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