Etymology: L, dis + usus, to make use of; Gk, phainein, to show
the physical and psychological changes, usually degenerative, that result from the lack of use of a body part or system. Disuse phenomena are associated with confinement and immobility, especially in orthopedics. Individuals treated for fractures and other orthopedic disorders must often be immobilized in traction for long periods. They are often deprived of sufficient interaction with the world around them and lose motivation, expectation, and even acquired abilities because of lack of practice. This disorientation is compounded by pain and therapeutic narcotic drugs commonly associated with the treatment of many illnesses and abnormal conditions. The physical changes often induced by continued bed rest constitute problems that affect many key areas and systems of the body, such as the skin, the musculoskeletal system, the GI tract, the cardiovascular system, and the respiratory system. Prolonged bed rest commonly subjects the patient's skin to abnormal pressure, moisture, and friction. Pressure exerted on the skin by the bed is slightly higher than capillary hydrostatic pressure and may cause collapse of the superficial capillaries and lead to ischemia and eventual tissue necrosis. A burning pain or absence of feeling may be the first sign of ischemia, followed by a rapid breakdown of the skin. Some indications of skin ischemia are redness, pain, edema, and skin breakdown. Unused muscles lose size and strength, often wasting until they are unable to perform their functions of support and contraction. Contractures are usually caused by flexion, because patients flex knees and hips whenever possible to relax muscles, especially when cold or in pain. The immobilized patient may experience bone demineralization caused by a restricted diet and decreased motility. Calcium and phosphorus are dependent on vitamin D for absorption from the gut and movement into the bones, and some nutrition experts describe calcium loss as a natural disuse phenomenon of bed rest. Muscle action is required to maintain blood flow to the bones, and the immobilized patient may not be capable of sufficient muscular activity to assure such blood flow, with its attendant delivery of critical nutrients and oxygen. The pooling of respiratory secretions is another disuse phenomenon caused by immobility and the horizontal position of the bed-rest patient. Some common therapeutic measures to deal with disuse phenomena are improvement of diet and nutrition, proper positioning and regular movement of the patient, meticulous hygiene, scrupulous skin care, and positive social interaction with the patient. Special alternating pressurized beds and range of motion machines for extremities may be used to improve circulation and muscle strength. See also hypostatic pneumonia.