Which statement accurately describes the most common causes of secondary brain injury?

• A. Occurs immediately after impact
• B. Hypoxia and hypotension are major causes
• C. Edema is a primary brain injury
• D. Results from direct brain trauma only

Answer: (B)

Secondary brain injury is the cascade of processes that worsen brain damage after the initial trauma. The most common culprits are hypoxia and hypotension because when oxygen delivery or cerebral perfusion drops, neurons that survived the primary insult can still die from ischemia. Keeping the airway open, ensuring adequate breathing, and maintaining adequate blood pressure are crucial to prevent this secondary damage and minimize further brain injury.

The other statements don’t fit because the damage occurring at the moment of impact is the primary injury, not secondary. Edema develops as part of the secondary process and contributes to worsening injury, rather than being a primary event. And secondary injury can arise from systemic factors affecting the brain, not solely from direct brain trauma.