Neurocritical care topics are covered frequently on the neurology Board and RITE* exams. Your expected knowledge of these topics, however, is less in-depth than other neurology topics. Here, we will cover the high-yield neurocritical care topics covered on these exams.
Author: Steven Gangloff, MD
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Table of Contents
Disorders of Consciousness
- Arousal is primarily governed by the ascending reticular activating system (ASAS) located in the pons and midbrain tegmentum.
- The ASAS has output to the reticular nucleus of the thalamus.
Definitions of states of consciousness
- Drowsy: arousable with mild stimuli
- Stupor: arousable only to vigorous stimulation
- Coma: not able to be aroused.
- Delirium: waxing and waning consciousness, with impaired attention.
- Unresponsive wakefulness: Formerly known as “persistent vegetative state.” Unresponsive to stimulation, but with the return of sleep-wake cycles and autonomic maintenance.
- The word “obtunded” is poorly defined and should be avoided.
- Pupillary: CN II (afferent) → CN III (efferent)
- Oculocephalic: CN VIII (afferent) → CNs. III, IV, VI (efferent)
- Caloric: CN VIII (afferent) → CNs. III, IV, VI (efferent)
- Corneal: CN V1 (afferent) → VII (efferent)
- Gag: CN IX (afferent) → CNs IX & X (efferent)
Traumatic Brain Injury (TBI)
Diffuse axonal injury
- Due to shearing forces from extreme acceleration and deceleration.
- A biopsy will have swollen proximal ends of axons in the appearance of bulbs known as “retraction balls.” Punctate hemorrhages may also be seen.
Basilar skull fracture
- Battle’s sign (ecchymosis of the mastoid region) and raccoon eyes (periorbital ecchymosis) may be seen.
- May also have leakage of CSF from the ears (otorrhea) or nose (rhinorrhea).
- Can test rhinorrhea or otorrhea for β-transferrin, to determine if a CSF leak is present, as this is only positive in CSF.
Non-accidental trauma in a child
- Suspicious signs include spiral fracture of the humerus, immersion burns, rib fractures, retinal hemorrhages (from shaking), long bone injuries, duodenal hematomas, focal brain contusion, subdural hematoma or skull fracture.
Spinal Cord Trauma
- For information on spinal cord anatomy and localization of lesions, see our Spinal Cord chapter.
- Disruption of autonomic sympathetic function causes unopposed parasympathetic activity, which presents with bradycardia and hypothermia.
- Caused by lesions in the spinal cord above T6. Can treat with α-agonist and β-agonist medications.
- The major causes of death after spinal trauma are spinal shock and aspiration.
- Hypothermia and corticosteroids can be considered.