TBI & Dementia Flashcards
_____ is the number one risk factor for development of dementia
Traumatic brain injury
(TBI = 5-15% of dementia, even one concussion increases risk)
Define diffuse axonal injury
Widespread injury to axons secondary to traumatic brain injury
Diffuse axonal injury is caused by a______
shearing of axons
Diffuse axonal injury results in neuronal dysfunction by disruption of _____ (2).
- Axonal plasma membranes (dysreg. of ionflex)
- Cytoskeleton (defective axonal transport)
Historical findings of diffuse axonal injury
Axonal swelling at sites of injury →Tearing of axons → bulbs or spheroids develop → proximal portion is retracted towards body → axonal retraction spheroids→ Wallerian degeneration: lost forever
Diagnosis of diffuse axonal injury (2)
- Immunostains for APP
- Silver stains confirm diagnosis
Diffuse axonal injury
(stain for APP- Brown precipitate)
Routine H&E section from a patient w/ DAI.
(note: there are scattered axonal retraction spheroids/bulbs/balls. Black arrows are pointing at several good examples).
Silver stains from a patient with DAI.
(scattered axonal retraction spheroids, which stain black on silver stains. Images to right: high power views also exhibiting axonal retraction spheroids (white arrows).
A concussion is a _____ that results in sudden onset of ______.
- mild traumatic brain injury
- transient neurological dysfunction
(Common in: bycles or car accident, falls, sports injuries, exposure to explosion)
Concussion: signs and symptoms
- Headache
- Loss of consciousness
- Amnesia
- Cognitive impairment: confusion, slowed rxn times
- Behavioral changes
- Sleep disturbance
Concussion: pathogenesis
Diffuse axonal injury
Symptoms of a concussion generally resolved within ___.
3 weeks
(if an athlete returns before they are fully recovered they could develop a secondary concussion)
_______ (diagnostic) can visualize diffuse axonal injury.
Diffusion Tensor MRI
(regular CT & MRI will come back normal)
Multiple concussions will increase the risk of developing (3)
- Depression
- Dementia
- Parkinsonism
(chronic traumatic encephalopathy)
What causes a cerebral contusion?
Blow To The Head resulting in abrupt acceleration / deceleration of the brain
(worse than concussion)
Define coup versus counter-coup cerebral contusion
- Coup: contusion occurs at the point of impact
- Counter-coup: contusion occurs opposite the point of impact (180 degrees)
(it is possible to have both if the head as mobile)
_______ (Coup/contre-coup) injuries occur when the head is stationary and stuck by an object (i.e. Hit by a baseball bat)
Coup
______(Coup/contre-coup) injuries occur when the head is in motion and abruptly stops (i.e. falls of a ladder).
Contrecoup
Cerebral contusion: Most common area(s) of the brain
- Frontal
- temporal
Early histologic findings of a cerebral contusion
- Edema and Hemorrhage and cortex
- Neuronal injury in cortex buy 24 hours (Red neuron changes)
- Infiltrates of neutrophils than macrophages
Later histologic findings of a cerebral contusion
- Gliosis with hemosiderin-laden macrophages
- Cavitary lesion (empty cystic cavity)
(image to the right: yello/brown is from the hemosiderin)
Epidural hematomas are due to _____
- arterial bleeding
- Skull fracture → middle meningeal artery tear
- Blood collects between the skull and dura
If an epidural hematoma is not repaired, what may result?
A transtentorial, uncal herniation may occur→ midbrain hemorrhage→ death
“lucid interval”
After a blow to the head, a period of unimpaired consciousness for several hours while epidural blood accumulates under arterial pressure (20-50% of pts)
(Up to 1/3 of patients who develop an epidural hematoma do not lose consciousness at the time of the precipitating head injury)
Subdural hematoma: causes
- Venous bleeding from torn bridging veins which course from the brain to the dural venous sinuses
- Blood collects between the dura and the arachnoid
Subdural hematomas are bilateral in 15%–20% of cases, and these may impair ______.
cognitive function and lead to a mistaken diagnosis of dementia
“Organization” of a subdural hematoma
Fibroblasts and blood vessels from the dura grow into the underlying hematoma (granulation tissue) → lay down collagen→ mature fibroconnective tissue→ retracts→no compression
(this can still bleed again from minor injury → transtentorial herniation → death)
Patient population at a greater risk for a subdural hematoma from minor trauma
- Elderly
- Alcoholics
- Dementics
(smaller atrophic brains)
Traumatic subarachnoid hemorrhage
Traumatic rupture small vessels in subarachnoid space
Potential complications of a traumatic subarachnoid hemorrhage (2)
- Vasospasm→ ischemia (days later)
- Hydrocephalus (communicating)
Pathophysiology of communicating hydrocephalus post-traumatic subarachnoid hemorrhage
after subarachnoid hemorrhage heals→ fibrosis of the meninges can obliterate the arachnoid granulations→ interfering with resorption of CSF
Traumatic intraparenchymal hemorrhage
Rupture of small vessels within the brain parenchyma
Traumatic intraparenchymal hemorrhage: potential complication
herniation
