Trauma to the Nervous System Flashcards
A more diffuse force applied to the skull typically produces a ___ skull fracture, while a more local or localized force causes a ___ skull fracture.
Linear; depressed
A severe skull fracture may be associated with an underlying ___ of the brain.
Contusion or laceration
Fractures at the skull base, face, or orbit can entrap or compress ___.
Cranial nerves
Rx skull fracture?
Surgical removal of bone fragments and debris, closure of any dural tears
What are brain contusions?
Superficial hemorrhages at the tops of cortical gyri near the point of impact (coup) or more remotely in the brain (contrecoup) from movements of the brain within the skull
Most common locations of brain contusions?
Basal or ventral surfaces of the frontal and anterior temporal lobes, where the bony skull is roughened or protuberant
What types of acceleration injuries cause brain contusions?
Angular or rotation, not linear
What is cerebral autoregulation?
Vasoconstriction or vasodilation to preserve optimal cerebral blood flow despite fluctuation in system BP over a range of 60-140 mm Hg (MAP)
In the setting of severely increased ICP, Cushing’s response may be observed - what happens?
Elevation of systemic BP to preserve cerebral blood flow + bradycardia and slowed RR
Types of herniation that can occur with increased ICP?
- Subfalcine -> cingulate gyrus pushed under the falx cerebri
- Uncal -> medial temporal lobe compressed against the midbrain
- Tonsillar -> shifting of lower brain stem and cerebellar tonsils down the foramen magnum
Which type of herniation causes a fixed and dilated ipsilateral pupil?
Uncal herniation
An acute subdural hematoma occurs after the focal laceration of ___, which empty into larger venous sinuses of the brain.
Bridging cortical veins
R acute subdural?
Surgical removal of the hematoma if indicated
Cause of epidural hematoma?
Rupture of meningeal artery or vein, often from a temporal bone fracture
Three components of intracranial volume?
Brain
Vascular
CSF
Why does mechanical hyperventilation decrease ICP?
Reduces arterial pCO2 -> cerebral arterial vasoconstriction -> reduced intracranial blood volume -> reduced ICP
Calculate GCS?
Eye opening: 1-4 -> none, to pain, to verbal command, spontaneously
Motor response: 1-6 -> none, abnormal extension (decerebrate rigidity), abnormal flexion (decorticate rigidity) -> withdraws from pain (flexion) -> localizes pain -> obeys verbal commands
Verbal response: 1-5 -> no response, makes incomprehensible sounds -> uses inappropriate words -> disoriented and converses -> oriented and converses
Presentation of a high cervical spinal cord lesion?
Quadriplegia with respiratory paralysis (if C3-C5 are involved) +/- sympathetic involvement (bradycardia, fluctuating BP, hypothermia)
Cause and presentation of central cervical cord syndrome?
Elderly patients with advanced degenerative arthritis of the spinal colum who fall forward and hyperextend the neck -> central hemorrhage of cervical SC -> predominant weakness of the upper limbs (medial CST and cervical anterior horn cells)
Neurological recovery is more likely if ___ are begun within 8 hours of spinal cord injury.
High-dose IV corticosteroids (dexamethasone)