Frozen shoulder, also know as adhesive capsulitis, can occur spontaneously. Some individuals have a higher chance of incurring it. It is most common in middle-aged women. The reasons why it occurs are poorly understood. Associations with several diseases have been noted.
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The shoulder joint is composed of the scapula and the humerus, arm bone. The scapula has a shallow concave surface, the glenoid. The rounded end of the humerus sits on the glenoid. To allow for the wide range of motion that a normal shoulder has, there normally is thin loose joint capsule connecting the humerus and glenoid.
Frozen shoulder begins with inflammation of the shoulder. The inflammatory process can be very painful. There is excess growth of the capsule lining, or synovium. The inflammatory process can produce excess fluid or scar tissue. In patients with a frozen shoulder, the capsule becomes contracted and thickened as more collagen is formed. As the capsule thickens and shortens, the shoulder motion is dramatically limited.
There are two ways a frozen shoulder can occur after another injury. The most common way is for the shoulder to be injured. An inflammation process starts in the shoulder. The second reason a shoulder can be affected is when a nearby joint such as the elbow or wrist is injured. If the shoulder is kept in a relatively fixed position by using a sling, it can become stiff. An inflammation process begins in the shoulder.
Patients presenting with adhesive capsulitis should be screened for symptoms of diabetes. Increased thirst, increased urination, unexplained weight loss, and fatigue are are signs of diabetes. Frozen shoulder occurs in 10 percent to 20 percent of diabetics, according to the American Academy of Orthopaedic Surgeons. It is not understood why frozen shoulder occurs in diabetics.
Thyroid disease resulting in either low levels or high levels of thyroid hormone has been associated with adhesive capsulitis. Hashimotos disease and Graves disease are thyroid diseases that can cause adhesive capsulitis in younger patients. Unexplained weight gain or loss is characteristic of thyroid disease, according to the website of the Endocrine Society. In autoimmune diseases, the body produces antibodies that attack the body's own organs. Examples of autoimmune disease are are juvenile diabetes, Graves disease, and Hashimotos disease. Frozen shoulder is associated with these and other autoimmune diseases. Parkinsons disease has been associated with adhesive capsulitis.
Heart and Lung
Frozen shoulder can occur after either lung or heart disease. It has been seen after heart surgery as well as after heart attacks. Patients who have had a stroke are at risk for adhesive capsulitis from the heart association as well as from loss of motion. Patients with tuberculosis have an increased chance of developing a frozen shoulder.