infections
Infections in People With Impaired Defenses
Introduction
Many disorders, drugs, and other treatments can cause a breakdown in the body’s Defenses Against Infection . Such a breakdown can lead to infections, which can even be caused by microorganisms that normally live harmlessly on or in the body ( Extensive burns:Risk of infection is increased because damaged skin cannot prevent invasion by harmful microorganisms. Medical procedures:During a procedure, foreign material may be introduced into the body, increasing the risk of infection. Such material includes catheters inserted into the urinary tract or a blood vessel, tubes inserted into the windpipe, and sutures placed under the skin. Drugs that suppress the immune system:These drugs include cancer chemotherapy drugs, drugs used to prevent rejection after an organ transplant (such asazathioprine,methotrexate, andcyclosporine), corticosteroids (such asprednisone), and biologic agents (such asadalimumaband others used for diseases such as ulcerative colitis, Crohn disease, rheumatoid arthritis, and other autoimmune diseases). Radiation treatments:Such treatments may suppress the immune system, particularly when bone marrow is exposed to radiation. Human Immunodeficiency Virus (HIV) Infection : (See also Overview of Infectious Disease .) Infections are more likely and usually more severe in older people than in younger people for several reasons: Aging reduces the immune system’s effectiveness ( see Effects of Aging on the Immune System ). Many long-term (chronic) disorders that are common among older people—such as Chronic Obstructive Pulmonary Disease (COPD) , Older people are more likely to be in a hospital or a nursing home, where the risk of acquiring a serious infection is greater. In hospitals, the widespread use of antibiotics allows antibiotic-resistant microorganisms to thrive, and infections with these microorganisms are often more difficult to treat than infections acquired at home or in the community ( see Hospital-Acquired Infections ). 