Pneumocystis Pneumonia
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Pneumocystis Pneumonia

(PCP; )

Pronounced: new-mo-SIS-tis new-MOAN-ya

En Español (Spanish Version)

Definition

Pneumocystis pneumonia (PCP) is a form of pneumonia that causes a lung infection. PCP is caused by a fungus called Pneumocystis jiroveci ( P. jiroveci ). This was previously called Pneumocystis carinii .

This infection affects people who have a weakened immune system. It is the most common serious infection among people with AIDS .

PCP can be prevented.

The Lungs (Cut-away View)

Nucleus factsheet image

© 2008 Nucleus Medical Art, Inc.

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

A risk factor is something that increases your chance of getting a disease or condition. People who are at increased risk for PCP include those who:

  • Have AIDS
  • Have cancer
  • Are getting treatment for cancer

Symptoms

Symptoms of PCP usually develop over the course of a few weeks or months. The main symptoms of PCP are:

  • Shortness of breath
  • Fever
  • Dry cough
  • Tightness in the chest
  • Weakness

See your doctor immediately if you experience these symptoms.

Diagnosis

To diagnose PCP, a sample of your sputum is examined under the microscope. Sputum is mucus material from your lungs that is produced when you cough. Your doctor will collect samples of your sputum by giving you either:

  • A vapor treatment to make you cough
  • A bronchoscopy , during which an instrument is inserted into your airway

Treatment

If you get PCP, your treatment will depend on how serious the infection is. If you have a mild case, you will be given medication in pill form. If you have a severe case, you will probably be treated in the hospital and receive medication intravenously.

There are several drugs used to treat PCP:

  • Trimethoprim-sulfamethoxazole (TMP-SMZ): this is a combination of two medicines and has several brand names, such as Bactrim, Septra, and Cotrim. It is available in pill and liquid forms
  • Dapsone plus trimethoprim
  • Primaquine plus clindamycin
  • Atovaquone
  • Pentamidine (given intravenously)
  • Trimetrexate plus folinic acid
  • Corticosteroids: given in severe cases when blood oxygen pressure falls below a certain level

Most of these treatments have side effects which you and your doctor should take into account when considering treatment options.

Even when treatment is given for PCP, the death rate is 15% to 20%. It’s best to avoid getting PCP in the first place.

Prevention

PCP can be prevented. If you are at risk for PCP because of a weakened immune system, your doctor may recommend that you take medicine to prevent getting it. In general, for those with HIV infection, preventing PCP with medication is recommended if your CD4 cell count falls below 200. Other conditions, like having a temperature above 100˚F that lasts for more than two weeks, or getting a fungal infection in your 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:

  • TMP-SMZ
  • Dapsone
  • Atovaquone
  • Pentamidine aerosol

If you get PCP once, you are more likely to get it again. Each time you get it, it causes damage to your lungs and your body can suffer side effects from the drugs.

You may have heard of a pneumonia vaccine, but it only protects you from a different kind of pneumonia. It will not prevent you from getting PCP.

RESOURCES:

AIDSinfo
http://www.aids.info.nih.gov

AIDS Treatment Data Network
http://www.atdn.org

CDC National Prevention Information Network
http://www.cdcnpin.org

HIV/AIDS
Centers for Disease Control and Prevention
http://www.cdc.gov/hiv

National Center for Infectious Diseases
http://www.cdc.gov/ncidod

National Institute of Allergy and Infectious Diseases
National Institutes of Health
http://www.niaid.nih.gov

CANADIAN RESOURCES:

Canadian Health Network
http://www.canadian-health-network.ca

Canadian HIV/AIDS Information Centre
http://www.aidssida.cpha.ca

The Lung Association
http://www.lung.ca/pneumonia

References:

Beers MH, Fletcher AJ, Jones TV, et al. The Merck Manual of Medical Information . Second Home Edition. Merck Research Laboratories: Whitehouse Station, NJ; 2003.

Pneumocystis carinii pneumonia. Dynamed website. Available at: http://dynamedical.com/dynamed.nsf?opendatabase . Accessed September 19, 2005.

Pneumocystis carinii pneumonia (PCP) and HIV. American Academy of Family Physicians website. Available at: http://www.familydoctor.org/475.xml . Accessed September 19, 2005.

Pneumocystis pneumonia (PCP). Fact Sheet Number 515. AIDS InfoNet website. Available at: http://www.aidsinfonet.org . Accessed September 19, 2005.

Preventing PCP. AIDS Treatment Data Network website. Available at: http://www.atdn.org/simple/pcp/html . Accessed September 19, 2005.

You can prevent PCP: a guide for people with HIV infection. CDC: National Center for HIV, STD, and TB Prevention website. Available at: http://www.cdc.gov/hiv . Accessed September 19, 2005.



Last reviewed January 2008 by David L. Horn, MD, FACP

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.

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