Pneumocystis pneumonia (PCP) is a serious infection that causes inflammation and fluid buildup in the lungs. It is caused by a fungus called Pneumocystis jiroveci. Likely spread through the air, this fungus is very common. Most people are exposed to it by age 3 or 4. A healthy immune system can easily control it. But it causes a type of pneumonia in people with weakened immune systems, such as those with HIV (human immunodeficiency virus). This is why it's called an opportunistic infection. Rarely, PCP can affect other parts of the body including the lymph nodes, liver, and bone marrow.
Before HIV medication was available, PCP occurred in 70% to 80% of HIV-positive people. The number of cases has decreased a great deal. This is due to highly active antiretroviral therapy (HAART) and PCP-preventive drugs.
Here are other things you should know:
PCP is still the most common opportunistic infection in HIV-positive people. Those with a CD4 cell count less than 200 are at highest risk. (CD4 cells are a type of immune system cell. HIV attacks these cells.)
30% to 40% of HIV-positive people develop PCP if they wait until their CD4 cell count drops to around 50 to receive treatment.
PCP is still a major cause of death in AIDS patients in the United States.
PCP is a very treatable and preventable infection.
Symptoms of Pneumocystis Pneumonia
At first, PCP may cause no symptoms. Call your doctor right away if you have any of these signs or symptoms of PCP. It can be fatal.
Mild and dry cough or wheezing
Shortness of breath, especially with activity
Major weight loss
Chest pain when you breathe
Diagnosing Pneumocystis Pneumonia
PCP can be diagnosed with the help of medical tests. These may include:
Special lab tests examining discharge from the lungs and airways (called sputum induction)
Blood tests including evaluation for decreased oxygen levels
If sputum induction is unsuccessful, then a fluid sample taken from the lungs (during a procedure called a bronchoscopy) may be necessary
Sometimes a biopsy will be needed to confirm the diagnosis.