Martin: Intro, CV disease, & Infection Flashcards
1
Q
Which cell type is evident 12-24 hrs after acute CNS hypoxic/ischemic insult?
A
Red neurons (“red dead guys”)
2
Q
Morphology of red neurons
A
- Shrinkage of cell body
- Pyknosis of nucleus
- Dissapearance of nucleolus
- Loss of nissl substance
- Intense eosinophilia of the cytoplasm
3
Q
What are the hallmarks of subacute and chronic neuronal injury (i.e., degeneration)?
A
- Cell loss —> Apoptosis
- Reactive gliosis
4
Q
What is gliosis?
A
Proliferation of astrocytes in response to brain injury
5
Q
What is the axonal reaction?
Best seen where?
A
- Change observed in cell body during regeneration of the axon
- Best seen in anterior horn cells of SC when motor axons cut
6
Q
Most important histopathologic indicator of CNS injury regardless of etiology?
Characterized by what 2 things; what cell?
A
- Gliosis
- BOTH hypertrophy and hyperplasia of astrocytes
7
Q
Which cells of the CNS are most sensitive to insult?
A
- Pyramidal neurons (hippocampus)
- Neocortical Betz cells
- Cerebella purkinje cells
8
Q
Intracellular inclusions seen in herpes, rabies and cytomegalovirus?
Where specifically in the cell is each seen?
A
- Cowdry body (intranuclear): herpes
- Negri body (intracytoplasmic): rabies
- Both nucleus and cytoplasm: CMV
9
Q
Intracytoplasmic inclusions seen in Alzheimer’s and Parkinson disease?
A
- Neurofibrillary tangles: Alzheimer’s disease
- Lewy bodies: Parkinson’s disease
10
Q
__________ act as the metabolic buffers and detoxify the brain; also contributing to the BBB (foot processes)
A
Astrocytes
11
Q
What is the intermediate filament found in Astrocytes and can be stained for?
A
GFAP
12
Q
Gliomas are positive for which stain?
A
GFAP
13
Q
What type of astrocyte is seen in pt’s with long-standing hyperammonemia due to chronic liver disease (will have flapping tremor of hands with extension of the wrist, asterixis), Wilson disease, or hereditary metabolic disorders of the urea cycle?
A
Alzheimer Type II Astrocyte
14
Q
What type of cytoplasmic inclusion bodies are characteristic of Pilocytic Astrocytoma and also found in regions of long standing gliosis?
A
Rosenthal fibers
15
Q
Which heat-shock proteins are found in Rosenthal Fibers?
A
- αB-crystallin
- hsp-27
*Also ubiquitin
16
Q
What is Alexander disease and what cellular changes are seen in this disease?
A
- Leukodystrophy due to mutation in GFAP
- Rosenthal fibers, but more commonly seen are corpora amylacea (aka polyglucosan bodies)
17
Q
Corpora amylacea (aka polyglucosan bodies) are positive for which stain?
A
PAS positive
18
Q
______ are mesoderm derived phagocytic cells that serve as resident macrophages of the CNS
A
Microglia
19
Q
Which round, faintly basophilic, concentrically lamellated structures increase with age and are though to represent degenerative changes in the astrocyte?
A
Corpora amylacea (aka polyglucosan bodies)
20
Q
What are the cell surface markers of Microglia?
A
CR3 and CD68
21
Q
What are 4 ways microglia respond to injury?
A
1) Proliferation
2) Dev. elongated nuclei (rod cell), as in neurosyphillis
3) Microglial nodules: microglia aggregate around small foci of necrosis
4) Neuronophagia: microglia congregate around cell bodies of dying neurons
22
Q
How does the myelination ability of oligodendrocytes differ from schwann cells?
A
- Oligodendrocytes myelinate numerous internodes on multiple axons
- Schwann cells in peripheral nerve, has a one-to-one correspondance between cells and internodes
23
Q
Injury or apoptosis of __________ cells is a feature of acquired demyelinating diseases and leukodystrophies?
A
Oligodendroglial cells
24
Q
What are Ependymal cells and where are they found in the CNS?
A
Ciliated columnar epithelial cells lining the ventricles
25
Disruption of the ependymal lining and prolferation of subependymal astrocytes produces what on ventricular surfaces?
Ependymal granulation
26
Which agent may produce extensive ependymal injury, with viral inclusions in ependymal cells?
CMV
27
What is the response of microglia to neuronal injury?
Proliferate and accumulate during CNS injury
28
What is Vasogenic edema and is often seen following what?
- Increased **EXTRAcellular** fluid due to **BBB disruption** and **increased vascular permeability**
- Fluid shifts from INTRAvascular compartments to INTERcellular spaces
- Can be either **localized** (i.e., adjacent to neoplasms or inflammation) or **generalied** often follows **ischemic injury**
29
What is Cytotoxic edema and when is it seen?
- Increase in **INTRAcellular** fluid secondary to neuronal, glial, or endothelial cell membrane injury
- Generalized hypoxic/ischemic insult or w/ metabolic derangment
30
What is the most common cause of **noncommunicating (obstructive) hydrocephalus** in the neonate/infant?
Aqueductal stenosis
31
Enlargement of the **entire** ventricular system ("**symmetric dilation"**) due to accumulation of CSF not being properly absorbed at the _dural sinus level_ is known as?
Communicating ("non-obstructive") hydrocephalus
32
What 2 congenital conditions cause ventricular system obstruction?
1) Acqueductal stenosis
2) Dandy-Walker malformation
33
What is **Hydrocephalus Ex-Vacuo**?
Whom is it seen in?
What is the CSF pressure?
- Compensatory increase in ventricular volume secondary to loss of brain parenchyma
- **Atrophy** with increasing age, **stroke** or other injury, **chronic neurodegenerative** disease
- **CSF pressure is NORMAL!!!**
34
Herniation is displacement of brain tissue due to _____ or \_\_\_\_\_\_
**Mass effect** or **Increased intracranial pressure**
35
Subfalcine herniation involves displacement of the _______ under the \_\_\_\_\_\_\_
**Cingulate gyrus** under the **falx cerebri**
36
Subfalcine herniations can compress which vessel?
Anterior cerebral artery
37
Transtentorial (uncinate, mesial temporal) herniation occurs when?
Which **specific** part and of which lobe?
**MEDIAL aspect** of the **TEMPORAL** **lobe** is compressed against the free margin of the tentorium
38
What are 3 possible consequences of progression of **transtentorial** **herniations**?
1) Compression of **CN III** ---\> _pupillary_ dilation; eye is "_down_ and out" (ipsilateral to lesion)
2) Compression of **PCA** ---\> ischemia of primary _visual_ _cortex_
3) Large herniation may compress contralateral **cerebral peduncle** ---\> _hemiparesis_ _ipsilateral_ to side of herniation = *Kernohan notch* = "false localizing sign"
39
What are Duret hemorrhages and are a result of what?
- Progression of **transtentorial herniation** producing secondary hemorrhagic lesions in the **midbrain** and **pon**
## Footnote
**- "Flame-shaped" lesions**
40
What are congenital causes of hydrocephalus?
- Intrauterine infections (TORCH)
- Agenesis/atresia/stenosis
- Arnold chiari malformations
- Dandy walker syndrome
- Cranial defects: Achondroplasia and Craniostenosis
41
What is the most common **parasitic** nervous system disease in the world and can lead to _hydrocephalus_?
- Cysticercosis
- *Taenia Solium* (pork tapeworm)
42
What are the characteristic of **normal pressure hydrocephalus** and who is it seen in?
- Symmetric type usually occuring in **adults \>60**
- Develops slowly over time; drainage of CSF is _blocked_ gradually
- **Wet** (incontinence), **Wacky** (dementia), **Wobbly** (ataxia)
43
A right hemisphere **trans-tentorial herniation**, causes a Kernohan's notch in the _____ cerebellar peduncle, which results in ________ motor impairment.
A **right** hemisphere trans-tentorial herniation, causes a Kernohan's notch in the **left** cerebellar peduncle, which results in **right-sided** motor impairment.
44
What is a **tonsillar** **herniation** and why is it life threatening?
- Displacement of the cerebellar **tonsils** through the **foramen magnum**
- Can can brainstem compression and compromises vital _respiratory_ and _cardiac_ centers in the medulla
45
\_\_\_\_\_\_\_ refers to a diverticulum of disorganized **brain tissue** extending through a defect in cranium; most often occurring in the **posterior fossa**
Encephalocele (sometimes misleadingly referred to as a "nasal glioma")
46
Malformation of the **anterior end** of the neural tube leading to a "frog-like" apperance of a fetus is known as?
Anencephaly
47
The cause of Microcephaly is linked to?
- Chromosomal abnormalities
- **Fetal alcohol syndrome**
- **HIV-1** acquired in utero
- **Zika**
48
What is Lissencephaly and the 2 general patterns observed?
- Reduction in the # of gyri; sometimes **agyria** = NO gyri
49
What term describes neurons in innaprpriate places?
**Neuronal heterotopia**: assc w Epilepsy
50
Which forebrain anomaly is characterized by small, unusually numerous, irregularly formed cerebral convolutions? Leads to extra thick cortex
Polymicrogyria
51
What is Holoprosencephaly? Severe forms produce which abnormalities?
- Incomplete separation of the cerebral hemispheres across the midline
- **Cyclopia** from midline abn
- **Arrhinencephaly** from absence of olfactory CNs
52
Holoprosencephaly is associated with what disease and signaling mutation?
- Trisomy **13**
- **Sonic hedgehog** signaling pathway
53
Radiologic imaging showing a "bat wing" deformity is associated with that condition?
Agenesis of the corpus callosum
54
What is an **Arnold-Chiari Type II** malformation and what other abnormalities is it associated with?
- Type 2 = _more severe_
- Vermis extends down into foramen magnum
- Assc w hydrocephalus and **myelomeningocele**
55
What is an **Arnold-Chiari Type I** malformation?
- Type 1 = less severe & sometimes asymptomatic
- Cerebellar **tonsils** extend down vertebral canal
- May present w _HA's_ if CSF flow is impaired
56
Which condition is associated with an **enlarged** posterior fossa, absence of cerebellar vermis w/ replacement by a large midline cyst representing an **expanded roofless 4th ventricle**?
Dandy-Walker Malformation
57
Which condition has hypoplasia of the cerebellar vermis, elongation of the cerebellar peduncle and an altered shape of brainstem; together giving a 'molar tooth sign' on imaging?
Joubert syndrome
58
Syringomyelia is associated with what other condition; how does it present?
What part of the spinal cord is involved?
- Associated w/ Arnold-Chiari Malformations
- S/s: pain & temp loss of both UE (cape-like syrinx)
- Central canal of spinal cord grows, interrupting the fibers in the **anterior white commisure**
59
Expansion of the ependyma-lined central canal of the spinal cord is known as \_\_\_\_\_\_\_\_.
Hydromyelia
60
What is Cerebral Palsy and what are the clinical manifestations of this disease?
Occurs due to insults during which period?
- **Non-progressive** neurologic motor deficits characterized by combination of spasticity, dystonia, ataxia/athetosis, and paresis
- Pre-natal and perinatal periods (are present from birth)
61
What type of hemorrhage is seen in the germinal matrix of premature infants?
- **Intraparenchymal hemorrhage**
- Junction between **thalamus** and **caudate nucleus**
- May extend into ventricles ---\> subarachnoid space ---\> hydrocephalus (obstructive)
62
Infarcts may occur in the supratentorial white matter of premature infants and are known as?
Characteristic finding?
- **Periventricular leukomalacia**
- _Chalky yellow plaques_ = white matter necrosis and calcification
63
Extensive ischemic damage of both **white and gray matter** leading to large cystic lesions during the perinatal period is known as?
- Multicystic encephalopathy
64
Diastatic fracture
Fracture that **crosses a suture**
65
Clinical term for altered consciousness secondry to a head injury typically brough about by a change in momentum of the head
Concussion
66
What is the morphology of a brain contusion?
- **Wedge shaped** w/ a broad base lying along the surface at the point of impact
67
What term describes an old traumatic lesion?
Term for contusion at point of impact and the opposite of that?
- **Plaque Jaune**: old lesion. Yellow/brown patches.
- **Coup**: contusion at point of impact
- **Contrecoup**: contusion on opposite of side impact bc of _sudden decel_
68
Diffuse axonal injury is best demonstrated using what lab techniques/stains?
- **Silver impregnantion (silver stain)**
- Immunoperoxidase stains for **amyloid precursor protein** and **α-synuclein**
69
Sudden onset of severe headache ("worst headache of my life"), often with rapid neurologic deterioration is consistent with a _________ hemorrhage
Subarachnoid
70
Secondary injury associated seen in subarachnoid hemorrhage is often associated with what?
Vasospasm
71
A patient presents after a direct blow to the head which initially knocked him unconscious, **after 1hr** he begins to exhibit neurological deterioration, what do you suspect?
Epidural hematoma = rapid neuro sx develop
Assc w skull fracture
72
What type of hematoma is associated with rupture of the **bridging veins**?
Subdural hematoma
73
Which patient populations are at higher risk for subdural hematomas?
- **Elderly** w/ brain atrophy due to increased stretching of the bridging vein
- **Infants** due to thin-walled bridging veins
74
What is seen in the brains of individuals with CTE (dementia pugilistica) during a post-mortem autopsy?
- Atrophic w/ **enlarged ventricles**
- Accumulation of **tau**-containing neurofibrillary **tangles**
- Characteristic pattern involving superficial frontal and temporal lobe cortex
75
Border zone ("watershed") infarcts are usually seen after ________ episodes
Hypotensive
76
What are the subacute changes seen 24 hours to 2 weeks after global ischemia?
- Tissue necrosis
- Influx of **M****acrophages and Reactive gliosis (10 days)**
- **Vascular proliferation**
77
Global cerebral ischemia occurs after which events?
Cardiac arrest, shock, or severe hypotension
78
Which artery is most frequently affected by embolic infarction?
MCA --- direct extension of the internal carotid artery
79
Widespread hemorrhagic lesions involving the white matter are characteristic of embolization of _______ after trauma
Bone marrow
Aka **shower emboli**
80
Most common sites for thrombotic occlusions in the brain
- Carotid bifurcation
- Origin of MCA
- Either end of Basilar artery
81
Thrombolytic therapy following an infarct is contraindicated in?
**Hemorrhagic infarcts** --\> may cause extensive intracerebral hematomas
82
Infarcts are often initially nonhemorrhagic, but secondary hemorrhage can occur from ______ injury
Ischemia-reperfusion
83
What are the most common locations for lacunar infarcts?
- Lenticular nucleus
- Thalamus
- Internal capsule
- Deep white matter
84
How can HTN lead to the development of lacunar infarcts?
Cerebral vessels develop **arteriolar sclerosis** and may become **occluded** ---\> Lacunes aka small lakes
85
Small slit like cavity that is surrounded by a brownish discoloration after reabsorption of a hemorrhage is known as what?
Slit hemorrhage
86
Hypertensive encephalopathy is a consequence of?
Malignant hypertension
Assc w deep brain parenchymal hemorrhages
87
Patients who have **bilateral gray and white matter infarcts over many months and years** may develop what distinct clinical syndrome characterized by _dementia, gait abnormalities, pseudobulbar signs_ and other focal neuro deficits?
Vascular (multi-infarct) dementia
88
What is the risk factor most commonly associated with deep brain parenchymal hemorrhages?
HTN
89
What causes Charcot-Bouchard microaneurysms?
Chronic HTN
90
What is a Charcot-Bouchard microaneurysm vs. Saccular (berry) aneurysm?
Where is each most commonly seen?
- Charcot-Bouchard occur in vessels less than 300 um in diameter; most often within **basal ganglia** from _lenticulostriate_ arteries
- Saccular (berry) aneurysms occur in _branch_ points of **anterior circulation** and cause SAH
91
What is the risk factor most commonly associated with lobar hemorrhages?
Cerebral amyloid angiopathy (CAA)
92
What is the mutation associated with Cerebral Autosomal Dominant Arteriopathy w/ Subcortical Infarcts and Leukoencephalopathy (CADASIL)?
NOTCH3
93
Cerebral Autosomal Dominant Arteriopathy w/ Subcortical Infarcts and Leukoencephalopathy (CADASIL) is characterized clinically how?
Recurrent strokes (usually infarcts, less often hemorrhages) and dementia
94
Most frequent cause of clinically significant **subarachnoid hemorrhage** is rupture of?
Saccular (berry) aneurysm
95
There is an increased incidence of saccular (berry) aneursyms in people with what disorders?
- AD polycystic kidney disease
- Ehlers-Danlos type IV
- NF1
\*Smoking and HTN are risk factors
96
What is the most common site for Arteriovenous Malformations?
MCA; particularly its posterior branches
97
Who is most at risk for Arteriovenous Malformations?
How does it present?
- **Males** twice as frequently; between **ages 10-30**
- Presents as seizure disorder, intracerebral hemorrhage, or subarachnoid hemorrhage
98
Morphology of Arteriorvenous Malformations
**Tangled vessels ("worm-like")** that show prominent, pulsatile arteriovenous shunting with high blood flow -- **bypass a capillary bed**
99
Waterhouse-Friderichsen syndrome results from?
Occurs most commonly due to meningitis caused by?
- Meningitis-associated septicemia w/ hemorrhagic infarction of the **adrenal glands** and **cutaneous petechiae**
- Meningococcal and pneumococcal meningitis
100
What is chemical meningitis?
Nonbacterial irritant introduced into the subarachnoid space
101
How can hydrocephalus result from pyogenic meningitis?
Particularly with what organism?
- Capsular polysaccharide of **pneumococcal meningits** produces a gelatinous exudate that promotes arachnoid **fibrosis**
- Referred to as **chronic adhesive arachnoiditis**
102
What are predisposing conditions for the development of a brain abscess?
- Acute bacterial endocarditis
- Congenital heart disease (w/ right to left shunting)
- Immunosuppression
103
Discrete lesions in the brain with **central liquefactive necrosis** _surrounded by brain edema_ is characteristic of?
Brain Abscess
104
Most common bacteria in brain abscesses of non-immunosuppressed patients?
- Streptococci
- Staphylococci
105
Extradural abscess are commonly associated with?
Osteomyelitis
106
What are the common causes of chronic bacterial meningoencephalitis?
- *Mycobacterium tuberculosis*
- *Treponema pallidium*
- *Borrelia* species
107
The most serious complications of chronic tuberculosis meningitis are ________ producing hydrocephalus, and ________ producing arterial occlusion and infarction of underlying brain
The most serious complications of chronic tuberculosis meningitis are **arachnoid fibrosis** producing **hydrocephalus**, and **obliterative endarteritis** producing arterial occlusion and infarction of underlying brain
108
What stain is used to look for TB infection?
Acid-fast
109
Which form of neurosyphilis involves the base of the brain and may cause communicating hydrocephalus?
Meningovascular neurosyphilis
110
How does paretic neurosyphilis clinically manifest?
- *T. pallidum* (spirochete)
- Progressive cognitive impairment associated with **mood alterations** (including delusions of grandeur)
- Terminates in severe dementia (**general paresis of the insane**)
\*\*will see perivascular _iron_ deposits
111
Tabes dorsalis results from damage to?
**Dorsal column** medial lemniscus system (posterolateral columns, fasciculus cuneatus and gracilis)
112
Which condition presents with **widened gait**, impaired **joint position** sense and **ataxia**, loss of pain sensation leading to skin and joint damage (**Charcot joints**), characteristic "**lightning pains**," and **absence of DTRs**?
Tabes dorsalis
113
What are the neurologic symptoms associated w/ Neuroborreliosis (Lyme Disease)
Lyme pie to the **FACE**
**F-** facial nerve plasy
**A-** arthritis
**C-** cardiac block
**E-** erythema migrans
\*\*develop 4wks after rash (bell's and peripheral neuropathy)
114
Which virus is an important cause of **epidemic encephalitis**, especially in tropical regions of the world?
Arbovirus
115
Involvement of the spinal cord in West Nile encephalitis can lead to ________ syndrome w/ paralysis
Polio-like syndrome w/ paralysis
116
HSV-1 has a tropism for which lobes of the brain; what type of injury is seen when infected?
- Temporal lobes and orbital gyri of the frontal lobe
- Hemorrhagic lesions w/ Cowdry type A intranuclear viral inclusion bodies within neuron and glia
117
What does HSV-2 cause particularly in neonates born by vaginal delivery to a woman with active primary HSV genital infections?
Severe encephalitis
118
In immnosuppressed individuals, CMV most commonly causes?
Subacute encephalitis
119
Periventricular leukomalacia is characteristc of infection by which virus?
CMV
120
Poliovirus has a tropism for which neurons of the spinal cord?
Anterior horn motor neurons
121
CMV infection is confirmed by?
Immunohistochemistry
122
How does CNS infection by poliovirus present initially and what are the CSF findings?
- Meningeal irritation
- CSF consistent w/ aseptic meningitis (pleocytosis of lymphocytes, moderately elevated protein, nearly normal glucose)
123
What is post-polio syndrome?
- Happens to pt's 25-35 years after the resolultion of initial illness
- Characterized by progressive weakness and decreased muscle mass and pain in the affected area
124
Negri bodies associated with rabies infection are found where in the brain?
- Pyramidal neurons of the hippocampus
- Purkinje cells of the cerebellum
\*Sites usually devoid of inflammation
125
Which symptoms/findings are virtually diagnostic for rabies infection?
Malaise, headache and fever in conjunction w/ **local paresthesias around the wound**
126
What is seen during the acute phase of HIV infection of the CNS?
Mild lymphocytic meningitis, perivascular inflammation, and some myelin loss
127
What are the only CNS cell type to express both the CD4 coreceptor and the chemokine receptors (CCR5 or CXCR4) that are required in combination for efficient infection by HIV?
Microglia
128
What is immune reconstitution inflammation syndrome (IRIS)?
- Seen in AIDS patients
- Paradoxical deterioration after starting therapy and consists of an exuberant "reconstituted" inflammatory response while on antiretroviral therapy
- Intense inflammation w/ influx of CD8+ lymphocytes
129
What type of encephalitis is associated with **widely distributed microglial nodules**, often containing macrophage-derived multinuclated giant cells?
HIV encephalitis
130
Which virus causes Progressive Multifocal Leukoencephalopathy (PML)?
This virus has tropism for which cell, and what is its principle pathologic effect?
- JC polyomavirus
- Tropism for oligodendrocytes ---\> **demyelination** is its principal pathologic effect
131
Progressive Multifocal Leukoencephalopathy (PML) occurs almost exclusively in who?
Immunosuppressed individuals
132
Which encephalitis is characterized by patches of irregular, ill-defined white matter injury w/ **enlarged oligodendrocyte nuclei containing glassy amphopilic viral inclusions**?
Progressive Multifocal Leukoencephalopathy (PML)
133
Which encephalitis is characterized by **widespread gliosis and myelin degeneration**; **viral inclusions**, largely within the nuclei of oligodendrocytes and neurons; variable inflammation of white and gray matter; and neurofibrillary tangles?
Subacute Sclerosing Panencephalitis (SSPE)
134
How do most fungi reach the brain; what is another way they may invade?
- Most by hematogenous dissemination
- Direct extension may also occur, particularly **mucormycosis** in the setting of **diabetes mellitus**
135
What are the 3 main forms of injury to the CNS caused by fungal infections?
1) Chronic meningitis
2) Vasculitis
3) Parenchymal invasion
136
Vasculitis associated with fungal infections is most frequently seen with what organisms?
*Mucormycosis* and *Aspergillosis*
137
What are the most commonly encountered fungi that invade the brain?
*Candida* and *Cryptococcus*
138
Gelatinous material within the subarachnoid space and small cysts within the parenchyma (**"soap bubbles"**), especilly within the basal ganglia are characteristic of what type of infection?
Chronic meningitis associated w/ **cryptococcal infection**
139
What may be seen on CT with cerebral toxoplasmosis infection?
Ring enhancing lesions
140
What is the morphology of cerebral toxoplasmosis abscesses; most often seen where?
- Mostly affect the cerebral cortex (near the gray-white junction) and deep gray nuclei
- Central necrosis, petechial hemorrhage surrounded by acute and chronic inflammation, macrophage infiltration, and vascular proliferation
141
Which stain is used for *Naegleria* species to confirm a diagnosis of cerebral amebiasis?
PAS or Methenamine silver
142
Cerebral malaria is a rapidly progressing encephalitis caused by what organism?
*Plasmodium falciparum*
143
What are the clinical implications of infection with *Taenia Solium* causing cysticercosis?
- Form cysts within the subarachnoid space
- May obstruct CSF flow, leading to life threatening hydrocephalus
- Hemiplegia, severe headaches, and papilledema
144
Heterozygosity at which codon is protective against the development of diseases associated with prion protein (PrP)?
129
145
What are the clinical manifestations of Creutzfeldt-Jakob Disease (CJD)?
Subtle changes in memory/behavior followed by a **rapidly progessing dementia**, often associated with **pronounced involuntary jerking muscle contractions** on sudden stimulation (**startle myoclonus**)
146
Creutzfeldt-Jakob Disease (CJD) has a peak incidence during what decade?
How is it transmitted?
Average survival time?
- During the **seventh decade**
- **Iatrogenic transmission**, notably by corneal transplantation, deep implantation of electrodes in the brain, and administration of contaminated preparations of naturally derived GH
- Average survival = 7 months
147
Onset of the variant form of CJD is linked to consumption of?
Bovine spongiform encephalopathy agent in contaminated foods or blood transfusion
148
How does vCJD differ clinically from CJD?
- Behavioral changes early in the disease
- **Slower progression** of neurologic symptoms
149
What is seen on electron microscopy with CJD and vCJD?
How are they stained?
- **Kuru plaques:** extracellular deposits of aggregated abnormal protein (will have **halo** of spongiform in vCJD); usually seen in the **cerebellum**, but are abundant in the **cerebral cortex in cases of vCJD**
**- Congo red** and **PAS-positive**
150
Fatal Familial Insomnia (FFI) is caused by what specific mutation in the *PRNP* gene?
**Aspartate** substitution at residue **129** or PrPc
151
What is the characteristic morphology of Fatal Familial Insomnia (FFI)?
- Neuronal loss and reactive gliosis in the **anterior ventral** and **dorsomedial nuclei** of the **thalamus**
- Neuronal loss is also prominent in the **inferior olivary nuclei**
152
What are the clinical manifestations of Fatal Familial Insomnia (FFI)?
- Sleep disturbances in the initial stages
- Ataxia, autonomic disturbances, stupor, and finally coma
153
Polymorphisms at which codon influence the development of prion diseases?
Codon 129 encoding either Met or Val
154
How does FFI differ from the other prion diseases, morphologically?
Does **not** show spongiform pathology
155
Where are the densest amounts of exudate found with acute meningitis caused by *P**neumococcal meningitis* and *H. influenzae?*
- ***P. meningitis***: often densest over convexities near sagittal sinus
- ***H. influenzae:*** usually basal location
156
What might have caused this on MRI?
Flat brain w surrounding hydrocephalus
Choroid Plexus Papilloma
157
Which skull fracture will cause orbital and mastoid hematomas?
Basilar skull fracture
158
# Define chronic traumatic encephalopathy? (CTE)
What are these pt's more susceptible to?
A brain disease linked with **repeated head blows**
Inc risk of: **AD, PD,** atrophy
159
How do we ID Shaken Baby Syndrome?
Shaking a baby stops the crying bc brain damage
ID with _prussian blue stain_ to look for **iron**
Also may see: SAH, retinal hemorrhage, subdural hematoma
160
Epidural hematomas are caused by which vessel generally?
- Caused by **middle meningeal artery** usually 2nd to skull fracture
- S/s: rapid deterioration, transtentorial herniation, CN3 palsy
Imaging: smooth contours of hematoma
161
What are the 2 assc with Berry Aneurysms?
ADPKD
Ehler-Danlos
NF1
Marfan
162
What are the clinical sx assc w loss of ACA?
ACA
* **Contralat** hemiplegia: **leg** more than arm/face
* **Alien hand syndrome**: contra arm not under voluntary control
163
What are the clinical sx assc w loss of PCA?
PCA = Contralat homonymous hemianopia with macular sparing
\*\*\*affects **Occipital lobe**
164
What are the clinical sx assc w loss of MCA?
MCA = most common place for infarcts and ischemia
* **Aphasia**, hemineglect, hemianopia, **face-arm** sensorimotor loss
* **Gaze preference** TO side of lesion
165
What shape indicates a water-shed infarct?
**Sickle** shaped band of necrosis
166
What causes ACA-MCA infarction?
What are the assc sx?
- Cause = **occlusion** of the internal carotid artery OR **hypotension** w carotid artery stenosis
- S/s: **proximal** **arm/leg** weakness & **transcortical** **aphasia**
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What are the sx of MCA-PCA infarction?
Loss of higher order **visual processing**
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What is significant about TIAs?
TIAs are a warning sign for larger ischemic event (15% of pt in 3mo)
**Neurological emergency &** all pt should be emergently _admitted_
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Hemorrhagic vs Ischemic infarction
* **Hemorrhagic**: _emboli_ assc.
* Bleeding 2nd to _reperfusion_
* Cause: A fib, carotid stenosis, DVT w PFO, endocarditis
* **Ischemic**: _thrombus_ assc.
* Clot forms at site of occlusion
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Where do most saccular aneurysms happen?
What is the underlying defect
Anterior ciruclation: **ACA** and **AComm**
No **media** of vessel at branch points - more susceptible to stretch
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What are the 4 routes of CNS infection?
1. **Hematogenous**: most common
2. Direct implantation
3. Local extension: teeth, sinus
4. **Peripheral NS**: rabies, herpes
CSF exchange happens q3-4hrs, so brain is washed in bacteria
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What is the cause of subdural empyema?
What is a possible complication?
Subdural empyema caused by infection of skull bones or **sinus infection** spreading to subdural space
May cause thrombophlebitis is veins -- leads to **infarction**
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What are CSF findings with brain abscess?
High WBC, High protein, Nml glucose
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What will be in the CSF of a pt w Lyme disease?
CSF = ab
\*\*ab can cross-react w other infectious agents: mono, RA, SLE, syphylis
