Edema is an abnormal accumulation of fluid in the interstitium, located beneath the skin and in the cavities of the body which cause severe pain. Clinically, edema manifests as swelling; the amount of interstitial fluid is determined by the balance of fluid homeostasis, and the increased secretion of fluid into the interstitium, or the impaired removal of the fluid can cause edema. Peripheral edema is edema (accumulation of fluid causing swelling) in tissues perfused by the peripheral vascular system, usually in the lower limbs. In the most dependent parts of the body (those hanging distally), it may be called dependent edema.
The condition is commonly associated with aging, but can be caused by many other conditions, including congestive heart failure, trauma, alcoholism, altitude sickness, pregnancy, hypertension, sickle cell anemia, or merely long periods of time sitting or standing without moving. Some medicines (e.g. amlodipine, pregabalin) may also cause or worsen the condition. Cerebral edema or cerebral oedema is excess accumulation of fluid in the intracellular or extracellular spaces of the brain. Certain changes in morphology are associated with cerebral edema: the brain becomes soft and smooth and overfills the cranial vault, gyri (ridges) become flattened, sulci (grooves) become narrowed, and ventricular cavities become compressed. Symptoms include nausea, vomiting, blurred vision, faintness, and in severe cases, seizures and coma. If brain herniation occurs, respiratory symptoms or respiratory arrest can also occur due to compression of the respiratory centers in the pons and medulla oblongata.
Treatment approaches can include osmotherapy using mannitol, diuretics to decrease fluid volume, corticosteroids to suppress the immune system, and surgical decompression to allow the brain tissue room to swell without compressive injury.