Pneumocystis carinii pneumonia

Causes and Risks:
Pneumocystis carinii is found in the lungs of humans and wild and domesticated animals. Typically, P. carinii is not a pathogen (disease-causing organism) in healthy humans. In people with weak immune systems, however, it can cause Pneumocystis carinii pneumonia (PCP). Therefore, the disease is rare in the general population, although asymptomatic infections occur in many people early in life.

PCP primarily affects hospitalized premature infants, cancer patients, patients being treated with immunosuppressive medications for the management of organ transplantation or cancer, and AIDS patients. Before the AIDS epidemic, PCP was seldom seen. It is now recognized with increased frequency in non-AIDS immunocompromised patients. PCP occurs in approximately 80% of AIDS patients and is the major cause of death in that group.

There are presently only a few effective chemotherapeutic agents available against this infection: pentamidine, trimethoprim-sulfamethoxazole, and dapsone. Research on the effectiveness of other drugs is presently in progress.

In the older child and adult pneumocystis pneumonia may begin suddenly with fever , rapid breathing ( tachypnea ) and a feeling of being short of breath. As the illness progresses cough , retraction, nasal flaring and cyanosis develop. Oxygen is required because the infection interferes with the exchange of gasses across the lung membranes.

Prevention:
Prophylaxis (preventive) therapy is recommended for AIDS patients and some other high-risk persons. Several treatment options are available, although only one is fairly universally recognized. Aerosolized pentamidine administered monthly has been shown to prevent or delay the development of Pneumocystis carinii pneumonia.

Symptoms:



Signs and Tests:



Treatment:
Oral, intravenous , and inhaled medications are used in the treatment of PCP. Pentamidine, dapsone, and trimethoprim-sulfamethoxazole are the most available and most commonly used agents. Pentamidine may be given in aerosolized form both as treatment and to prevent reinfection. For preventive measures, nebulized pentamidine is given once a month.

Because PCP causes problems with gas exchange within the lung, oxygen is often required to maintain normal oxygen levels.

Prognosis:
Pneumocystis carinii pneumonia can be life threatening and death may occur due to respiratory failure. Early treatment reduces the death rate. People with AIDS may have repeated infections. For these people pneumocystis pneumonia may be a terminal event.

Complications:



Call Your Healthcare Provider:
Call for an appointment with your health care provider if you belong to a high-risk group and have developed a fever , cough , or any type of breathing difficulty .


This is an illustration of the major features of the lungs and bronchial tree. The inset is of the alveoli. They are the microscopic blood vessel-lined sacks in which oxygen and carbon dioxide gas are exchanged.