Brain swelling, also known as cerebral edema, is a potentially life threatening condition. The brain is tightly encased within the skull. The close fit prevents the brain from jostling about during everyday activities. However, if brain swelling occurs, pressure quickly builds within the skull because there is little room to accommodate the swelling. Increased pressure due to brain swelling endangers its blood supply and may cause a bulging of the brain tissue, called herniation, through the bony opening where the spinal cord connects with the brain stem. Infections, injuries, tumors and strokes are common reasons for brain swelling.
Infection
An infection of the brain may trigger swelling. Think about when you get a small cut. The area around the cut typically turns red and swells as the immune system responds to clear the local infection. A similar response occurs with a brain infection; the entire surface of the brain is typically involved. Encephalitis is an infection of the brain tissue itself. An infection of the spinal fluid and protective tissues around the brain is termed meningitis. The National Institute of Neurological Disorders and Stroke reports that the classic symptoms of meningitis include high fever, severe headache, stiff neck and dulled consciousness. Encephalitis often presents more gradually with headache, confusion, memory loss, muscle weakness, hearing problems, speech difficulties, and personality changes. Both types of brain infections can lead to seizures and comas, and may be fatal.
Brain Trauma
Just as your knee or wrist swells if you injure it, your brain swells if it sustains an injury. The Centers for Disease Control and Prevention notes that 275,000 Americans are hospitalized annually with traumatic brain injuries. Severe concussions, brain contusions, penetrating brain injuries and bleeding in and around the brain can cause marked swelling. Brain swelling after injury often requires surgical intervention to relieve the increased intracranial pressure.
Brain Tumor
Brain tumors can cause brain swelling due to surrounding tissue inflammation. The Central Brain Tumor Registry of the United States estimates the diagnosis of 62,930 new cases of brain tumor in 2010. Noncancerous and cancerous tumors can arise in the brain; all age groups are affected. According to the American Brain Tumor Association, common symptoms of a brain tumor include persistent and progressive headaches, memory problems, difficulties with concentration, personality changes, visual or speech problems, isolated muscle weakness or paralysis, nausea and vomiting, and new onset seizures.
Stroke
Stroke occurs when an area of the brain loses its blood supply. Lack of oxygen and nutrients leads to a localized area of brain cell death and associated brain swelling. Strokes that occur due to a blood clot are called ischemic strokes. Those that occur due to rupture of a blood vessel are called hemorrhagic strokes. The American Heart Association reports that approximately 795,000 Americans suffered a stroke in 2006; more than 137,000 stroke-related deaths occurred that same year.
References
- National Institute of Neurological Disorders and Stroke: Meningitis and Encephalitis Fact Sheet
- Centers for Disease Control and Prevention: Meningitis Questions and Answers
- University of Maryland Medical Center: Viral Encephalitis Symptoms
- Centers for Disease Control and Prevention: Traumatic Brain Injury, Clinical Diagnosis and Management
- National Institute of Neurological Disorders and Stroke: Traumatic Brain Injury
