Pneumocystis Pneumonia
Pneumocystis pneumonia (PCP) is a serious lung infection caused by the fungus Pneumocystis jiroveci, primarily affecting individuals with weakened immune systems, particularly those with acquired immunodeficiency syndrome (AIDS). The fungus can be airborne, and while it is often present in the lungs of healthy individuals without causing illness, it poses significant risks to those with compromised immunity, such as cancer patients or those with autoimmune diseases. Symptoms of PCP typically manifest over weeks or months and include shortness of breath, fever, dry cough, chest tightness, and overall weakness. Diagnosis involves examining sputum samples, often requiring procedures like bronchoscopy to obtain adequate specimens. Treatment varies based on infection severity, with options ranging from oral medications for mild cases to intravenous treatments in hospitals for severe cases. Preventive measures are crucial for high-risk individuals, particularly when certain health indicators, such as a low CD4 cell count in HIV patients, are observed. Despite treatment, PCP has a notable mortality rate, highlighting the importance of early detection and intervention. Preventive therapies can reduce the likelihood of recurrence, but individuals who have had PCP are at increased risk of subsequent infections.
Pneumocystis Pneumonia
- ANATOMY OR SYSTEM AFFECTED: Lungs, respiratory system
Definition
Pneumocystis pneumonia (PCP) is a lung infection caused by the fungus Pneumocystis jiroveci (formerly called P. carinii). This preventable infection affects people who have a weakened immune system, and it is the most common serious infection among people with acquired immunodeficiency syndrome (AIDS).
Causes
Most scientists believe that P. jiroveci is spread in the air. It is not clear if it lives in soil or elsewhere. In healthy people, the fungus can exist in the lungs without causing pneumonia. However, in people who have a weakened immune system, PCP may cause a lung infection.
Risk Factors
People who are at increased risk for PCP include those who have AIDS or cancer and those who are being treated for cancer. Individuals who suffer from autoimmune diseases are also at risk of contracting pneumocystis pneumonia, though cases in those individuals are rarer.
Symptoms
Symptoms of PCP usually develop over the course of a few weeks or months. The main symptoms are shortness of breath, fever, dry cough, tightness in the chest, and weakness. One should consult a doctor immediately if experiencing any of these symptoms.
Screening and Diagnosis
A sample of the patient’s sputum is examined under a microscope. Sputum is mucus from the lungs that is produced when one coughs. The doctor will collect samples by giving the patient a vapor treatment to induce coughing or through a bronchoscopy, an instrument that is inserted into the airway.
Treatment and Therapy
Treatment will depend on the seriousness of the infection. For mild cases, the patient will be given medication in pill form. For severe cases, the patient will probably be treated in a hospital and receive medication by IV (intravenously).
Several drugs are used to treat PCP, including trimethoprim-sulfamethoxazole (TMP-SMZ, Bactrim, Septra, Cotrim), which is available in pill and liquid forms; dapsone plus trimethoprim; primaquine plus clindamycin; atovaquone; pentamidine (given by IV); trimetrexate plus folinic acid; and corticosteroids, given in severe cases when blood oxygen pressure falls below a certain level. Most of these treatments have side effects. Even when treatment is given for PCP, the death rate is 15 to 20 percent.
Prevention and Outcomes
Persons who are at risk for PCP may be given medicine to prevent the disease. In general, for those with human immunodeficiency virus (HIV) infection, preventing PCP with medication is recommended if that person’s CD4 cell count falls below 200. Other conditions, such as having a temperature higher than 100° Fahrenheit that lasts for more than two weeks or getting a fungal infection in the mouth or throat, are reasons to start preventive therapy. Some of the same drugs used to treat an infection can be taken regularly to prevent the infection. These drugs include TMP-SMZ, dapsone, atovaquone, and pentamidine aerosol.
If a person gets PCP once, he or she is more likely to get it again. Each time one gets it, the PCP causes damage to the lungs. The body can suffer side effects from the drugs.
Pneumonia vaccine only protects against a different kind of pneumonia. It will not keep a person from getting PCP.
Bibliography
"AIDS InfoNet: Pneumocystis Pneumonia (PCP)." AIDS InfoNet, aidsinfonet.org. Accessed 31 Oct. 2024.
"Pneumocystis Pneumonia (PCP)." American Academy of Family Physicians, May 2023, familydoctor.org/pneumocystis-pneumonia-pcp-and-hiv/. Accessed 31 Oct. 2024.
Centers for Disease Control and Prevention. "You Can Prevent PCP: A Guide for People with HIV Infection." CDC, www.cdc.gov/hiv. Accessed 31 Oct. 2024.
Corrin, Bryan, and Andrew G. Nicholson. Pathology of the Lungs. 2nd ed., Churchill Livingstone, 2006.
Fan, Hung Y., et al. AIDS: Science and Society. 5th ed., Jones and Bartlett, 2007.
Hughes, Walter T. "Pneumocystis carinii" Pneumonitis. Rev. ed., CRC Press, 1987.
West, John B. Pulmonary Pathophysiology: The Essentials. 7th ed., Wolters Kluwer, 2008.