Pathoma CNS Flashcards
(134 cards)
0
Q
What’s anencephaly? How would the mom present?
A
Cranial neural tube defect. Fetal absence of skull and brain. Frog like appearance.
Mom: polyhydramnios and ⬆️ AFP
1
Q
What are neural tube defects associated with and how are they detected in prenatal care?
A
Low folate levels prior to conception
⬆️ AFP in amniotic fluid and maternal blood
2
Q
What’s spins bifida? What are the 3 ways it can present?
A
Caudal neural tube defect of posterior vertebral arch closure
- Meningocele: cystic protrusion of meninges thru defect
- meningomyelocele: cystic protrusion of meninges and spinal cord thru defect
- Spins bifida occulta: dimple or hair patch overlying defect
3
Q
What embryo structures from the CNS, ventricles/spinal cord canal and PNS?
A
CNS: wall of neural tube
Ventricles and spinal cord canal: Lumen of neural tube
PNS: neural crest cells
4
Q
What’s the most common cause of hydrocephalus in newborns?
A
Cerebral aqueduct stenosis
5
Q
What’s cerebral aqueduct stenosis?
A
Congenital stenosis of cerebral aqueduct (drains 3rd ventricle into 4th) ➡️ hydrocephalus & enlarged head circumference
6
Q
What’s the flow of CSF in the brain?
A
CSF is produced by choroid plexus ➡️ lateral ventricles ➡️ foramen of monro ➡️ 3rd ventricle ➡️ cerebral aqueduct ➡️ 4th ventricle ➡️ foramen of luschka (2 lateral) and Magendie (1 middle) ➡️ subarachnoid space
7
Q
What’s Dandy-walker malformation?
Features?
A
Congenital failure of cerebellar vermis (separates cerebellar halves) to form
Newborn: enlarged 4th ventricle/ posterior fossa, no cerebellum, hydrocephalus
8
Q
What’s Arnold-Chiari Malformation? Features?
A
Congenital downward displacement of cerebellar vermis and tonsils thru foramen magnum
Newborn: hydrocephalus; occurs with meningomyelocele and syringmyelia
9
Q
What tract carried pain and temperature?
A
Spinothalamic tract (part of anteriolareral tract)
10
Q
What does the Spinothalamic tract transport and where are the neurons located?
A
sPinoThalamic: pain and temperature
1st order neuron: peripheral nerve to posterior horn, cell body in dorsal root ganglion
2nd order neuron: arises from post horn, immediately crosses over anterior what commissure & ascends to thalamus
3rd order neuron: thalamus to cortex
11
Q
What does the dorsal column/medial lemniscus transport and where are the neurons?
A
PPTV- pressure, proprioception, touch, vibration
1st order neurons: peripheral nerves to medulla via dorsal column. Cell body in dorsal root ganglion
2nd order neurons: at medulla, crosses over, ascends via medial lemniscus to thalamus
3rd order: thalamus to cortex
12
Q
What does that lateral corticospinal tract transport and where are the neurons?
A
Voluntary movement
1st order: cortex pyramidal neurons descend, cross over in medulla pyramids & synapse on anterior motor horn of spinal cord (upper motor neuron)
2nd order: anterior motor horn & synapses on muscle (lower motor neuron)
13
Q
What does the hypothalamospinal tract transport and where are the neurons?
A
Sympathetic face input
1st order: from hypothalamus, synapse on T1 lateral horn
2nd order: T1 lateral horn to superior cervical ganglion
3rd order: SVG to eyelids, pupil and face skin
14
Q
What path runs through the anterior horn of the spinal cord?
A
lateral corticospinal tract (voluntary movement)
15
Q
What’s syringomyelia? Where does it usually occur? What’s it associated w/ and what’s lost?
A
cystic degeneration of the spinal cord (usually at C8-T1 - upper extremities) assoc w/ trauma or Arnold-Chiari malformation
Lost: sensory loss of pain and temperature (spinothalamic tract in the anterior white commissure) in the upper extremities (“Cape-like distribution”)
16
Q
In syringomyelia what senses are lost vs what’s spared and why?
A
Lost senses: Pain and temperature b/c lesion is in spinothalamic tract’s anterior white commissure
Spared senses: pressure, proprioception, touch and vibration) b/c part of dorsal column
17
Q
If syringomyelia expands, what other spinal tracts can become involved and how would they present?
A
- Anterior horn lateral corticospinal tract: muscle atrophy and weakness w/ decreased muscle tone and reflexes (damaged lower motor neurons)
- Lateral horn hypothalamospinal tract at T1: horner’s syndrome (interrupted sympathetic input to the face)
18
Q
what’s poliomyelitis and how does it present?
A
poliovirus infection damages anterior motor horn of spinal column.
Presents w/ lower motor neuron signs (decrease in everything): flaccid paralysis w/ muscle atrophy, fasciulations, weakness, impaired reflexes & negative Babinski sign (downgoing toes)
19
Q
What’s Werdnig-Hoffman Disease?
How does it present?
A
AR degeneration of anterior motor horn
Floppy baby w/ death w/in few yrs
20
Q
What’s ALS? How do the 2 degeneration locations present?
A
ALS - Amyotrophic Lateral Sclerosis
Degenerative disorder of upper and lower motor neurons of the corticospinal tract
1. Anterior horn degeneration: lower motor neuron signs (decreased everything)
2. Lateral corticospinal tract degeneration: upper motor neuron signs (everything’s increased - spastic paralysis w/ hyperreflexia, increased muscle tone & positive Babinski)
21
Q
What’s an early sign of ALS? Who gets ALS?
A
Early sign: atrophy & weakness of hands (no sensory loss)
Most ALS is sporadic in middle-aged adults. Familial mutation: Zinc-copper SOD1 mutation (normally converts superoxide to hydrogen peroxide): free radical injury to neurons
22
Q
What’s Friedreich Ataxia, what causes it and what are some symptoms?
A
AR disorder from expanded unstable trinucleotide GAA repeat in Frataxin gene leads to degeneration of cerebellum (leads to ataxia) and spinal cord (leads to loss of vibration, proprioception, lower extremity muscle weakness and loss of reflexes)
23
Q
What’s the function of Frataxin gene. When does Friedreich ataxia present and what’s it associated with?
A
Frataxin gene is essential for mitochondrial iron regulation, loss leads to iron buildup w/ free radical damage to cerebellum and spinal cord
Presents in early childhood, wheelchair bound w/in few years
Associated w/ hypertrophic cardiomyopathy
24
What's meningitis? How does it present?
inflammation of the leptomeninges (pia & arachnoid)
Presents w/ classic triad: headache, nuchal rigidity and fever. May also present w/ photophobia (MC w/ viral infection), vomiting and altered mental status
25
What's the MC causes of meningitis in neonates, nonvaccinated infants, kids/teens, and adults/elderly?
Neonates: "GEL" Group B Strep, E. coli & Listeria monocytogenes (from birthing process)
Nonvaccinated infants: H. influenza
Kids/teens: N. menigitidis (thru nares)
Adults/Elderly: Strep pneumoniae
26
How do yo diagnose meningitis? How do you differentiate the causitive agents?
CSF via lumbar puncture btwn L4 & L5 (iliac crest level)
Bacterial meningitis: neutrophils w/ decreased CSF glucose (bacteria consume glucose). Gram stain & culture for organism
Viral meningitis: lymphocytes w/ norm CSF glucose (norm CSF glucose = 2/3 serum glucose)
Fungal meningitis: lymphocytes w/ decreased glucose (fungi consume glucose)
27
What type of meningitis are complications seen w/ and what types?
Bacterial meningitis
Death due to herniation from cerebral edema
Hydrocephalus, hearing loss and seizures related to fibrosis
28
At what level does the spinal cord, subarachnoid space and cauda equina end?
spinal cord: L2
| subarachnoid space and cauda equina: S2
29
What layers need to be crossed during a lumbar puncture?
"Shiny LEDs Are Sexy"
Skin, Ligaments, epidural space, dura, arachnoid, subarachoind space (where CSF is)
PIA IS NOT PIERCED
30
what are the 2 major categories/causes of cerebrovascular disease?
1. Ischemia (85%)
| 2. Hemorrhage (15%)
31
what are the 2 major categories of both ischemic and hemorrhagic cerebrovascular diseases?
```
Ischemic:
1. Global Cerebral Ischemia (GCI)
2. Focal: Ischemic stroke (symptoms > 24 hrs) or Transient ischemic attach (TIA, symptoms < 24 hrs)
Hemorrhagic:
1. Intracerebral hemorrhage
2. subarachnoid hemorrhage
```
32
what are major causes of global cerebral ischemia and examples of each?
1. low perfusion - ex atherosclerosis
2. acute decrease in blood flow - ex cardiogenic shock
3. chronic hypoxia - ex anemia
4. repeat episodes of hypoglycemia - ex insulinoma
33
what are clinical features and a example of mild global ischemia?
Mild global ischemia - transient confusion w/ prompt recovery. ex: insulinoma, low glucose, pt confused, give glucose feels better
34
what are clinical features and an example of severe global ischemia?
severe global ischemia: results in diffused necrosis; survival leads to a vegetiative state
35
what's clinical features and an example of moderate global ischemia?
moderate global ischemia: leads to infarcts in watershed areas (regions fed by end of circulation) and damage to highly vulnerable regions
Ex: area lying btwn regions fed by anterior and middle cerebral artery
36
what regions are highly vulnerable to moderate global ischemia? what would each lead to?
1. Pyramidal neurons of cerebral cortex (layers 3, 5 & 6): leads to laminar (lines of) necrosis
2. Pyramidal neurons of hippocampus in the temporal lobe: leads to long term memory loss
3. Purkinje layer of the cerebellum: loss of integration of sensory perception w/ motor control
37
what'st the function of the hippocampus and where is it located?
transports information to long term memory
| location: temporal lobes
38
what's an ischemic stroke? what are the 3 subtypes?
focal regional ischemia to the brain that results in focal neuro deficits lasting > 24 hrs
1. thrombotic stroke
2. embolic stroke
3. Lacunar strokes
39
what's a thrombotic stroke, where does it usually occur and what does it result in?
Ischemic stroke due to ruptured atherosclerotic plaque (exposed eubepithelial collagen develops thrombus w/ necrotic debris
Usually occurs at branch points (ex: bifurcation of ICA & MCA in circle of willis)
Results in a pale infarct at periphery of cortex
40
what's a embolic stroke, where does it usually occur and what does it result in?
Ischemic stroke due to thromboemboli, usu from L heart (a-fib)
Usu occurs in middle cerebral a (MCA)
Results in hemorrhagic infarct bc thromboemboli is eventually lysed at periphery of cortex
41
what's a lacunar stroke, where does it usually occur and what does it result in?
ischemic stroke secondary to hyaline arteriolosclerosis (thick vessels w/ small lumen), a complication of HTN or DM
Usu occurs in lenticulostriate vessels off MCA
Results in small cystic areas of infarction, affecting deep structures of the brain
42
if a pt suffers from a lacunar stroke involving the internal capsule or thalamus, how would they present?
Internal capsule involvement: pure motor stroke
| Thalamus involvement: pure sensory stroke
43
what are the pathology stages seen in an ischemic stroke?
1. Early (12 hrs post infarct): red neurons w/ eosinophilic changes in cytoplasm
2. 24 hrs: necrosis
3. 1-3 days: neutrophil infiltration
4. 4-7 days: microglial cells infiltration (brain macrophages)
5. 2-3 weeks: gliosis: reactive atrocytes line the fluid filled cystic space --> liquifactive necrosis
44
what kind of infarct is seem w/ a thrombotic stroke, embolic stroke and lacunar stroke?
Thrombotic stroke: pale infarct
embolic stroke: hemorrhagic infarct
Lacunar stroke: small cystic infarcts in deep brain structures
45
what's an intracerebral hemorrhage and what usually causes it?
bleeding into brain parenchyma
Usu due to Charcot-Bouchard microaneurysms (complications of HTN weakens bv wall) of the lenticulostriate vessels. Basal ganglia is MC site
46
how does an intracerebral hemorrhage present?
severe headache, nauseau, vomiting and eventually coma. often a complication of HTN which leads to Charcot-Bouchard microaneurysms
47
what's a subarachnoid hemorrhage and what usually causes it?
| what's a major complication of it?
bleeding into the subarachnoid space (bleed on brain bottom)
Usu due to ruptured berry aneurysm (medial layer of bv fails to form) from trauma. Also caused by AV malformations and anticoagulated states
Major complication is vasospam a few days layer leading to death
48
how does a subarachnoid hemorrhage present?
"worst headache of my life" w/ nuchal rigidity
49
how do you diagnose a subarachnoid hemorrhage?
lumbar punction shows xanthochromia: yellow CSF due to bilirubin breakdown)
"worse headache of my life"
50
what are berry aneurysms? where are they most likely to form and what are they associated with?
thin-walled saccular outpouching that lacks a media layer of the bv, increasing rupture risk leading to subarachnoid hemorrhage
Usu in anterior circle of willis at branch pts of anterior communicating artery
Assoc w/ Marfan Syndrome & AD polycystic kidney disease
51
what's an epidural hematoma? what causes it, how does it present on CT?
Collection of blood btwn dura and skull usu due to fracture of temporal bone (trauma) w/ rupture of Middle Meningeal A.
Lens shaped lesion: bleeding separates dura from skull
52
how would a pt w/ an epidural hematoma present? what's a lethal complication?
post-trauma (possibly fractured temporal bone)
Lucid internal may precede neuro signs: feels fine, then gets sleep. Ipsilaterally blown pupil & ipsilateral paresis
Lethal complication: herniation a few days later
53
what's a subdural hematoma? What casuses it and how does it present on CT?
Collection of blood under dura, covers brain surface.
Due to tearing bridging veins (in subdural space), usu from trauma
Crescent-shaped lesion: b/c subdural space is a real space
54
how would a pt w/ a subdural hematoma present? Who does it happen to frequently and what's a lethal complication?
Presents w/ progressive neruological signs post trauma
increased occurrence in elderly due to cerebral atrophy which stretches the veins
Herniation: lethal complication
55
what's a brain herniation?
displacement of brain tissue due to mass effect or increased intracranial pressure
56
what's a tonsillar herniation? what can it lead to?
displacement of cerebellar tonsils into the foramen magnum
| Can compress the brain stem leading to cardiopulmonary arrest
57
what's a subfalcine (cingulate) herniation? what can it lead to?
displaced cingulate gyrus under falx cererbri
| Can compress the Anterior Cerebral A leading to infarction
58
what's a uncal herniation? what can it compress?
displaced medial temporal lobe uncus under tenrorium cerebelli ( btwn cerebellum & brainstem)
Can compress:
1. CN III: eyes down & out, ipsilateral ptosis & dilated
2. Posterior Cerebral A: infarcts occipital lobe (contralateral homonymous hemianopsia)
3. Rupture Paramedian A ➡️Duret (brainstem) hemorrhage. Caudal displacement of brain stem
4. Contralateral crus cerebri (Kernohan's notch): ipsilateral paresis
59
what's the function of myelin and what produces it in the CNS and PNS?
Insulates axons, improving speed and conduction
Oligodendrocytes myelinate in CNS
Schwann cells myelinate PNS
60
what are leukodystrophies?
Inherited mutations in enzymes needed for production or maintenance of myelin (demyelinating disorder)
61
what's metachromatic leukodystrophy?
MC leukodystrophy
AR lysosomal storage disease w/ deficiency of arylsulfatase A, sulfatides build up in oligodendrocytes lysosomes, destroying myelin
62
What's Krabbe disease?
Leukodystrophy due to AR deficiency of galactocerebrosidase where galactocerebroside accumulates in macrophages
63
What's adrenoluekodystrophy?
X-linked defect due to impaired addition of coA to long-chain fatty acids. Fatty acids accumulate and damage adrenal glands and brain's white matter.
64
What is Multiple Sclerosis? Who's it usually seen in?
Autoimmune destruction of CNS myelin and oligodendrocytes
MC chronic CNS disease of young adults (20-30s); MC in women
Assoc w/ HLA-DR2 & regions away from the equator
65
how does multiple sclerosis present? Common clnical features?
Relapsing neuro deficits w/ periods of remission (multiple lesions in time & space)
Blurred vision in 1 eye (CN II)
vertigo & scanning speech mimicking intoxication (brainstem)
internuclear ophthalplegia (Medial longitudinal fasiculus)
Hemiparesis or hemisensory loss (cerebral white matter or spinal cord)
bowel, bladder and sexual dysfunction (ANS)
66
How do you diagnose MS? (3 things)
1. MRI: periventricular plaques - areas of white matter demyelination
2. Lumbar puncture: ⬆️ lymphocytes & protein (IgG) oligoclonal IgG bands on electrophoresis & myeline basic protein
3. Gross exam: gray plaques in white matter
67
what's the treatment of acute attacks and long-term for MS? Neurogenic bladder, spasticity or pain?
Acute attacks: high-dose steroids
Long-term: Interferon beta - slows disease progression; immunosupression, Natalizumab
Neurogenic bladder: muscarinic antagonists or catheter
Spasticity: Baclofen, GABA receptor agonist
Pain: opioids
68
what's the medial longitudinal fasciculus?
connects contralateral CNs VI (lateral rectus) & CN III (medial rectus) to contract when looking to one side, ipsilateral lateral rectus contracts (via CN VI) & contralateral medial rectus contracts (via MLF connecting CN VIto contralateral CN III)
69
what happens in internuclear ophthalmoplegia?
Medial Longitudinal Fasciculus damage, leads to disorder of lateral conjugate gaze, impaired adduction.
When attempt to look contralateral to affected eye, affected eye adducts minimally & contralateral eye abducts w/ nystagmus
Leads to horizontal diplopia
70
what's Subacute Sclerosing Panechephalitis?What causes it?
demyelinating disorder of progressive, debilitating encephalitis that leads to death
SSP: SSlow progressive Persistent infection"
Cause: slowly progressing, persistent infection of the brain by measles virus. Infection in infancy & neuro signs years later (childhood)
71
what's the pathology of Subacute Sclerosising Panenchephalitis?
viral inclusions w/in neurons (gray matter) & ologiodendrocytes (white matter)
72
What's Progressive Multifocal Leukoencephalopathy? How does it present?
```
JC virus (latent) infection of oligodendrocytes (white matter) reactivated in immunospuressed (AIDs, leukemia)
rapidly Progressive neuro signs: visual loss, weakness, dementia, leading to death
```
73
What's Central Pontine Myelinolysis? What causes it and how does it present?
Focal demyelination of the pons (anterior center brain stem)
Due to rapid intravenous correction of hyponatremia in malnourished (alcoholics; liver dx)
Presents as acute bilateral paralysis: "locked in syndrome"
74
What are the major causes of the following demylinating disorders:
1. Leukodystrophies
2. Multiple Sclerosis
3. Subacute Sclerosis Panecephalitis
4. Progressive Multifocal Leukoencephalopathy
5. Central Pontine Myelinolysis
1. Leukodystrophies: inherited enzyme defects
2. Multiple Sclerosis: Autoimmune; assoc w/ HLA-DR2
3. Subacute Sclerosis Panencephalitis: Measles virus (slowing progressing, persistent infection)
4. Progressive Multifocal Leukoencephalopathy: JC virus
5. Central Pontine Myelinolysis: Rapid IV correction of hyponatremia
75
What is dementia characterized by?
Loss of neurons within the gray matter
| Often due to accumulation of protein which damages neurons
76
what does degeneration of the gray matter cortex vs brainstem and basal ganglia lead to?
Cortex: dementia
| Brainstem & basal ganglia: movement disorders
77
what's the MC of dementia?
Alzheimer Disease
78
what's Alzheimer Disease and who gets it (normally and early and late onset familial forms)?
degenerative disease of the cortex (cortical atrophy)
95% sporadic in elderly
Early onset AD:
1. Familial: assoc w/ Presenilin 1 (chrom 14) & 2 (chrom 1) mutations. Also APP genes (chrom 21)
2. Down Syndrome: common by 40 yrs (APP is on chrom 21)
Late onset AD:
Chrom ApoE4 (chrom 19)
79
What alleles of apoliporotein E (APOE) are associated w/ an increased and decreased risk of Alzheimer Disease?
What chromosome are they one?
Increased risk: E4 allele of APOE; increased conversion of APP to AB amyloid form
Decreased risk: E2 allele of APOE
Both on chrom 19
80
Describe the cleavage of Amyloid Precursor Protein (APP) and how it can leave to Alzheimer Disease
APP is a transmembrane neuron receptor.
alpha-secretase cleaves it to alpha-amyloid (normal)
Beta-secretase cleaves it to AB-amyloid which builds up in extracellular entangled neuritic plaques
81
Why is Alzheimer Disease assoc with Down Syndrome?
APP (amyloid precursor protein) is on chrom 21
82
What are some clinical features of a patient with Alzheimer Disease?
slow- onset memory loss (1st short term, progresses to long-term memory loss) & progressive disorientation
Loss of learned motor skills & language
Change in behavior and personality
Pt becomes mute & bedridden
83
what's a common cause of death in an Alzheimer Disease pt?
infection
84
What are 4 morphological features seen in Alzheimer Disease?
1. Cerebral atrophy: narrowed gyri, widened sulci & dilated ventricles (hydrocephalus ex vacuo)
2. Neuritic plaques: extracellular AB amyloid w/ entangled neuritic processes
3. Neurofibrillary tangles: intracellular fiber aggregates of hyperphosphorylated tau protein (microtubule-assoc)
4. Loss of cholinergic neurons in Nucleus Basalis of Meynert (⬇️ACh)
85
What's vascular dementia?
multifocal infarction & injury due to HTN, atherosclerosis or vasculitis. Consequence of moderate global cerebral ischemia
2nd MC causes of dementia
86
What's Pick Disease?
Degenerative dx of the frontal & temporal cortex
| "the disease "picks" the frontal & temporal"
87
What's the characteristic finding in Pick Disease? How does it present?
Pick Bodies: round aggregates of tau protein in cortex neurons
Behavioral (frontal) & language (temporal) symptoms early; progresses to dementia
88
What's Parkinson Disease?
Degenerative loss of dopaminergic neurons in the substantia niagra of the basal ganglia needed for nigrostriatal pathway to initiate movement
89
what causes Parkinson Disease?
unkonwn etiology but rare causes related to MPTP exposure
90
What are clinical features of Parkinson Disease?
"TRAP"
Tremor - pill rolling tremor at rest, disappears w/ movement
Rigidity - cogwheel rigidity in extremities
Akinesia/bradykinesia - slowing voluntary movement, expressionless face
Postural instability & shuffling gait
91
What's the histo of Parkinson Disease?
1. Loss of pigmented neurons in the substantia nigra
| 2. Lewy Bodies: Round, eosinophilic inclusions of alpha-synuclein
92
What's a common late feature of Parkinson Disease?
Dementia
| If dementia is early-onset think Lewy body dementia
93
What's Lewy Body Dementia?
Early onset dementia, hallucinations and parkinsonian features
Lewy bodies in CORTEX (gray matter; unlike PD in substantia niagra)
Due to alpha-synuclein defect
94
What's the function of dopamine in the nigrostriatal pathway of the basal ganglia?
Dopamine increased cortical stimulation and increases movement
95
What's Huntington Disease
AD disorder of expanded trinucleotide repeats (CAG) in the huntingtin gene (chrom 4) that leads to degeneration of GABAergic neurons in the caudate nucleus of the basal ganglia
(lateral ventricles look dilated b/c loss of caudate)
96
How does Huntington Disease present and when?
Chorea (C & C = Caudate & Chorea): random firing of cortex movements b/c loss of neg feedback from caudate
Athetosis: involvementary slow movements of fingers
progresses to dementia & depression (suicide common)
Average age at presentation: 40 yo
97
What's normal pressure hydrocephalus? What can it cause and what causes it?
Increased CSF results in dilated ventricles, stretching corona radiata (axons)
Can cause dementia
Usually idiopathic
98
How is CSF absorbed?
Thru arachnoid granulations into the venous sinuses
99
How does Normal Pressure Hydrocephalus present?
"Wet Wobbly and Wacky" Triad
1. urinary incontinence
2. Gait instability
3. Dementia
100
How do you treat normal pressure hydrocephalus?
lumbar puncture improves symptoms
| Ventriculoperitoneal shunting treats it
101
What's spongiform encephalopathy?
Degenerative dx due to prion protein B-PrPsc which is not degradable & converts norm prion protein into pathologic form
102
How's prion protein normally expressed vs expression in spongiform encephalopathy?
Norm: alpha-helical configuration: a-PrPc
Abnorm: Beta-pleated configuration (converted sporadically, inherited or transmitted): B-PrPsc
103
What's the path of spongiform encephalopathy?
Intracellular vacuoles (spongy degeneration) due to B-PrPsc prion protein damaging neurons and glial cells
104
What's the MC spongiform encephalopathy? What causes it and how does it present?
Creutzfeldt-Jakob disease (CJD)
Usu sporadic, rare arises from exposure to prion-infected human tissue (human growth hormone or corneal transplant)
Rapidly progressive dementia (wks- months) assoc w/ ataxia (cerebellum involved) & startle myoclonus (involuntary contraction of muscle w/ lil stimulation)
Periodic sharp-spike waves of EEG
death, usually < 1 yr
105
What's Variant CJD?
special form of dx related to exposure of bovine spongiform encephalopathy ("mad cow")
107
What's an inherited form of prion disease? Characteristics of it?
Familial fatal insomnia
| Characteristics: severe insomnia and exaggerated startle response
108
What % of CNS tumors are metastatic vs primary? Where are the metastatic tumors from?
50% Metastatic (usu well circumscribed and at gray-white junction): lung, breast, kidney
50% Primary: locally destructive but rarely metastasize
109
Where are adults & kid primary CNS tumors usually located?
Adult: supratentorial (cortex)
Kids: infratentorial (cerebellum/brain stem)
110
What are the MC primary adult CNS tumors?
Glioblastoma multiforme, Meningioma & Schwannoma
111
Describe the major tissues and cells in the CNS & their function
1. Glial tissue (50%): astrocytes (form BBB; most abundant), oligodendrocytes (myelinate axons), ependymal cells (like CNS ventricles)
2. Neurons (50% - permenant tissue so don't really divide & rarely become tumors. Exception: neuroectoderm --> medulloblastoma in kids)
3. Meningothelial cells: surround CNS
112
What are the MC primary CNS tumors in kids?
Pilocytic Astrocytoma
Ependymoma
Medulloblastoma (from neuroectoderm)
113
What's Glioblastoma Multiforme (GBM)?
MC primary malignant CNS tumor in adults (high-grade - poor prognosis) from astrocytes
Arises in cerebral hemisphere & crosses corpus callosum (midline structure): butterfly lesion
Grade 4 astrocytoma
114
What are path features of glioblastoma multiforme?
1. Psuedopalisading: regions of necrosis surrounded by tumor & endothelial cell proliferation
2. Butterfly lesion crossing corpus callosum
3. GFAP positive tumor cells (intermediate filament)
115
What is meningioma? Who commonly gets it?
MC benign CNS adult tumor of arachnoid cells that compresses but doesn't invade the cortex.
Usu at convexities of hemispheres and parasagittal region.
Compression causes seizures
MC in women (expresses estrogen receptor)
116
How does meningioma present in imaging and histo?
Imaging: round mass attached to dura
Histo: Whorled pattern spindle cells; Psammoma bodies (laminated calcifications)
117
What's Schwannoma? What does it involve?
Benign tumor of Schwann cells (S-100 positive w/ Antoni A & B (cyst) & verocay bodies
Involves CNs or spinal Ns; w/in cranium usu involves CN VIII at cerebellopontine angle (CPA): presents as loss of hearing and tinnitus
MC in females
118
In what disease state is bilateral schwannoma's seen in?
Neurofibromatosis Type II
119
What is oligodendroglioma? How does it appear in imaging and histo?
Malignant tumor of oligodendrocytes (usu in adults, rare & slow growing)
Imaging: calcified in white matter; usu frontal lobe (may present w/ seizures)
Histo: "fried-egg" appearing cells, chicken-wire capillaries
120
What's pilocytic astrocytoma? Who's it seen in? What's the imaging and histo like?
MC CNS tumor of kids, benign tumor of astrocytes usu in cerebellum/ posterior fossa
Imaging: cystic lesion w/ a mural nodule
Histo:
1. Rosenthal fibers: thick corkscrew eosinophilic astrocyte processes
2. Eosinophilic granular bodies
3. GFAP positive
121
What is medulloblastoma? Who's it seen in? Histo?
Malignant cerebellum tumor (grade 4)from neuroectoderm granular cells. Rapid growth & spread via CSF.
Drop Metastasis: mets to cauda equina
Usu in kids (MC malign tumor in kids)
Histo: Homer-Wright Rosettes: small round blue cells wrapped around pink neuritic processes. Radiosensitive
Can compress 4th ventricle➡️ hydrocephalus
122
What is an ependymoma, who's it seen in and where? Histo?
Malignant tumor of ependymal cells, usu in kids (grade 2)
MC in 4th ventricle➡️ hydrocephalus
Histo: Perivascular pseudorosettes. Basal ciliary bodies (rod-shaped blepharoplasts) near nucleus
123
What is a craniopharygnioma? Where does it present?
Supratentoral benign tumor (tends to recur if resected) from Rathke's pouch (upward protrusion of mouth floor in embryo to form ant pituitary) in midline suprasella
kid of young adult (exception to norm rule for kid CNS tumors)
Calcifications - tooth-like enamel; solid & cystic w/ "motor oil fluid"
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What may a craniopharygnioma do? How is it seen on imaging?
May compress Optic Chiasm causing bitemporal hemianopsia
| Imaging: calcifications (b/c derived from tooth-like tissue)
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What 2 tumors may cause bitemporal hemianopsia?
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Pituitary tumor (adult)
Craniopharyngioma (kid)
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What is the sella turcica?
saddle shaped depression in the sphenoid bone. Hypohyseal fossa that holds the pituitary gland
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How is the pituitary gland formed in the embryo?
Downward protrusion of the base of the brain forms posterior pituitary
Upward protrusion of the floor of the mouth (Rathke's pouch) forms anterior pituitary
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What's Charcot's classic triad of MS?
"MS is a SIN"
Scanning speech
Intention tremor, Incontinence, Internuclear ophthalmoplegia
Nystagmus
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What's Guillain-Barré syndrome?
Acute inflammatory demyelinating polyradiculopathy of peripheral nerves and motor fibers of ventral roots (sensory effects less severe than motor)➡️ symmetrical ascending weakness beginning in lower extremities
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What causes Guillian-Barre syndrome?
Assoc w/ infections leads to autoimmune attack of peripheral nerves due to molecular mimicry, inoculations and stress
Campylobacter jejuni or herpes
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How do u treat a pt with Guillian Barre Syndrome?
Plasmapheresis, IVIG and respiration support till recovery
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What would a pt with Guillian Barre Syndrome CSF look like?
⬆️ protein with norm cell count (albuminocytologic dissociation)
⬆️ protein can lead to papilledema
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What's acute disseminated (post infectious) encephalomyelitis?
Multifocal perivenular inflammation and demyelination after infection (like chickpox or measles) or certain vaccines (rabies, smallpox)
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What's Charcot-Marie-Tooth Disease? What's it also known as?
Aka Hereditary motor and sensory neuropathy (HMSN)
Group of progressive hereditary nerve disorders related to the defective production of proteins involved in the structure and fxn of peripheral nerves or myelin sheath
