Causes of Immunodeficiency and Opportunistic Infections:
An immunodeficiency disorder may be present at birth or may develop later in life, often as a result of another disorder. Congenital immunodeficiency disorders are usually hereditary. Becoming evident during infancy or childhood. There are more than 70 congenital immunodeficiency disorders; all are relatively rare. Acquired immunodeficiency disorders are much more common. Some immunodeficiency disorders shorten lifespan, others persist throughout life but do not affect lifespan, and a few resolve with or without treatment.
Immunodeficiency disorders are grouped by which part of the immune system is affected. They may involve problems with antibodies (due to abnormalities in white blood cells) or complement proteins. The affected component of the immune system may be missing, reduced in number, or abnormal and malfunctioning
Aquired immunodeficiency disorders may result from almost any prolonged serious disorder. Examples are cancer, blood disorders (such as aplastic anemia, leukemia, and myelofibrosis), kidney failure, diabetes, liver disorders, and spleen disorders. Diabetes can result in an immunodeficiency disorder because white blood cells do not function well when the blood sugar level is high. Infections can also cause immunodeficiency disorders. Human immunodeficiency virus (HIV) infection results in acquired immunodeficiency syndrome (AIDS), the most common severe acquired immunodeficiency disorder.
Undernutrition-whether of all nutrients or only one-can impair the immune system. When undernutrition causes weight to decrease to less than 80% of recommended weight, the immune system is usually impaired. A decrease to less than 70% usually results in severe impairment.
Use of certain drugs called immunosuppressants may result in an acquired immunodeficiency disorder. These drugs are intentionally used to suppress the immune system. For example, immunosuppressants are used to prevent rejection of a transplanted organ or tissue; and corticosteroids, a type of immunosuppressant, are used to suppress inflammation due to various disorders. However, immunosuppressants also suppress the body's ability to fight infections and perhaps to destroy cancer cells. Chemotherapy and radiation therapy can also result in immunodeficiency disorders.
Symptoms of Immunodeficiency and Opportunistic Infections:
People with an immunodeficiency disorder tend to have one infection after another. Usually, respiratory infections develop first and recur often. Most people eventually develop severe bacterial infections that persist, recur, or lead to complications. For example, sore throats and head colds may progress to pneumonia. However, having many colds does not suggest an immunodeficiency disorder.
Infections of the skin and the membranes lining the mouth, eyes, and digestive tract are common. Thrush (Candidiasis), a fungal infection of the mouth, may be an early sign of an immunodeficiency disorder. Skin infections by bacteria or viruses are also common. Bacterial infections (with staphylococci, for example) may cause pyoderma, in which the skin is covered with pus-filled sores. Warts (caused by viruses) may also occur.
Many people lose weight. Children tend to develop slowly. Other symptoms vary depending on the severity and duration of the infections
