Pneumocystis pneumonia (PCP) is an infection caused by Pneumocystis jiroveci, a microscopic fungus that lives in the lungs of many people. PCP is a rare disease in healthy people. However, it can cause a serious pneumonia in infants who have AIDS, cancer, or other conditions that weaken the immune system.

PCP is the most common pediatric illness associated with AIDS, especially in babies younger than 6 months old, and its prevention is very important in AIDS care since it is an important cause of mortality in people with AIDS.

In kids who are already seriously ill, symptoms of this form of PCP begin suddenly with a fever, a cough, and difficulty breathing. A child may not cough up any mucus because it is usually too thick to come up with the cough. Other symptoms can include weight loss and night sweats.

Infants who are weak or sick also can develop PCP. Usually the infant is 3 to 6 months old and has no fever, but gradually begins to breathe faster than normal. As the lung infection gets worse, breathing becomes more difficult, and the baby's chest muscles may begin to retract (pull in abnormally) with each breath. The child's lips, fingernails, and skin also may turn blue or gray.

Diagnosing PCP

A doctor can sometimes diagnose pneumocystis pneumonia by a characteristic X-ray pattern or if suspected in individuals with fever, cough, difficulty breathing who also have very low oxygen levels in their bloodstream. It is confirmed by finding the organism in lung fluids that have been examined in the laboratory. The doctor may need to use a bronchoscope to take a tissue sample from inside the lungs. This sample will be sent to a laboratory where special chemical stains can identify the pneumocystis organism.

Even if your child has no other medical problems, call your doctor immediately if your child has unusually rapid breathing or difficulty breathing, is coughing, or has a blue or gray color to the nails, lips, or skin.

Treating PCP

Early treatment is key because PCP is a potentially life-threatening infection. Antibiotics, either alone or in special combinations, are usually used to treat pneumocystis pneumonia. They may be given by mouth or intravenously (into the veins) for at least 2 weeks. If the child has AIDS, antibiotic treatment will probably last about 3 weeks. Depending on the severity of the PCP infection, the doctor may add a steroid medication.

If your child has any condition that severely weakens the immune system, check with your doctor about giving your child antibiotics to prevent pneumocystis infection.

All infants born to HIV-infected mothers should begin treatment to prevent PCP at 1 month of age until it's known for sure whether they have the HIV infection.

Transmission of PCP

Research is ongoing about how pneumocystis is spread. Scientists believe that it's transmitted through the air, but cannot yet point to sources in the environment. Human-to-human spread may be possible, since there have been hospital outbreaks among sick infants and children with weakened immune systems.

Because of the seriousness of this infection, most kids who have symptoms of pneumocystis infection are treated in the hospital. Some of the different antibiotics that may be used to treat pneumocystis can have side effects, which are easier to monitor in a hospital.

Reviewed by: Yamini Durani, MD
Date reviewed: June 2011