Question:medium
In a patient with head injury, damage in the brain is aggravated by:
In a patient with head injury, damage in the brain is aggravated by:
Show Hint
High glucose feeds anaerobic acidosis in injured brain.
Updated On: Jun 24, 2026
- Hyperglycemia
- Hypothermia
- Hypocapnia
- Raised serum osmolality
Show Solution
The Correct Option is A
Solution and Explanation
The theme here is secondary brain injury, the wave of damage that follows the initial trauma and that we try hard to limit. The right choice is the one that makes that secondary injury worse.
Glucose is the trap. In healthy brain, glucose is just fuel, but in injured or under perfused tissue the cells switch to anaerobic metabolism. Excess glucose then drives extra lactate and intracellular $acidosis$, and the more acidic, ischemic environment kills more neurons. High glucose levels after trauma consistently track with worse outcomes, so hyperglycemia aggravates the damage.
Walk through the rest. Cooling the brain lowers its metabolic demand, so hypothermia is broadly neuroprotective, not harmful. Low carbon dioxide constricts cerebral vessels; a short burst of controlled hyperventilation can buy time against a spiking intracranial pressure, but it is a double edged tool, so hypocapnia is only conditionally damaging. That nuance is why the recalled key ranked hyperglycemia above hypocapnia.
Finally, deliberately raising serum osmolality with mannitol or hypertonic saline pulls water out of swollen brain and is a treatment for raised pressure, so it cannot be the aggravating factor.
\[\boxed{\text{Hyperglycemia}}\]
Glucose is the trap. In healthy brain, glucose is just fuel, but in injured or under perfused tissue the cells switch to anaerobic metabolism. Excess glucose then drives extra lactate and intracellular $acidosis$, and the more acidic, ischemic environment kills more neurons. High glucose levels after trauma consistently track with worse outcomes, so hyperglycemia aggravates the damage.
Walk through the rest. Cooling the brain lowers its metabolic demand, so hypothermia is broadly neuroprotective, not harmful. Low carbon dioxide constricts cerebral vessels; a short burst of controlled hyperventilation can buy time against a spiking intracranial pressure, but it is a double edged tool, so hypocapnia is only conditionally damaging. That nuance is why the recalled key ranked hyperglycemia above hypocapnia.
Finally, deliberately raising serum osmolality with mannitol or hypertonic saline pulls water out of swollen brain and is a treatment for raised pressure, so it cannot be the aggravating factor.
\[\boxed{\text{Hyperglycemia}}\]
Was this answer helpful?
0
