Edema/Inflammation: Mechanisms for Injury

The enlarged cranium of this baby is due to the excessive pressure caused from the build-up of fluid in the brain (hydrocephalus, unknown reason). The skull was able to expand because of the softness and separation of the plates. By the age of 2 (in a healthy child), the plates have typically grown together (along suture lines) and substantially hardened. For years (usually into adulthood), the skull plates and sutures continue to harden and fuse. Image by Syed Ikhwan, CC-BY-2.0.

The initial physical damage caused from a traumatic brain injury is not the only issue that can lead to harm and dysfunction. If the TBI rips open blood vessels or restricts the outflow of cerebrospinal fluid, the build-up of excess fluid (cerebral edema) may exert increased physical pressure that exceeds structural designs and cause additional injury. In response to the injury, there is also natural inflammation. As the body attempts to heal itself, various mechanisms are triggered and the wound site may fill with fluids meant for good. If the inflammation is long-term (from severity or repeated injuries), however, it may actually inhibit healing and create an environment that fosters neurodegenerative conditions and functional breakdown over time.