AIDS Pneumonia (PCP)
Oct 28, 1996
What is PCP? How does it differ from other pneumonia? What is the course of the infection and recommended treatment?
Response from Dr. Cohen
PCP stands for Pneumocystis carinii pneumonia. Technically, Pneumocystis carinii is a fungus, but until recently it was always thought to be a parasite. Because it acts more like a parasite and responds to some antiparasitic drugs but not to antifungal drugs, for all practical purposes, it's a parasite.
PCP differs from other pneumonias (which are usually caused by common bacteria) in the following ways:
PCP require greater immune suppression: usually a CD4 count less than 200. Bacterial pneumonias can occur at any stage of disease. PCP is more gradual in onset. It typically comes on over weeks, while bacterial pneumonia comes on over days. Shortness of breath is usually more pronounced with PCP. With other types of pneumonia, cough tends to be a bigger problem than shortness of breath. The cough of PCP is usually a dry cough, whereas people with bacterial pneumonia cough up lovely gobs of yellow or green or brown sputum. Bacterial pneumonias tend to respond faster to treatment. With PCP, people often get worse for a few days before the medicines kick in. The x-ray appearance of PCP is usually different. With PCP you see involvement of both lungs, whereas with bacterial pneumonia only certain sections of the lung may be involved People with bacterial pneumonia often have chest pain when they breathe. That is not common with PCP.
Those are generalizations: it can often be quite difficult to tell the difference between PCP and other types of pneumonia.
PCP is usually treated for 21 days. The drug of choice is trimethoprim-sulfamethoxazole (Bactrim or Septra), given at fairly high doses. For people who can't take sulfa drugs, there are a number of alternatives. Trimethoprim plus dapsone or clindamycin plus primaquine can also be given. Atovaquone (Mepron) is not quite as effective, but it is well-tolerated. For people with severe PCP who can't take sulfa drugs, pentamidine can be used. It's fairlytoxic, which is why we tend to save it for people with life-threatening pneumonia. Trimetrexate can also be used in such situations, but it is not as effective as trimethoprim-sulfamethoxazole. People who have moderate to severe PCP should also receive steroids (prednisone), which improves the prognosis and helps to prevent lung damage.
Of course, it's better to prevent PCP than to treat it, which is why everyone with a CD4 count of 200 or less should be on PCP prophylaxis.
I should also point out that there are other types of HIV-related pneumonia that I haven't discussed, but PCP and bacterial pneumonia are the most common.
Get Email Notifications When This Forum Updates or Subscribe With RSS
This forum is designed for educational purposes only, and experts are not rendering medical, mental health, legal or other professional advice or services. If you have or suspect you may have a medical, mental health, legal or other problem that requires advice, consult your own caregiver, attorney or other qualified professional.
Experts appearing on this page are independent and are solely responsible for editing and fact-checking their material. Neither TheBody.com nor any advertiser is the publisher or speaker of posted visitors' questions or the experts' material.