Red Neuron: acute global ischemia
eventual repair of global ischema
gliosis
never bands of destruction
pseudolaminar necrosis
acute neuronal injury.
shrunken cell body, intense eosinophilia
Seen in acute CNS hypoxia/ischemia
earliest morph marker of neuronal cell death
What do Red Neurons indicate?
indicates injury
most important histiopathologic indicator
-astrocyte cytoplasm expands, bright pink
Gliosis
phagocytic cells/macrophage of the CNS
- develop elongated nuclei, aggregate around areas of tissue necrosis
what are Microglia?
increased ECF due to BBB disruption. Fluid moves from intravascular to intercellular space
Vasogenic
flattened gyri, narrowed sulk, compressed ventricular cavities
Cerebral Edema Generalized morphology consists of what?
Brain edema
- Accumulation of excess CSF w/in ventricular system.
- Choroid plexus produces CSF
- most cases are due to impaired flow and resorption of CSF
Hydrocephalus
1. Obstructive (aqueductal steoisis, lesion in ventricular system)
2. Non-obstructive (impaired resporption, over production)
3. Unspecified (x-linked)
Types of Hydrocephalus
communicating hydrocephalus: ventricle system "communicates" with subarachnoid space
a mass is blocking the third ventricle - a mass non-communicating hydrocephalus
obstructive
What does this indicate?
holy hydrocephalus
compensatory increase in ventricle volume due to loss of brain parenchyma (alzheimers) - not a loss of brain function
Hydrocephalus-ex-vacuo
displacement of brain tissue past riding dural folds - falx and tantorium, openings in skull. Due to increase ICP. Due to edema or tumor or hemorrhage
subfalcine or cingulate: expansion of one hemisphere pushes the cingulate gyrus under the fall
Tonsillar
Herniation **
brain tissue herniates across compartments in brain
almost always associated with mass effect (edema, focal). Can be accompanied by transtentorial in midbrain and pons = duet hemorrhages (linear or flam shaped lesions
Herniation
herniation accompanied by secondary hemorrhagic lesions
Transtentorial
midbrain and pons
Common locations for secondary herniation
linear or flame shaped lesions
Duret Hemorrhages
Subfalcine herniations
cingulate gyrus herniation
subfalcine herniation w/ infarct (black) and contusion (blue) due to trauma
Herniation
Transtentorial (uncal) herniation
see changes in their eye
Uncinate, mesial temporal:
- medial aspect of temporal lobe is compressed
- CNIII compressed
CNIII compression - pupillary dilation, impairment of ocular moments on side of lesion
Where might changes be seen in a Transtentorial herniation?
uncal herniation w/ pressure on 3rd nerve
Uncal herniation
Tonsillar Herniation
Coning
region of brain or spinal cord that lies at most distal reach of arterial blood supply.
Usually seen after hypertensive episodes
Watershed infarcts
linear or flame shaped lesions
tentorial
progression of herniation accompanied by secondary hemorrhagic lesions in midbrain and pons
Duret Hemorrhage
Duret Hemorrhage
*** on exam
Duret Hemorrhage
Duret Hemorrhage
flank shaped
involves combination of neural tissue, meninges, overlying bone and soft tissue
spina bifida
Neural tube defects
extension of CNS tissue through defect in vertebral column
myelomeningocele
only meninges protrude
miningocele
spina bifida
Myelomeningocele
reduced number of gyri in brain devo
Lissencephaly
no gyri
agyria
incomplete separation of hemispheres
holoprosencephaly
most common
Posterior Fossa Anomalies
- small posterior fossa
- misshapen midline cerebellum, vermis extends down through foramen magnum
- hydrocephalus (due to blockage)
- myelomeningocele
Arnold-Chiari malformation (chiari type II)
- less severe
Chiari Type 1
- enlarged posterior fossa
- Cerebellar vermis absent
- large midline cyst
Dandy-walker malformation **
expansion of ependyma-lined central canal of cord
Hydromyelia
fluid filled cavity in the inner portion of the cord
Syringomyelia
increased risk in premature infants, in germinal matrix
Intraparechymal hemorrhage
- infarcts in supratentorial periventricular white matter
- premature infants more susceptible
- white matter necrosis and calcification
- not a hem. but a change in the tissue itself
Periventricular leukomalacia
- extensive ischemic damage to gray and white matter
- large destructive cystic lesions
Multicystic encephalopathy
multicystic leukoencephalopathy
- losing white matter
- skull fractures
- parenchymal injury
- vascular injury
- concussion
- contusions
- lacerations
Trauma can cause:
R frontal and temporal contra-coup contusions
Old, pitted contusions
blow to surface of brain -> transmitted through skull, rapid tissue displacement, hemorrhage, edema, vascular damage
Parenchymal injury
contact between brain and skull
Coup
brain stoked opposite inner surface of skull during deceleration
Contrecoup
Contrecoup
diffuse axonal injury
Deep white matter regions are damaged by trauma
1. epidural
2. subdural
3. subarachnoid
4. intraparenchymal
4 areas of Vascular Injury
dura still attached to skull - banana shaped
slowly evolving
Venus Subdural hematoma
dural is peeled off skull, skull fracture
Arterial epidural hematom
vascular abnormalities - sudden onset of severe headache, rapid
Subarachnoid Space
Trauma - selective involvement of crests of gyri where brain may contact inner surface of skull
Intraparenchymal
centered in deep white matter, thalamus, basal ganglia, brainstem
Hypertension
normally dura fused w/ periosteum on internal skull surface
MMA vulnerable
dura separates from skull: torn vessels
smooth inner contour - compresses brain
lucid intereval - blood accumulates slowly
or rapidly
Epidural hematoma
Epidural hematoma
Subdural hematoma
Bridging veins prone to tearing
acute : venous bleeding - self limited
hematoma results - lysis, growth of fibroblasts from dural surface into hematoma, early dev of hyalinized connective tissues
Subdural hematoma
- exudate w/in leptomeninges over surface of brain
- neutrophils fill subarachnoid space
- cells infiltrate vessel walls
- complication - leptomeningeal fibrosis - hydrocephalus
Acute bacterial meningitis morphology
Pyogenic meningitis
Acute purulent meningitis
Pneumococcal Meningitis
covered in sheet of white exudate
Acute purulent meningitis
E coli meningitis
H. influenza meningitis
Leptomeningeal Pus
- absence of organisms
- viral
- self-limited, treat symptoms
Acute Aseptic Meningitis
- focal areas of necrosis w/ accompanying inflammation
- streptococci and staphylococci
- necrosis surrounded by brain swelling
- edge is granulation tissue
- can have fibrotic capsule
- tx: surgery and antibiotics
Brain Abscess
Cerebral Abscess
atherosclerosis and plaque rupture
Thrombotic occlusions are associated with?
carotid bifurcation, origin of MCA and either end of basilar artery
What are common sites of thrombotic occlusions
embolism, thrombotic occlusions associated with atherosclerosis and plaque, inflammatory processes
What is an occlusive vascular disease
- Cardiac mural thrombi most common
- thromboembolic arising in arteries
- MCA most effected by embolic infarction
- shower embolism
- embolization of bone marrow after trauma
Embolism
widespread white matter hemorrhages
embolization of bone marrow after trauma
fat embolism after fracture
shower embolization
divided into two broad gorps based on presence of hemorrhage
- nonhemorrhagic infarct
- hemorrhagic infarcts
infarcts
eventually tissue liquifies and leaves a fluid filled cavity
nonhemorrhagic infarct
like ischemic but with blood extravasation and reposition. much worse if pt on anticoagulants
hemorrhagic infarctions
...
...
lacunar infarcts, slit hemorrhages, hypertensive encephalopathy, massive intracerebral hemorrhage and hypertension to prevent dx
Effects of Hypertensive Cerebral vascular dx
1) Hypertension affects deep penetrating arteries and arterioles
- Supply basal ganglia, hemispheric white matter and brainstem
2) Vessels develop arteriolar sclerosis and become occluded
3) Devo small cavitary infarcts
Lacunar infarcts
- Rupture of small caliber penetrating vessels with small hemorrhages
- Hemorrhage resorbs leaves behind slitlike cavity surrounded by brown discoloration
Slit Hemorrhages
Hemorrhage in brain associated with neurologic symptoms - stroke
- Most common in middle to late adult life
Hypertension and cerebral amyloid angiopathy
- Most common causes
Intraparenchymal Hemorrhage
- Rupture of saccular (berry) aneurysm in a cerebral artery
- Saccular aneurysm most common type of intracranial aneurysm
- 90% at major arterial branch points in anterior circulation
- Thin-walled outpouching of vessel
- Structural abnormality
- Absence
Subarachnoid Hemorrhage
Herpes Simplex (Cowdry Type A)
Cytomegalo virus
Rabies (Negri body)
Progressive multifocal leuko-encephalopathy
Subacute sclerosing pan-encephalitis
...
Herpes Simplex virus Type 1