CNS traumatic injury Flashcards

1
Q

Concussion

A
  • A complex pathophyiosological process affecting the brain, induced by traumatic biomechanical forces
  • Rapid onset and short-term impairment of function that resolves spontaneously
  • May not loose consciousness
  • No abnormalities found on CT or MRI
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2
Q

Concussion Sx

A
  • Severity can only be determined in retrospect: after symptoms clear, after neuro exam is normal, after cognitive function returns
  • Concussion signs: poor concentration, easily distracted, ringing in ears, sadness, seeing stars, noise/light sensitivity, glassy eyes/vacant stare, vomiting and sleep disturbances
  • Sleep disturbances: hypersomnia, trouble falling asleep, restless sleep
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3
Q

Pathophysiology

A
  • Impaired neurotransmission: excessive release of glutamate leads to neurotoxicity
  • Dysregulation of ions: opening of ion channels puts strain on ion pumps and increases energy demand
  • Hypermetabolic state
  • Reduction in cerebral blood flow + hyper metabolic state results in energy crisis
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4
Q

Dx of concussion

A
  • Detailed concussion history (too many don’t report it and then return to sport prematurely- can lead to sudden death due to second impact syndrome)
  • Appearance of Sx’s might be delayed several hours following a concussive episode
  • Potential biomarkers: S100B elevates 3 hrs post trauma and clears in a week
  • SCAT imPACT BESS, eye matrix
  • Rx: none, but best is to rest brain (avoid lights, noise, stress), regular sleep pattern, meds on low doses
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5
Q

Types of injury

A
  • Abraisions: scrapping injuries to skin
  • Contusions (bruises): blood vessels rupture under intact epidermis
  • Lacerations: blunt trauma causing a tear in tissue (non-clean edges)
  • Incision: a sharp force injury w/ clean edges (longer than it is deep)
  • Stab: a sharp force injury w/ clean edges (deeper than it is long)
  • Gun shot wounds (GSW): penetrating (entrance) and may be perforating (exit)
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6
Q

Dating of contusion

A
  • Based on the color of the contusion (early-> late)
  • Red/purple, bluish brown, greenish brown, green, yellow
  • Blood products: hemoglobin, hemosiderin, biliverdin, bilirubin
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7
Q

Types of skull fractures 1

A
  • Linear: fracture often extending through entire thickness of calvarium
  • In adults is often clinically insignificant, but may cause epidural hematoma by severing the middle meningeal artery
  • In children 75% of skull fractures are linear, and complications include subgaleal hematoma (bleeding btwn aponeurosis and periosteum of skull) and epidural hematoma
  • Displaced/nondisplaced: loss of normal anatomic alignment (or not)
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8
Q

Types of skull fractures 2

A
  • Depressed: bone is pressed into cranial vault
  • Complications include post traumatic seizures, infection, loss of consciousness
  • Open/closed: absence or presence of overlying laceration
  • Complications may include communication of CSF
  • Comminuted: multiple linear fractures (from repeated blows, seen in child abuse)
  • Diastatic: separation of skull structures (can be growing fracture)
  • Hinge: skull is fractured at base and has hinge mobility
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9
Q

Basilar skull fracture

A
  • Fracture of bones of base of skull
  • Temporal bone is weak, fracture could rupture middle meningeal artery and cause epidural hematoma
  • Can produce CSF leaks (dural tearing)
  • Produces variety of effects: nausea/vomiting (brainstem), oculomotor defects (III, IV, VI), facial nerve palsies and hearing loss (VII and VIII)
  • Clinical signs: battle sign (retroauricular hematoma), raccoon eyes, rhinorrhea/otorrhea (CSF leaking out nose/ear), hemotympanicum (blood on ear drum)
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10
Q

Sites of contusion

A
  • Direct (coup) injury: at the site of impact
  • Indirect (contrecoup): opposite to site of impact
  • Can be both when there is acceleration to deceleration
  • Ex: head hitting windshield causes coup in frontal lobes then contrecoup in occipital lobes
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11
Q

Traumatic diffuse axonal injury (TDAI)

A
  • Non-traumatic causes of widespread injury to axons
  • Due to rotational acceleration/deceleration of head (shearing, twisting)
  • Usually causes unconsciousness, which may or may not be reversible
  • Damages white matter
  • Often affects corpus callosum, but can affect any structure w/ white matter
  • Gross evidence: gliding contusions, petechiae in corpus callosum, focal lesions in brain stem
  • Microscopic damage: axon spheroids (swollen damaged axons), amyloid plaques
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12
Q

Epidural hematoma

A
  • Breaking the temporal bone can tear the middle meningeal artery and cause an epidural hematoma
  • Smoothly-encapsulated hematoma that collects btwn dura and skull (calvarium)
  • Causes mass effect-> cerebral edema and/or herniation
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13
Q

Subdural hemorrhage

A
  • More common than epidural hemorrhage, due to tearing of bridging veins
  • Caused by substantial head injury
  • Usually not as smoothly encapsulated as epidural hemorrhage
  • Can form a membrane then re-bleed (usually slow bleeds)
  • Bleeds btwn dura and the arachnoid layer (into the now formed subdural space)
  • Causses mass effect-> cerebral edema and/or herniation
  • Chances are increased w/ drugs
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14
Q

Subarachnoid hemorrhage

A
  • More common than subdural and epidural
  • No mass effect
  • Other symptoms: worst headache ever, stiff neck, vomiting, deteriorating mental status, sudden death
  • Ruptured berry aneurysm, VA laceration, AVM all cause subarachnoid hemorrhage
  • Can also be caused by trauma
  • Blood in CSF causes hydrocephalus (prevents reuptake of CSF), and other vasospasms
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15
Q

Increased intracranial pressure (ICP)

A
  • Can be caused by hydrocephalus, mass effects, cerebral edema
  • 2 types of cerebral edema
  • Vasogenic edema: breakdown of BBB (tumors)
  • Cytotoxic edema: due to energy failure (infarction)
  • Cerebral edema will cause large, flat gyri, narrowing of sulci
  • ICP is what causes herniation
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16
Q

Herniation of brain structures

A
  • ICP due to mass effect causes a midline shift, which can lead to subfalcine herniation (of cingulate gyrus) in the frontal lobe, medial temporal lobe (uncal) herniation thru the tentorium (pushes on the brainstem/cerebellum)
  • Uncal herniation compresses ipsilateral III, contralateral crus cerebri
  • Eventually can also get a cerebellar peduncle herniating thru the tentorium, and a cerebellar tonsil herniation thru foramen magnum
  • Duret hemorrhage: midbrain herniation that occludes vessels feeding the midbrain, then reperfusion of the midbrain causes damage (is a reperfusion injury)
  • Bilateral transtentorial herniation: due to swelling of brain
  • Tonsilar herniation: cerebellar tonsils thru foramen magnum