CNS Trauma Flashcards
What percent of head-injury deaths occur prior to hospitalization?
66% (thus, primary-prevention measures are crucial)
Trauma is the leading cause of death up to age _________.
45
What are the four categories of cerebral injury given in this PowerPoint?
- Ischemic/hypoxic
- Contact phenomenon (getting hit with something)
- Penetrating head trauma (GSW, stabbing)
- Accelerational (falling, stopping suddenly)
Describe the four types of skull fractures.
Linear: a crack in the skull
Depressed: indentations
Basilar: anything affecting the base of the skull
Growing: an indentation followed by “popping” back out and resorbing
Which kind of cranial fracture is associated with CSF leak?
Basilar – gravity pulls the CSF down, leading to leakages
Diagnosis of basilar skull fractures is done predominantly by ___________.
clinical features –the convoluted base of the skull is difficult to detect fractures on
What symptoms suggest basilar skull fractures?
CSF rhinorrhea or otorrhea Racoon eyes Subconjunctival hemorrhage Battle's sign (a late-appearing ecchymosis posterior to the ear) Facial nerve palsy Bleeding from external auditory meatus
What kind of hematoma is often associated with skull fractures?
Epidural
The lucid interval is characteristic of _________ hematomas.
epidural (symptoms appear later, like an EPilogue appears later in a book)
Epidurals occur when the ______________ is ruptured (blood vessel).
middle meningeal (frequently from skull fractures cutting the artery)
What blood vessels tear in subdural hematomas?
The superficial cerebral veins
What kind of injury leads to subdural hematomas?
Rapid translational injuries (e.g., stopping suddenly or being shaken); think of the reason: your brain moves suddenly and stretches the veins that connect the brain to the dura
Describe the shape of the blood (appearing on CTs) for epidural and subdural hematomas.
Epidural = lentiform, because the dura prevents it from spreading into the parenchyma Subdural = crescent
What is one reason that subdural hematomas typically have a poorer outcome than epidural hematomas?
Subdural hematomas require a more traumatic injury that will often cause brain contusions; the increased intracranial pressure from the bleeding is added to the intracranial pressure from the bruise’s inflammation.
Rotational injuries lead to damage that requires _________ to notice.
microscopic examination
What histologic finding is characteristic of rotational injury?
Axonal spheroids (retraction balls of Cajal) 24 hours after injury
What parts of the brain are most commonly the sites of axonal spheroids?
The corpus callosum and brainstem
The brain accommodates to ________ increases in pressure.
long-lasting (that is, the brain does not compress to acute changes in pressure)
Intracranial compensation occurs by decreasing what two fluids?
Venous blood and CSF
Once the compensations of the venous blood and CSF are exhausted, __________ occurs.
rapid increase in ICP
What is the most dire sequela of uncal herniation?
The pressure put on the brainstem – the midbrain in particular
Transtentorial herniation often presents with ____________.
contralateral hemiparesis and ipsilateral mydriasis (a “blown pupil,” per Dr. Ojemann) due to compression of the corticospinal tract and oculomotor nerve (which carries the parasympathetic input to the pupillary constrictor)
Central herniation can be very serious. What structure herniates in this condition and why is that a big problem?
The thalamus pushes over –into the third ventricle – and pushes down onto the brainstem.
Why does traumatic brain injury lead to increase in cerebral blood flow?
The mechanical damage (such as pressure or acceleration) leads to widespread release of neurotransmitter; the excess activity leads to astrocyte-mediated vasodilation.
