American Medical Association Family Medical Guide - American Medical Association [410]
The first stage of TB may last several months. A person’s immune system will often stop the infection from spreading at this point by killing the bacteria or enclosing the bacteria in a small fibrous capsule, leaving scar tissue in about one third of cases. The infection may never develop beyond this phase. Sometimes the primary infection is not stopped and it spreads beyond the lymph nodes, which can carry it to other parts of the body. In secondary TB, the bacteria can lie dormant for years and be reactivated if a person’s immune system becomes impaired by another disease or by malnutrition. However, in many cases, no triggering factor can be identified.
Symptoms
Usually, TB does not cause symptoms. You may not know you have been exposed to the TB bacterium until you have a chest X-ray for other reasons or a tuberculin skin test (see below). If a person becomes infected, the symptoms may include slight fever, muscle aches, night sweats, weight loss, fatigue, shortness of breath, chest pain, and a cough that produces blood-stained phlegm.
Tuberculin Skin Test
A tuberculin skin test is used to determine if you have ever been exposed to the TB bacterium. After cleaning a small area of skin with an alcohol-soaked pad, a health care worker injects a small dose of tuberculin (a purified protein extract of TB bacteria) into the skin of your forearm. If you don’t have a skin reaction at the site of the injection in 2 days, it indicates that you have never been exposed to the bacterium and you have no immunity against it. If a small area of the skin around the site becomes red, hard, and slightly swollen, it indicates that you have been infected with TB, either through exposure to the bacterium or from a previous immunization.
Diagnosis
If you have any symptoms of TB or if you have been exposed to someone who has it, your doctor will examine you, take chest X-rays, and perform a tuberculin skin test. If the X-ray shows signs of infection, he or she will take samples of phlegm to test for the presence of the TB bacterium. If you have ever had TB, the chest X-ray may show shadows that indicate scarred, healed areas of TB.
Treatment
If you have TB, your doctor will prescribe both antibacterial and antibiotic medications, sometimes as many as three or four different drugs, which must be taken exactly as prescribed to be effective. The treatment is prolonged, lasting 6 to 9 months, but it can cure the disease. Try to eat a well-balanced diet and get as much rest as possible during treatment.
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Disorders of the Brain and Nervous System
The nervous system is made up of two parts—the central nervous system and the peripheral nervous system. The brain and spinal cord comprise the central nervous system, which coordinates all the body’s interactions with the environment. The human brain is a highly complex organ that regulates most of the body’s functions and changes in response to stimulation from the environment. The brain uses the outside world to build itself after birth and goes through critical periods in childhood during which brain cells need to have specific kinds of stimulation to develop such powers as language, smell, vision, muscle control, and reasoning. Not only does the brain have the ability to change in response to stimulation, such as learning new information, it also continues to make new brain cells throughout life.
The peripheral nervous system is a vast network of nerves that runs from the spinal cord to the rest of the body. The peripheral nerves connect at different levels with the spinal cord, through which information flows back