Pneumocystis carinii pneumonia is an infection in the lungs caused by a fungus. This form of fungal pneumonia is an example of an opportunistic infection, appearing only in patients who have compromised immune systems, as healthy patients can fight the fungi off before they colonize the lungs. Treatment includes aggressive administration of medications and supportive care in the hospital if the patient experiences complications. Survival rates vary, depending on when the condition is caught and how compromised the patient's health is to begin with.
Many people naturally carry this fungal organism and do not get sick because their bodies are able to defend against it. This organism, along with many others, has lived with humans on the skin and in the body successfully for thousands of years and doesn't want to kill its host. In people with conditions involving the immune system, such as HIV/AIDS, or patients taking immunosuppressive drugs like cancer drugs or medications to prevent transplant rejection, the fungus can enter the lungs and cause an infection.
Classic symptoms of Pneumocystis carinii pneumonia include a high fever, a dry cough, and shortness of breath. Patients commonly lose weight and develop night sweats. An X-ray can reveal the intrusion of fungus into the lungs, and cultures may be used to confirm the causative organism. Treatments include steroids in the short term to prevent inflammation, and a longer course of antifungal or antibiotic medication to kill the fungi. People with a history of drug reactions should make sure their doctors know about them so an appropriate medication is prescribed.
Some Pneumocystis carinii pneumonia patients need to be hospitalized for care during treatment. They may have such difficulty breathing that they require supplemental oxygen or mechanical ventilation to survive while the treatment takes effect. Patients can also have other complications such as organ damage or health problems caused by other opportunistic infections, like oral thrush, where yeast colonize the mouth. Patients with comorbidities, a formal term for “additional medical problems,” have a reduced chance of survival as their bodies are already under stress. These patients may require intensive care, and the prognosis can be poor.
Although people call it Pneumocystis carinii pneumonia, this name is actually incorrect. The causative organism has been renamed to Pneumocystis jiroveci, and technically this condition should be called Pneumocystis jiroveci pneumonia. Some people avoid the confusion over the name by using the acronym PCP, which once referred to Pneumocystis carinii pneumonia, but could also stand for Pneumocystitis jiroveci pneumonia.