Medicine
Traumatic Brain Injury (TBI)
Quick fact
TBI is a leading cause of disability and death worldwide, with over 50 million cases occurring each year.
Why this is interesting
A sudden blow to the head can instantly change a person's life—but what exactly happens inside the brain during a traumatic brain injury?
Read the full explanation
Understanding Traumatic Brain Injury (TBI)
When the head receives a forceful impact, the brain—a soft, jelly-like organ—can collide with the hard skull, causing bruising, tearing of nerve fibers, and bleeding. This initial damage is the primary injury. However, the brain's response to the trauma—swelling, reduced blood flow, and chemical changes—can cause additional harm called secondary injury, which evolves over hours to days. This is why immediate medical attention is critical.
A deeper explanation
The mechanisms of TBI involve both direct mechanical damage and a cascade of biological processes. The primary injury results from shearing forces that stretch and tear axons (diffuse axonal injury), contusions, and hemorrhages. Secondary injury includes excitotoxicity from excess glutamate, oxidative stress, inflammation, and raised intracranial pressure, which compresses brain tissue and compromises blood supply. These processes determine severity and prognosis. Understanding these mechanisms has led to treatments that focus on minimizing secondary injury, such as controlling intracranial pressure and avoiding hypoxia.