American Medical Association Family Medical Guide - American Medical Association [381]
Alternatively, your doctor may recommend a stem cell transplant (see page 624) from a sibling if you are otherwise healthy and have a sibling with matching tissue type. The stem cells are injected into one of your veins and make their way to the bone marrow, where they take over the production of blood cells. You may be given granulocyte-stimulating factors after the transplant to enhance the functioning of the donor stem cells within your bone marrow.
Neutropenia and Agranulocytosis
Neutrophils and granulocytes are white blood cells that are the body’s first defense against infections. Normally, neutrophils and granulocytes are produced in the bone marrow and released into the bloodstream. In neutropenia, neutrophils are not being produced properly. In agranulocytosis, granulocytes are not being produced at all. The resulting severe reduction in either type of white blood cell significantly decreases the body’s ability to fight infections.
Neutropenia is usually a complication of chemotherapy (see page 23). Occasionally, neutropenia results from a medication taken for another disorder. Agranulocytosis can result from a viral infection or from an errant immune response that mistakenly attacks a person’s own white blood cells. Neutropenia or agranulocytosis can be the first sign of leukemia (see page 621) or aplastic anemia (see previous page).
Symptoms
The main symptom of both neutropenia and agranulocytosis is susceptibility to infections, especially in the mouth and throat. In some cases of agranulocytosis, infections such as pneumonia progress unusually rapidly and can be extremely severe or fatal. If you have frequent infections, see your doctor, especially if you are taking any prescription or over-the-counter drugs or supplements, because some medications can damage the bone marrow.
Diagnosis
Make sure your doctor knows about all medications you are taking. He or she will probably want you to have a blood test. If the results of the test show that you may have neutropenia or agranulocytosis, your doctor will confirm the diagnosis by performing a bone marrow aspiration and biopsy, in which a small amount of your bone marrow is removed through a needle and syringe and examined under a microscope.
Treatment
The treatment for neutropenia and agranulocytosis involves waiting for the levels of neutrophils and granulocytes to return to normal while dealing with any complications that may occur, including bleeding (which is treated with infusions of red blood cells and platelets) and infections (which are treated with antibiotics). In some cases, drugs called hematopoietic growth factors may be used to stimulate the production of white blood cells. If the cause is a medication you have been taking for another condition, your doctor will ask you to stop taking that drug and will prescribe a substitute.
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Disorders of the Respiratory System
Respiration is the process by which oxygen reaches the body’s cells and is used by them to produce energy. Internal respiration is the exchange of gases between the blood and body tissues. External respiration, which we call breathing, is the exchange of gases between the lungs and the blood.
During breathing, your lungs take in oxygen from the air when you inhale and release carbon dioxide from your blood when you exhale. The channel that carries the air in and out of your lungs is called the respiratory tract and includes the sinuses, nasal cavity, pharynx (throat), larynx (voice box), trachea (windpipe), lungs, and a system of arteries, veins, and smaller vessels that carry blood to and from the lungs.
The respiratory system
The respiratory system is divided into the