Notes on Traumatic Brain Injury - Key Terminology

Vocabulary flashcards covering key terms and definitions related to traumatic brain injury, its mechanisms, and hemorrhage types.

Traumatic Brain Injury (TBI)

Injury to the brain caused by external mechanical force, resulting in physical, cognitive, or consciousness changes; can be focal or diffuse and includes both primary and secondary injury.

Primary Injury

Direct mechanical disruption at the moment of impact (e.g., coup–contrecoup injury, skull fracture, initial axonal injury).

Secondary Injury

Pathophysiologic processes triggered by the primary injury occurring hours to days later (ischemia, excitotoxicity, inflammation, edema, oxidative stress) that worsen brain damage.

Diffuse Axonal Injury (DAI)

Shearing of axons due to rapid brain acceleration/deceleration; causes widespread white matter injury, often at the gray–white junction, with corpus callosum and/or midbrain involvement and prolonged coma.

Concussion

Traumatic brain function disturbance that is usually transient (<6 hours) with no gross structural brain injury.

Contusion

Focal brain hemorrhage/bruise, typically in cortical areas and at the crests of gyri.

Epidural Hematoma (EDH)

Biconvex (lens-shaped) hyperdense collection between skull and dura, commonly from rupture of the middle meningeal artery; classically with a lucid interval before rapid deterioration.

Subdural Hematoma (SDH)

Crescent-shaped hyperdense collection that crosses suture lines, due to rupture of bridging veins between dura and arachnoid; gradual onset can occur.

Parenchymal Hematoma

Bleeding within brain tissue (intraparenchymal) from rupture of small penetrating arteries, producing irregular hyperdense areas and focal deficits.

Coup-Contrecoup Injury

Brain contusions occurring at the site of impact (coup) and on the opposite side (contrecoup) due to brain movement inside the skull.

Lucid Interval

A temporary period of regained consciousness after initial loss of consciousness, classically associated with EDH.

Biconvex (Lens-shaped) Hematoma

CT appearance of an epidural hematoma; lens-shaped, does not cross sutures.

Crescent-shaped Hematoma

CT appearance of a subdural hematoma; crescent-shaped and can cross sutures.

Middle Meningeal Artery Rupture

Common arterial cause of epidural hematoma leading to rapid bleeding between skull and dura.

Bridging Veins Rupture

Venous cause of subdural hematoma from tearing of veins bridging the dura and arachnoid.

Intracranial Pressure (ICP)

Pressure inside the skull; monitored in severe TBI; elevation reduces cerebral perfusion and worsens injury.

Cerebral Edema

Brain swelling from fluid accumulation; includes cytotoxic edema (cellular) and vasogenic edema (BBB breakdown) contributing to raised ICP.

Excitotoxicity

Excessive glutamate receptor activation (e.g., NMDA) leading to excessive Ca2+ influx and neuronal injury or death.

Oxidative Stress

Imbalance between reactive oxygen/nitrogen species production and antioxidant defenses, causing lipid, protein, and DNA damage.