A severe wasting (atrophy) of the body produced as the consequence of disease. Wasting occurs, of course, in any person who is starved for any reason, but the term cachexia usually is reserved for those in whom an underlying illness exists and who usually require treatment in addition to a well-balanced diet in order to regain normal health.
Simple starvation plays some part in many cases of true cachexia. For example, a patient with cancer of the esophagus (“gullet”) or stomach may be quite unable, for purely mechanical reasons, to take in enough food to maintain health. In starvation, body fat is lost first; only when this has been consumed for energy production will essential tissue, such as muscles, be broken down. In some debilitating diseases, loss of body fat and muscle wasting often occur simultaneously as a relatively early sign of the disease and cannot always easily be explained by a loss of appetite or diminished food intake. This is particularly true of patients who have cancer (malignant cachexia).
In taking a patient’s medical history, a physician often will inquire about any recent loss of weight. If there has been considerable weight loss over the preceding weeks or months, the physician inquires further to find out if the weight loss is associated simply with a reduction in food intake as a result of anxiety or depression, or if there may be some underlying disease. Lastly, certain glandular disorders including overactivity of the thyroid gland (hyperthyroidism) and a rare disorder of the pituitary gland (known as pituitary cachexia or Simmonds’ disease) – may cause severe weight loss and wasting of the tissues, which can usually be corrected by appropriate treatment of the glandular disorder.