TBI: Introductory Information - NeuroRehab I Flashcards

This set covers definitions, mechanisms of injury, monitoring parameters, surgical interventions, herniation syndromes, and classification/prognostic tools for Traumatic Brain Injury (TBI).

Traumatic Brain Injury (TBI)

An insult or injury caused by an external force that may produce an altered or diminished state of consciousness and/or which results in impairment of cognitive abilities and or physical function.

Coup Injury

Caused when the head is stopped suddenly and the brain rushes forward, sustaining injury by hitting the side of the skull and rubbing against inner ridges.

Contrecoup Injury

Caused when the brain bounces off the primary surface and impacts against the opposing side of the skull, resulting in additional injury as the brain rubs against inner ridges.

Primary Injury

Tissue damage that occurs at the site of the accident, including skull fractures, contusions, lacerations, intracranial lesions, and Diffuse Axonal Injury (DAI).

Secondary Injury

Damage that occurs after initial onset as a direct result of the primary injury, such as increased ICP leading to ischemia, hypoxia, herniation, and mass effect.

Diffuse Axonal Injury (DAI)

A primary injury caused by rapid acceleration/deceleration forces resulting in axonal cytoskeleton disruption and impaired axonal transport.

Autoregulation

Changes to the diameter of the vasculature to alter cerebral blood flow to maintain homeostasis in response to changes in $PaO_2$, $PaCO_2$, ICP, and MAP.

Intracranial Pressure (ICP)

The pressure inside the skull, which normally monitors at a value of $<20$,$\text{cmH}_2\text{O}$.

Cerebral Perfusion Pressure (CPP)

Calculated as $CPP = MAP - ICP$; it must be maintained at $>50$,$\text{mmHg}$ to prevent hypoxia.

Craniotomy

A surgical procedure where a small section of the skull (bone flap) is removed to clean out a hematoma and then replaced after surgery.

Craniectomy

A surgical procedure where a section of the skull is removed for a period of time to allow swelling to occur with decreased pressure from the skull.

Subfalcine Herniation

A syndrome where the cingulate gyrus is pushed under the falx cerebri; it often presents without symptoms unless the Anterior Cerebral Artery (ACA) is occluded.

Central Herniation

Downward displacement of the brainstem; mild cases stretch CN VI (Abducens) causing lateral rectus palsy; severe cases can lead to tonsillar herniation through the foramen magnum.

Transtentorial (Uncal) Herniation

A syndrome characterized by the clinical triad of a blown pupil (ipsilateral CN III), hemiplegia (usually contralateral), and coma due to distortion of the midbrain reticular formation.

Kernohan’s phenomenon

Ipsilateral hemiplegia occurring when a transtentorial herniation causes significant compression of the medulla.

Heterotopic Ossification

A common secondary impairment following TBI involving the formation of bone in abnormal locations, typically in soft tissues.

Dysatunomia

A common primary impairment following TBI involving dysfunction of the autonomic nervous system.

Mannitol and Barbiturates

Pharmacological agents used to reduce ICP and manage seizures in acute TBI management.

Mild TBI

Classified by Loss of Consciousness (LOC) of $0-30$,$\text{min}$, Altered State of Consciousness (AOC) that is brief and $<24$,$\text{hrs}$, Post-Traumatic Amnesia (PTA) of $0-1$,$\text{day}$, and a GCS score of $13-15$.

Moderate TBI

Classified by LOC of $30$,$\text{min}$ to $24$,$\text{hrs}$, AOC of $>24$,$\text{hr}$, PTA of $1-7$,$\text{days}$, and a GCS score of $9-12$.

Severe TBI

Classified by LOC of $>24$,$\text{hrs}$, AOC of $>24$,$\text{hr}$, PTA of $>7$,$\text{days}$, and a GCS score of $<9$.

Post-traumatic Amnesia (PTA)

The length of time between the injury and the point at which the patient can remember ongoing events and maintains orientation to person, place, time, and situation.

Galveston Orientation and Amnesia Test (GOAT)

A series of 10 questions regarding person, place, time, situation, and memory before/after injury, where a score of $76-100$ is considered normal.

Coma Recovery Scale (CRS)

A 23-item assessment with six subscales (Auditory, Visual, Motor, Oromotor, Communication, Arousal) that detects mild changes early in recovery to predict functional outcome.