Why Do Injured Joints Swell Up?
The swelling of an injured joint, like a knee or an ankle, is caused by the multiplication of normal cells to cushion the affected part. This sudden increase is called hyperplasia. There is also a certain amount of internal bleeding as a result of injury. Swellings are divided into two main groups, false tumors and true tumors.
The inflammatory swellings that appear after joint injuries belong to the first group, which includes bruises, black eyes, sprains, fractures and infectious swellings such as boils and abscesses. Swollen joints can be eased by the application of cold compresses, or pads, and ice packs. Firm bandages are used to give support.
True tumors or swellings are composed of masses of tissue developed from body cells which already exist. They have a tendency to keep growing. Some of these tumors have normal cells and are said to be benign or harmless, in others the cells are slightly different from their parents and the tumors are generally malignant.
Joint swelling may be accompanied by other symptoms, including stiffness, pain, redness, warmth, and apparent loss of range of motion of the joint. Depending upon the exact cause, swollen joints may occur singly, or multiple joints in the body may be involved at one time. The many arthritis conditions are a common cause of swollen joints.
Swollen joints happen when there’s an increase of fluid in the tissues that surround the joints. Joint swelling is common with different types of arthritis, infections, and injuries. A swollen joint is a symptom of the following health conditions:
Osteoarthritis (OA). OA is the “wear-and-tear” arthritis that usually happens with aging or after injury. With OA, there’s a wearing down of the cartilage that cushions the ends of the bones. OA may cause joint swelling in those joints that bear weight over a lifetime, such as knees, hips, feet, and spine. Except for the pain in the affected swollen joint, you usually do not feel sick or tired.
Rheumatoid arthritis (RA). RA is an inflammatory arthritis that can happen at any age — even in young children. RA causes painful, stiff, and swollen joints. Usually, RA affects hands, feet, and knees, but it can also affect most joints and other parts of the body. RA symptoms can interfere with daily activities.
Gout . Gouty arthritis usually strikes suddenly, with severe joint pain, swelling, warmth, and redness, often in the big toe (about 50% of cases). Gout causes a painful, swollen joint that’s so severe that the weight of bed sheets can cause distress. It usually involves one joint when it strikes, but occasionally gout can affect more than one joint.
With gout, uric acid — a normal chemical in the body — forms crystals that deposit in the joints, causing inflammation and pain. The crystals may also deposit in other areas to become nodules under the skin or stones in the kidney.