Neuroscience Week 6: CNS Trauma Flashcards
Traumatic parenchymal injuries
3 listed
- Concussion
- Contusion
- Diffuse axonal injury
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Concussion description
Transient neurologic dysfunction (with or without loss of consciousness, transient respiratory arrest, loss of reflexes)
Repeated concussions can result in?
Repeated episodes can result in chronic traumatic encephalopathy (with cognitive impairment, Parkinsonism)
Contusion description
caused by rapid tissue displacement, disruption of vasculature, with subsequent hemorrhage, tissue injury and edema. Coup and contrecoup are the most common types.
Contusion types
2 listed
- Coups
- Contrecoup
Coup contusion
contusion that occurs at the point of impact
Contrecoup contusion
contusion that occurs opposite the point of impact
Contusion common location
involving the crest of the gyri in regions overlying rough and irregular inner skull surfaces (e.g. orbitofrontal and temporal lope tips)
Identify
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Contusions histology
- perivascular petechial hemorrhages with red neuron cell changes
- Neutrophils infiltrate within 2 hours
- Macrophages infiltrate at approximately 48 hours
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Diffuse axonal injury: adults common causes
due to high velocity accidents (motor vehicle collisions, falling from a building)
Diffuse axonal injury: Infants common causes
Can be due to homicidal head injuries (so-called shaken baby syndrome)
Diffuse axonal injury trauma type
Due to rotational acceleration deceleration injuries
Diffuse axonal injury location
Affects the white matter tracts of the brain and brainstem (corpus callosum, internal capsule, parasagittal white matter, cerebral peduncles of the mid brain, cervico medullary junction, etc)
Diffuse axonal injury histology
- axonal spheroids
- Amyloid precursor protein immunostain demonstrating axonal spheroids
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Diffuse axonal injury symptoms
Immediate loss of consciousness
Diffuse axonal injury overview
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Epidural hematoma common causes
Accidental falls are the leading cause > traffic accidents > assaults
Epidural hematoma etiology
- Result from laceration of the dural arteries (classically the middle meningeal artery) with rapid accumulation of blood in minutes-to-hours
- There is usually an associated temporal skull fracture
Epidural hematoma Treatment
Epidural hematomas are neurosurgical emergencies and if not evacuated may lead to herniation and death
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Epidural hematoma lucid interval
There is a ‘lucid’ interval in 1/3 of the cases (“talk and die”; more common in pediatric population)
Epidural hematoma trauma type
Epidural hematomas are more commonly associated with impact rather than acceleration-deceleration type incidents
Epidural hematoma overview
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Subdural Hematoma origin
have venous origin resulting in slower accumulation of blood (hours-to-days, to even weeks)
Subdural Hematoma Etiology & risk
- result from rupture of bridging (between dural sinuses and cortical vessels) veins in the subdural space
- more common in patietns with reduced brain volume (elderly, alcohol use disorder) or infants (who have thin-walled bridging veins)
Subdural Hematoma Trauma type
- common with acceleration-deceleration type incidents
- Manifest within 48 hrs of injury with headache, confusion and progressive neurological deterioration
Subdural Hematoma size of hemorrhage
- These hemorrhages range in size from just a film of blood to large life-threatening masses
- May be bilateral
Chronic Subdural Hematoma
As the hemorrhages resolve they become organized by granulation tissue and fibrosis, forming a cavity which may re-bleed, resulting in a chronic subdural hematoma
Subdural Hematoma Prognosis
- Most subdural hemorrhages, however, resolve to a thin, hemosiderin-stained fibrous membrane as the blood products are resorbed
- Accumulation may be delayed
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Subdural Hematoma Overview
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Traumatic vascular injury
- Epidural hematoma
- subdural hematoma
Herniations
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Herniation syndromes
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Subfalcine herniation
- when the cingulate gyrus herniates underneath the dural falx, which can compromise ACA blood flow
- This represents a space-occupying lesion on the right hemisphere (for example, right sided subdural hematoma)
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Tentorial (Uncal) Herniation description
- involves the medial aspect of the temporal lobe herniating across the tentorium cerebelli
- may damage ipsilateral oculomotor nerve
- may occlude the posterior cerebral artery
Tentorial (Uncal) Herniation Clinical presentation
- Dilated pupil
- down and out pupil
- weakness on the contralateral side
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Tentorial (Uncal) Herniation Massive herniation
- a Massive herniation may push the contralateral cerebral peduncle against the tentorium cerebelli (Kernohan’s notch)
- resulting in ipsilateral weakness
Duret Hemorrhage
- Caudal displacement and elongation of brainstem congestion and rupture of the paramedian pontine branches of the basilar artery or penetrating veins and arteries supplying the midbrain
- Causes linear or flameshaped hemorrhages in midbrain and pons
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Tonsilar herniation description
- occludes the foramen magnum with the tonsils of the cerebellum
- results in CSF blockage
- Medullary ischemia and cardiorespiratory collapse
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Identify
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