Week 6: Pathology of trauma and increased intracranial pressure, and TBI Flashcards
Define the four basic classification of traumatic injury and describe and define the components.
- Blunt force injuries:
- abrasions: scrapping injuries
- contusions: blood vessels ruptured under intact skin (bruise)
- lacerations: crushed wound edges and tissue bridging - Sharp Force injuries:
- incised wounds: clean division of skin and subQ
- stab wounds
- chopping wounds - Projectile Injuries
- handgun, shotgun, rifles,
- arrows - Thermal, electrical, chemical, other
Describe the color of the skin changes seen in contusions and the name the red blood cell breakdown product that corresponds to the skin color.
- red/purple: hemoglobin
- bluish brown: hemosiderin
- greenish brown: hemosiderin/biliverdin
- green: biliverdin/bilirubin
- yellow: bilirubin
List and define the 7 types of skull fractures.
- linear: fracture often extending through entire thickness of calvarium
- displaced/nondisplaced: loss of normal anatomic alignment
- impacted: ends of bones crushed together
- distracted-pulled apart - Depressed: bone is pressed into cranial vault
- Open/closed (compound/simple): absence/presence of overlying laceration. Open to CSF.
- comminuted: multiple linear fractures
- Diastatic: separation of skull sutures
- hinge: skull is fractured at base and has hinge like mobility
Name some of the sequelae of traumatic brain injury.
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Define herniation.
-protrusion of an organ through the structure that normally contains it
List the four major types of brain herniation. For each indicate the direction of forces leading to the herniation, the structures through which the herniated tissue moves, with the resulting complication.
- subfalcine herniation: herniation of cingulate gyrus underneath the falx
- mass lesion in one hemisphere produces ipsilateral herniation - unilateral transtentorial herniation
- cause: space occupying lesion in one hemisphere
- herniation of medial temporal lobe through tenurial hiatus
- compression of CN3 (ipsilateral), contralateral cerebral peduncle, PCA - Bilateral transtentorial herniation
- diffuse symmetrical swelling of the brain
- same as #2 but bilateral - Tonsilar herniation
- increased intracranial pressure above the tentorium - external herniation: herniation through a surgical defect in the skull
Name three common causes of increased intracranial pressure sufficient to result in herniation.
- hydrocephalus
- space occupying lesion (tumor, epidural/subdural hematoma, brain hemorrhage)
- cerebral edema
Define Duret hemorrhages and identify their common location.
-hemorrhages in the midbrain and pons
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Provide a reason why tonsillar herniation is so dangerous.
-increased intracranial pressure above the tentorium
Describe the gross and microscopic appearance of a recent and remote contusion.
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Describe the typical location of “coup” and “contrecoup” contusions.
- coup=direct blow to the surface of the brain. Location is at the site of impact
- contrecoup=indirect, opposite of the site of impact. Brain can bang back and forth in CSF, and after crashing into the skull, the brain may rebound and impact into the inside surface of the skull
- common sites: temporal tips and inferior aspect of frontal lobes
Define traumatic diffuse axonal injury and state the type of injury after which it occurs.
- non-traumatic causes of widespread injury to axons
- often involved with acceleration and deceleration of the head
- individuals with TDAI usually unconscious from time of injury and may remain unconscious
- think white matter, areas affected may include corpus callosum, dorsolateral quadrants of the rostral brain stem
Describe the gross appearance of an epidural hematoma.
-blood collected outside the dura
Describe the gross appearance of a subdural hematoma.
-underneath dura, more diffuse over the brain
Name three conditions that increase the chances of a subdural hematoma.
- more common at extremes of life: children and elderly
- caused by substantial head injury
- mechanical causes: shearing stress tearing bridging veins, change in velocity of head,
