What causes cerebral ischemia or hypoxia in TBI?

• A. Compression or rupture of blood vessels
• B. Increased neural activity
• C. Immune reaction
• D. Spinal injury

Answer: (A)

In brain injury, ischemia or hypoxia mainly results when the brain’s blood supply is disrupted by damage to the blood vessels themselves. Compression or rupture of cerebral vessels narrows or tears arteries and veins, so oxygenated blood can’t reach brain tissue adequately. That drop in blood flow directly causes oxygen deprivation and energy failure in neurons, which drives secondary injury processes.

Keep in mind that other factors can worsen blood flow later. Swelling inside the skull can push on vessels and raise intracranial pressure, lowering cerebral perfusion pressure and further reducing flow. Increased neural activity would raise the brain’s oxygen demand rather than create a shortage of supply. An immune reaction can contribute to inflammation and edema, which worsens perfusion, but the immediate cause of ischemia is the disruption of the vessel itself. Spinal injury doesn’t directly affect cerebral blood flow to cause brain ischemia.