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head trauma path
CBN
30
Medical
Graduate
01/04/2011

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Cards

Term
what does a series of oval to round contusions on a pt raise suspicion of?
Definition
a punch
Term
what is a laceration?
Definition
a wound due to a blunt object tearing soft tissue (not a cut wound)
Term
what can cause periorbital contusions (racoon's eyes/spectacle hematomas)?
Definition
gunshot wound to the head (may generate enough force to fracture the orbital plates)
Term
what characterizes terminal fall injuries?
Definition
these are often due to loss of consciousness and consist of injuries to the bony prominences of the face - often in *linear distribution. terminal fall injuries may include abrasions, contusions, and lacerations
Term
what are the categories of facial fracture?
Definition
dentoalveolar, lefort I-III and sagittal - all of which require a lot of force (not generally produced in a simple fall).
Term
what is a dentoalveolar fracture?
Definition
separation of a *fragment of the mandible due to anterior or lateral direct force*. the fragment often contains a number of fractures.
Term
what is a lefort I fracture?
Definition
a transverse fracture of the maxilla, above the apices of the teeth and through the nasal septum, maxillary sinuses, and palantine bone of the sphenoid bone
Term
what is a lefort II fracture?
Definition
a *pyramidal fracture w/a similar posterior path as a lefort I - however, lefort II fractures also curve anteriorly near the zygomatic-maxillary structure and pass through the inferior orbital rim into the orbital floor and through the medial orbital wall and across the nasal bones and septum.
Term
what is a lefort III fracture?
Definition
this is a high transverse fracture involving the maxilla. lefort III fractures pass through the nasofrontal suture, through the medial orbital wall and frontozygomatic suture before passing through the sphenoid bone.
Term
what is a sagittal fracture?
Definition
a fracture running in the sagittal plane which passes through the maxilla
Term
what are the different types of skull fracture?
Definition
linear (usually due to a simple fall), depressed (fragments into brain), diastatic (sawtooth appearance, younger person - brain swells and pushes out sutures), basilar (*battle sign* - contusion behind the ear), orbital roof (periorbital ecchymosis - either due to direct or penetrating injury), hinge (usually fatal - fracture going through one side of the skull to the other), and ring (around foramen magnum - spine is pushed up through by upward force from below)
Term
are skull fractures common in children?
Definition
no - their skulls tend to be more pliable
Term
what are the categories of soft tissue injury to the head?
Definition
subgaleal hematoma (directly under the scalp - not usually externally visible), epidural hematoma (above - typically associated w/a fracture of the temporal bone = middle meningeal artery damage), subdural hematoma (below - not usually associated w/a fracture, due to tearing of bridging veins - may not require tx), subarachnoid hemorrhage (harder to remove, not usually due to trauma - usually due to vascular problems such as a ruptured berry aneurysm), and cerebral contusion (coup: injury at site of impact, head is usually stationary or contra coup: injury on opposite side of head, head is moving).
Term
what characterizes a subgaleal hematoma?
Definition
this hemorrhage is found beneath the galea aponeurotica (directly below the scalp) and is not obvious externally
Term
what characterizes an epidural hematoma (EDH)?
Definition
these often involve the lateral temporal and sphenoid bones which the *meningeal arteries are near and present on the surface of the dura. epidural hematomas cause a *linear flattening of the cortex (shelf-like). artifactual EDH may occur in cases like a fire where increased vapor pressure fractures the skull and heated bone marrow moves to the superior surface of the brain. posterior fossa EDH is rare. EDH can be an important tox specimen (b/c it has been sequestered).
Term
what characterizes a subdural hematoma (SDH)?
Definition
this is due to tears of bridging veins which link superficial cortical veins to the superior sagittal sinus (though occasionally arteries are involved) and result in compression of gyri and sulci = undulating surface of the cortex (unlike the flattened surface seen in EDH). skull fractures may or may not be present (damage is simply due to movement of the brain inside the skull). SDH's are good tox specimens. over time chronic SDH may produce a flattened cortex similar to EDH, initially w/an inner arachnoid side membrane + outer dural side membrane - eventually becoming a single fibrous membrane.
Term
what characterizes subarachnoid hemorrhage (SAH)?
Definition
this hemorrhage occurs between the arachnoid layer and the cerebral cortex. this may occur due to trauma (vertebral artery trauma = basal SAH) or naturally (berry aneurysm, AVM, cocaine, meth). they are not easily wiped off the cortical surface
Term
what characterizes cerebral contusions?
Definition
these appear as a linear streak-like hemorrhage of the cortex and may be due to: coup (stationary head, moving object = wound at impact), contra coup (moving head, stationary object = wound opposite impact), intermediary coup (rotational movement due to battering of head = brain damage due to its own uneven movement), fracture or herniation (w/brain swelling around a falx).
Term
what is a bite mark to the tongue indicative (but not diagnostic) of?
Definition
a seizure
Term
what is the spectrum of diffuse traumatic brain injury?
Definition
concussion (functional damage w/o structural damage) and diffuse axonal injury (aka DAI = structural damage)
Term
what characterizes diffuse axonal injury?
Definition
this due to rapid brain acceleration/deceleration is seen in white matter tracts (corpus callosum, internal capsule, cerebral peduncles) which have a high density of axons. this is most severe in midline and paramidline structures (prone to shearing force). microscopically DAI consists of axonal swelling, disruption of cytoarchitecture/neurofilaments (axonal bulbs), and can be stained for w/beta amyloid precursor protein in as little as 2-3 hours.
Term
what is a gliding contusion?
Definition
this is when gliding of the brain under the dura leads to diffuse axonal injury (DAI)
Term
what is shaken baby syndrome?
Definition
this is due to rapid acceleration/deceleration of the brain and may not involve distinct impact sites. sub dural hematoma (torn veins), brain swelling, cervical cord injury (RAS etc), retinal/optical nerve injury (retinal hemorrhages are red flags for abuse), possible gripping injury are all associated w/shaken baby syndrome. "respirator brain" is commonly seen in shaken baby syndrome as the brain swelling causes diffuse ischemia, which leads to further swelling, etc = brain starts to fall apart.
Term
why aren't more adults susceptible to damage similar to shaken baby syndrome?
Definition
babies have a large head relative to their body, weak cervical musculature, poor control of their head/neck, the cervical cord is different, babies have a higher brain water content, and babies only have a minor degree of myelination.
Term
what are the 2 kinds of cerebral edema? what morphology is associated w/it?
Definition
1) vasogenic: integrity of the BBB is disrupted, causing *interstitial edema. 2) cytotoxic edema: increase in *intracellular fluid from hypoxic-ischemic insult. morphology: gyri flattened, sulci narrowed.
Term
what is the worst result of cerebral edema?
Definition
herniation, which is due to increased ICP
Term
what characterizes cingulate gyrus herniation?
Definition
unilateral asymmetric expansion of the cerebral hemisphere displaces the cingulate gyrus under the falx cerebri
Term
what characterizes transtentorial/uncal herniation?
Definition
the medial aspect of the temporal lobe becomes compressed against the tentorium, compressing the 3rd nerve = pupillary dilation on the ipsilateral side of the lesion.
Term
what characterizes tonsillar herniation?
Definition
the posterior medial portion of the cerebellum is forced through the foramen magnum
Term
what characterizes the morphology of hypoxia/ischemia in the brain?
Definition
immediately after insult, the brain may appear normal - but w/in 24-48 hrs, the brain becomes swollen and necrosis may develop = respirator brain
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