SYSTEMIC
DISEASES Many nonrespiratory diseases can have major or minor effects on the respiratory system. For example,
sarcoidosis, a disease characterized by collections of inflammatory cells in multiple organs in the body, can involve the lungs. Blood clots originating in the veins of the legs or heart can break loose and travel to the lungs, creating a blockage in the blood vessels of the lung, called a pulmonary embolism. Heart
failure may cause fluid to collect in the lungs, leading to shortness of breath on exertion and attacks of breathlessness at night. Kidney failure may also be associated with collection of fluid and with other changes in the lung. Autoimmune disorders that cause the individual's immune system to attack their own body can also affect the lung. Examples of these
diseases are lupus erythematosus, polyarteritis, scleroderma (see collagen disease), and rheumatoid arthritis.