Brain swelling, also called cerebral edema, can affect the brain's ability to function. Injuries, infections, toxin exposures and brain tumors can cause brain swelling. The University of Connecticut Health Center notes that two types of brain swelling can occur: vasogenic edema and cytotoxic edema. Vasogenic edema occurs when the blood--brain barrier, the protective layer around the brain, becomes damaged. Cytotoxic edema results from a dysfunction of both sodium--potassium pumps and calcium transports, mechanisms for moving molecules in and out of brain tissue. If untreated, brain swelling can result in permanent brain damage.
Increased Intracranial Pressure
Swelling in the brain presses against surrounding brain tissue, causing increased intracranial pressure, or pressure inside the skull. Symptoms of increased intracranial pressure include vomiting, worsening headaches, impaired thinking and changes in consciousness. The Merck Manual Home Edition notes that when the amount of pressure increases in the brain, these symptoms worsen, and new symptoms can appear. For example, as the pressure in the brain increases, patients become unresponsive. A physical change from increased intracranial pressure includes widening of the pupil. The University of Connecticut Health Center adds that patients with increased intracranial pressure may have third nerve palsy, which causes weakness on one side of the body.
Herniation
The Merck Manual Home Edition explains that the increased intracranial pressure from brain swelling results in a herniation, in which the pressure pushes the brain tissue to another area in the skull. Herniation also affects the blood vessels and the cerebrospinal fluid, the fluid that protects and surrounds the brain. This condition can result in a coma. If the pressure affects the brain stem, it can in turn affect a patient's heart and breathing. Too much pressure on the brain stem can result in death.
Permanent Brain Damage
Kids Health notes that brain swelling can result in permanent brain damage, affecting normal function. For example, memory loss can occur, impairing patients' abilities to retrieve memories or create new ones. If a patient cannot form new memories, she will have difficulty learning. If the brain swelling affects the motor regions of the brain, patients may lose control of their muscles. This lack of muscle control can cause problems with movement and coordination. Speech problems can also occur. For example, if the brain swelling affects the frontal lobe, the part of the brain by the forehead, patients can have problems forming words when speaking.
