Mass effect is a phenomenon in which a focal lesion or contusion causes surrounding areas of brain tissue or brain structures to be compressed and injured due to the degree of space that leaking blood, cerebrospinal fluid, or edema takes up within the restricted skull space. The presence of mass effect following brain injury almost always indicates the presence of a more severe injury than a brain injury that occurs without resulting in mass effect. Mass effect can occur following traumatic brain injury, hemorrhagic cerebral stroke, subarachnoid cerebral aneurysm, non-traumatic cerebral aneurysm, and in the context of ruptured arterio–venous malformation.
In circumstances where a focal lesion or contusion causes mass effect within the brain, it becomes imperative to determine if surgical procedures or medications can be administered to reduce the impact of the space occupied by the lesion. Without emergent management, mass effect can dangerously increase...