is dementia?

↓ in cognitive ability, memory, or function with intact consciousness

332

What are the causes of dementia?

AD • Pick's disease • Lewy body dementia • CJD • Multi-infarct • Syphilis • HIV • Vit B1/B3/B12 deficiency • NPH

333

what is the most common cause of dementia in the elderly?

Alzheimer's disease

334

what is the second most common cause of dementia in the elderly?

Multi-infarct

335

who has an ↑ risk of developing Alzheimer's?

Down syndrome patients

336

what is the frequency of familial form Alzheimer's?

10%

337

Early onset Alzheimer's is associated with which proteins on which chromosomes?

APP (21) • presenilin-1 (14) • presenilin-2 (1)

338

late onset familial Alzheimers is associated with which protein on which chromosome?

ApoE4 (19)

339

which protein on which chromosome is protective against Alzheimer's?

ApoE2 (19)

340

what are the histologic/gross findings in AD?

1. Widespread cortical atrophy • 2. ↓ ACh • 3. Senile plaques • 4. Neurofibrillary tangles

341

What are the features of senile plaques in AD?

extracellular β-amyloid core • may cause amyloid angiopathy → intracranial hemorrhage

342

how is Aβ synthesized?

cleaving amyloid precursor protein

343

features of neurofibrillary tangles in AD?

intracellular, abnormally phosphorylated tau protein= insoluble cytoskeletal elements

344

tangles in AD correlate with what?

degree of dementia

345

clinical presentation of Pick's disease?

dementia, aphasia, parkinsonian aspects; • change in personality

346

what structures are spared in Pick's disease?

parietal lobe and posterior 2/3 of superior temporal gyrus

347

other name for Pick's disease?

frontotemporal dementia

348

histologic/gross findings in Pick's disease?

Pick Bodies: spherical tau protein aggregates • Frontotemporal atrophy

349

clinical features of Lewy body dementia?

Parkinsonism with dementia and hallucinations

350

histologic/gross findings in Lewy body dementia?

α-synuclein defect