CNS Flashcards
____ are the monocyte/macrophage of the CNS
Microglia
What cells make up the myelin sheath in CNS?
Oligodendrocytes
_________:defined as a mean
CSF pressure of more than 200 mm of water
(15 mm of mercury) as measured in the lateral
decubitus position.
Intracranial hypertension:
T/F: IH and brain edema commonly occur together
but do not necessarily coexist
True
• Penetrating wounds and non penetrating injuries • Skull Fractures • Brain disruption/destruction • Closed head injury –Blunt head trauma – Concussion – Contusion
Trauma
\_\_\_\_\_ injuries – Scalp lacerations – Skull fractures – Contusions – Intracranial hemorrhages/hematoma – Lesions secondary to raised intracranial pressure
• FOCAL INJURIES
\_\_\_\_\_\_\_\_ injuries – Global ischemia – Diffuse traumatic axonal injury – Brain edema and swelling
• DIFFUSE INJURIES
clinical syndrome of altered
consciousness secondary to head injury-
sudden disruption of neurologic function.
Concussion:
direct parenchymal injury of the
brain (similar to bruising).
Contusion:
____ injury is caused by the force of the blow to the specific area of brain
Coup injury
____ injury of brain is caused on the opposite portion of the brain as the blow due to the movement of brain
Contre coup injury
______: skull fracture and middle meningeal
artery injury (short period of consciousness
followed by rapidly developing signs of cerebral
compression)
– Epidural hematoma
_______: venous bleeding from bridging veins
(gradual signs of cerebral compression-hours-
days-weeks)
– Subdural hematoma
– Characterized by the widespread but often
asymmetric axonal swellings that appear within
hours of the injury and may persist for much
longer.
– The mechanical forces associated with trauma
are believed to damage the integrity of the axon
at the node of Ranvier, with subsequent
alterations in axoplasmic flow and function.
Diffuse axonal injury (DAI)
______ diseases: They rank as the third major cause of death in
the US after heart disease and cancer
Cerebrobascular diseases
The 4 most common cerebrovascular disorders
are?
global ischemia, embolism, hypertensive
intraparenchymal hemorrhage and ruptured
aneurysm.
____ is the common clinical designation
that applies to relatively acute
cerebrovascular damage of the CNS due to
different disorders.
“Stroke”
_______: destruction and dissection of the
tissue, mass effect. Secondary effects are
frequently necrosis and anoxic/ischemia of the
brain.
Hemorrhage:
What are the 3 CNS diseases involved in Impairment of blood supply and oxygenation:
– Hypoxia, ischemia and infarct (necrosis) of the
brain
______: brief
generally reversible episodes of impaired
neurological function (last <24 hours) –
considered to be precursors of more serious
occlusive events.
Transient ischemic attacks (TIA)-
______: tissue necrosis more frequent than
hemorrhage (75-80%).
• Thrombosis (atherosclerosis) most frequent carotid
bifurcation and middle cerebral artery.
• Embolism: middle cerebral artery most frequent.
• Small infarcts: lacunar strokes (small arteries)
Infarcts:
\_\_\_\_\_\_\_: (20-25%) associated with arterial hypertension, atherosclerosis, vascular malformations, berry aneurysms, trauma, coagulopathy – Intracerebral (arterial hypertension) – Subarachnoid hemorrhage (berry aneurysm of the circle of Willis). – Intraventricular hemorrhage (neonates)
Hemorrhages:
______- Subarachnoid and
intraparenchymal hemorrhages
Berry aneurysms
The brain receives ____% of the cardiac output and consumes
__% of the total body consumption.
15%; 20%
Unlike other organs of
the body, the adult brain burns only _____ as fuel.
glucose
\_\_\_\_: – Low partial pressure of oxygen (PO2) – Impairment of the blood ‘s oxygen-carrying capacity – Inhibition of oxygen use in the tissue
Hypoxia:
_____: transient or permanent interruption of
the normal circulatory flow. Reduction in
perfusion (hypotension), vascular obstruction or
both.
Ischemia:
____ cerebral ischemia: generalized
reduction of cerebral perfusion (cardiac arrest,
shock, severe hypotension)
Global cerebral ischemia:
_______ cerebral ischemia:: localized reduction
or cessation of blood flow to a defined portion
of the brain.
Focal cerebral ischemia:
• Most are intracranial; spinal cord tumors are less
frequent
• Adults: supratentorial
• Children: infratentorial
• Children: second most common malignancy
(leukemia is first)
• Primary CNS tumor rarely metastasizes
• Location important in clinical consequences
• Metastasis to CNS are more frequent than primary in
the general population
CNS Tumors
What is most common CNS tumor in adult?
Metastatic tumor
What are the 4 Main microscopic features in grading (WHO):
– Cellular atypia - A
– Mitosis- M
– Endothelial proliferation E
– Necrosis - N
What is the most common adult primary tumor?
Glioblastoma
• 25% of primary adult tumors –most common adult primary
tumor
• Histologic Features
– Anaplasia, pseudopalisading necrosis, vasc proliferation
• Imaging Characteristics
– Ring-enhancement on MRI
• Average survival < 1 year without treatment; with treatment
only 15 months
Glioblastoma (diffuse)
Are CNS tumors in children more commonly infra or supratentorial?
Infratentorial
- Children
- Infratentorial > supratentorial
- Cystic, contrast-enhancing
- Rosenthal fibers and EGBs (eosinophilic granular bodies)
- Localized tumor
- Generally favorable outcome (WHO 1)
Pilocytic astrocytoma (Localized)
- Adults (4th-5th decades)
- WHO grades II, III
- Diffuse
- White matter
- Calcification
- Better prognosis than astrocytoma
Oligodendroglioma
• Childhood/adolescence • Intracranial in children (often fourth ventricle) • Spinal cord in adults • Ependymal rosettes and perivascular pseudorosettes • WHO grade I –III, grade II most common
Ependymoma
• Pediatric, WHO grade IV neoplasm
• Small round blue cell tumor
• Located in the cerebellum
• Despite the WHO grade IV designation, this tumor
has a very favorable prognosis in many cases
Medulloblastoma
• Second most common primary intracranial tumor in
adults > 30 years > Female
• Benign behavior, slowly growing
• Convexities of the cerebral hemispheres and
parasagittal region; other falx cerebri, sphenoid
ridge, olfactory area, suprasellar region
Meningioma
- Cranial nerve VIII (cerebellopontine angle)
- Antoni A, Antoni B
- Verocay bodies
- Benign
- Neurofibromatosis type 2
Schwannoma
• Gray-white junction • Often multiple lesions • Older adults • 25-30% of all CNS tumors • Most common: – Lung – Breast • Often hemorrhagic – Kidney – Melanoma – Choriocarcinoma
Metastases CNS tumor
____ is the 3rd most common intracranial primary tumour in adults
Schwannoma
inflammation of the brain
Encephalitis:
inflammation of the meninges
Meningitis:
inflammation of the brain and
meninges
Meningoencephalitis:
inflammation of the meninges,
brain and spinal cord
Meningoencephalomyelitis:
inflammation of the spinal cord and its
membranes
Meningomyelitis:
• Hematogenous spread is most common • Trauma • Local spread from paranasal sinuses, dental infections, skin (facial) infections • Peripheral nerves (viruses)
Infections
• Meningitis: peak incidence in children (75% of
cases)
• Etiology:
– Neonates and infants: group B strep, E. Coli, Listeria
– Older infants and young adults: Strep Pneumoniae
(pneumococcus) and Neisseria meningitides
– Older adults: S Pneumoniae and Gram negative bacilli
Bacterial meningitis
• Penetrating skull injuries
• Spread of infection from other sources: Para nasal
sinuses, middle ear (most common source), infective
endocarditis, bronchopulmonary infections, and
other sources
• May be bacterial or fungal in origin
Cerebral abscess
• Multiple necrotizing abscesses, some hemorrhagic, in basal ganglia and cortico- subcortical junction • Look for free tachyzoites at periphery of necrotic lesions
Toxoplasmosis
\_\_\_\_\_\_ encephalitis • Arbovirus: St Louis Encephalitis, western equine encephalitis, West Nile • Herpes Simplex • Cytomegalovirus (CMV) • HIV infection (progressive dementia, vacuolar myopathy) • Poliomyelitis • Rabies
Viral Meningitis-Encephalitis
_______ encephalitis
• Lytic and hemorrhagic process distributed in an
asymmetric fashion throughout the medial temporal
and inferior frontal lobes
• Untreated is progressive and often fatal in 7-14
days
Herpes simplex encephalitis
• Rare in adults, typically immunocompromised
• Important in pregnancy and early postnatal period
• One of the TORCH infections
• Causes periventricular calcifications
• Viral particles in brain and persist for decades after fetal
infection
CMV
• Opportunistic demyelinating disease caused by the JC
polyomavirus (JCV)
• Most common in immunocompromised patients
• Classical histopathology is that of a multifocal white matter
disease with demyelination secondary to extensive involvement
of oligodendrocytes by JCV infection
• Diagnostic hallmark = presence of oligodendrocytes with
enlarged nuclei containing intranuclear amphophilic inclusions,
as well as astrocytes with bizarre, malignant appearing nuclei in
areas of demyelination
PML
______ are abnormal forms of a cellular protein that causes
transmissible neurodegenerative disorders.
• Creutzfeldt-Jakob disease (CJD)
• Scrapie in sheeps and goats
• Bovine spongiform encephalopathy
Prions
Normal ___ is a 30 kD protein present in neurons.
PrP
Disease occurs when the PrP undergoes modification
to an abnormal b-pleated sheet isoform termed
______
PrPsc
______ is characterized by more than one episode of neurologic
deficits separated in time, attributable to CNS white matter lesions
that are separated in space.
▪ Lesions initially involve destruction of myelin; axonal damage may
occur later in the process.
• On MRI, findings of multifocal lesions of various ages, especially
those involving the periventricular white matter, brainstem,
cerebellum, and/or spinal cord white matter, support the clinical
impression
▪ Gross pathology: Multiple areas of demyelination
(plaques) in white matter of the brain and spinal
cord (NOT the peripheral nervous system),
frequently located adjacent to lateral ventricles
(periventricular).
Multiple sclerosis
• MC neurodegenerative disease causing dementia
• Pathologic findings are though to develop well in advance of
significant clinical deficits and may be seen in younger
patients
• Pathologic hallmarks = neuritic plaques and neurofibrillary
tangles in combination with neuronal loss
• Onset before age 50 should raise the possibility of a familial
form of disease
Alzheimer disease
• Neurodegenerative disorder characterized by the presence of
Lewy bodies in neurons of various cortical structures
• Characterized by severe loss of substantia nigra (SN)
dopaminergic neurons, visible in brain sections as
depigmentation of the substantia nigra in the midbrain.
Parkinson disease
