Weakness
(See Loss of Energy)
Progressive weakness may occur in old age, particularly when the elderly person has some chronic illness. It occurs in patients of any age who have been long confined to bed. Even after recovery from an illness the patient will need to "get his strength back," increasing his activities gradually.
General weakness occurs in illnesses with fever, and in systemic diseases such as tuberculosis, brucellosis, and malaria.
Weakness is a usual symptom in conditions in which there is an insufficient amount of oxygen available to the tissues, as in anemia and certain forms of heart disease. It occurs in persons who follow fads in diet, particularly when the diet does not contain enough protein. In anorexia nervosa, a disease in which the patient has a very poor appetite, there is weakness from inadequate food intake.
Weakness accompanies such disorders of the endocrine organs as Addison's disease, pituitary insufficiency, thyroid disease in which there is either hypo- or hyper-function of the thyroid gland, diabetes mellitus, and hyperparathyroidism.
Weakness is common in viral hepatitis and in some other liver disorders. It occurs in those kidney diseases in which the kidneys become unable to eliminate the necessary amounts of the products resulting from the metabolism of proteins.
Some diseases of the nervous system destroy the nerve centers controlling the actions of the muscles or of the nerve fibers which lead to these muscles, and weakness results. Such conditions as "stroke," tumors of the brain or other nervous tissues, and poliomyelitis cause weakness of the muscles which would normally be controlled by the affected nerve structures. Weakness occurs in such muscular disorders as myasthenia gravis, myotonia dystrophica, and progressive muscular dystrophy. Weakness occurs in cases of chronic alcoholism or in persons who have used certain drugs for long periods of time (particularly bromides, barbiturates, cocaine, or morphine and its derivatives).
