1. There’s little room to spare in the cranium.
Traumatic brain injuries (TBI) can cause inflammation and swelling or bleeding from damage to brain tissue and blood vessels. Bleeding may occur within the brain(an intracranial hemorrhage) or the protective layers that surround it, such as an epidural, subdural or subarachnoid hemorrhage.
The brain is tightly enclosed within the skull. Bleeding and inflammation cause a rise in intracranial pressure (ICP), which squeezes and damages brain structures, within that space. As ICP increases, sections of the brain may shift to different areas within the skull, or into the opening where the spinal cord enters the cranium, through a process known as herniation. The higher and longer ICP rises, the degree of permanent disability and likelihood of death increases.
Signs of increased ICP include altered mental status, unequal or nonreactive pupils, posturing, or seizures, as well as bradycardia and hypertension (Cushing’s Phenomenon).