Head injuries Flashcards
(33 cards)
why aren’t more adults susceptible to damage similar to shaken baby syndrome?
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
what characterizes a subgaleal hematoma?
this hemorrhage is found beneath the galea aponeurotica (directly below the scalp) and is not obvious externally
what characterizes terminal fall injuries?
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
what characterizes cerebral contusions
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)
what does a series of oval to round contusions on a pt raise suspicion of?
punch
what characterizes transtentorial/uncal herniation?
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.
what is a bite mark to the tongue indicative (but not diagnostic) of?
seizure
what characterizes subarachnoid hemorrhage (SAH)?
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
what characterizes diffuse axonal injury?
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.
what can cause periorbital contusions (racoon’s eyes/spectacle hematomas)?
gunshot wound to the head (may generate enough force to fracture the orbital plates)
what are the 2 kinds of cerebral edema? what morphology is associated w/it?
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
what are the categories of soft tissue injury to the head?
subgaleal hematoma
epidural
subdural
subarachnoid hemorrhage
What is epidural hematoma?
above dura - typically associated w/a fracture of the temporal bone = middle meningeal artery damage
What is subdural hematoma?
below dura - not usually associated w/a fracture, due to tearing of bridging veins - may not require tx
Causes of subarachnoid hemorrhage?
ruptured berry aneurysm cerebral contusion (coup and countercoup injuries)
what is a lefort I fracture?
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
what characterizes subdural hematoma?
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.
what is the worst result of cerebral edema?
herniation, which is due to increased ICP
are skull fractures common in children?
no - their skulls tend to be more pliable
what is the spectrum of diffuse traumatic brain injury?
concussion (functional damage w/o structural damage) and diffuse axonal injury (aka DAI = structural damage)
what is shaken baby syndrome?
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
what characterizes tonsillar herniation?
the posterior medial portion of the cerebellum is forced through the foramen magnum
what is a gliding contusion?
this is when gliding of the brain under the dura leads to diffuse axonal injury (DAI)
what are the different types of skull fracture?
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)
