Pneumocystis Carinii Pneumonia

Pneumocystis carinii pneumonia (PCP) is caused by the fungal organism Pneumocystis carinii (recently renamed Pneumocystis jirovecii). This organism is widespread in the environment and is present in or breathed into the lungs of most people on a regular basis. It does not cause disease in healthy people.

PCP happens in people with weakened immune systems due to:

  • Certain cancers or cancer treatment.


  • Solid organ and/or bone marrow transplantation.

  • Corticosteroids or other medications that cause immune suppression.

Prior to AIDS becoming a common disease, this pneumonia was very uncommon.


The most common symptoms of infection are:

  • Fever.

  • Cough.

  • Shortness of breath especially with any exertion.

Symptoms in people with PCP and AIDS may develop slowly over several weeks. Other people with weakened immune systems and PCP usually get symptoms more suddenly.


The specific diagnosis of PCP requires seeing the organism by examining lung secretions under a microscope, The secretions are typically obtained by a procedure called bronchoscopy. On occasion, the organism can be identified in coughed up sputum. Because this infection is very serious, the patient's healthcare provider may suspect this disease and begin treatment without proof that this infection is present.


Treatment with antibiotics and sometimes steroid medicines is usually successful. Persons with weakened immune systems described above may also receive preventive antibiotic therapy when thought to be at high risk for this infection.


  • Take all medicines as prescribed. This infection must be treated for many weeks for a cure to be achieved.

  • Your caregiver will commonly provide preventive antibiotic therapy as well if your immune system remains suppressed. This treatment prevents both relapses and new episodes of this infection.

  • Smoking is a common cause of bronchitis and can contribute to pneumonia. Stopping this habit is important.

  • Make arrangements for a follow-up visit.


  • You develop a new fever, worsening shortness of breath or a possible reaction to your prescribed medicine. Common side effects of antibiotics used to treat PCP are nausea, vomiting, diarrhea or a skin rash.

  • If any of the symptoms which brought you initially into the emergency room are getting worse rather than better.

  • You develop an oral temperature above 102° F (38.9° C) after not having a temperature for one or more days.