CARINII

About Your Diagnosis
Pneumocystis carinii is a fungus that causes pneumonia only in individuals with impaired immune system function. It is a common cause of pneumonia in those with the human immunodeficiency virus (HIV), especially when the CD4 count (a type of immune system cell injured by HIV) drops below 200 mm3. Others susceptible to Pneumocystis carinii pneumonia include those receiving cancer chemotherapy, long-term prednisone therapy, or immunosuppressant drugs to prevent transplant organ rejection, as well as those with rare inherited disorders of immunity. It remains unclear how Pneumocystis carinii pneumonia develops. Either the organism is spread person to person or lies dormant for years and then reactivates when the immune system is suppressed. There is no vaccine, but certain drugs can help prevent the development of Pneumocysitis pneumonia.

Living With Your Diagnosis
Symptoms usually develop slowly, and gradually become more severe over time. The most common symptoms are shortness of breath, dry cough, and fever. Chest x-rays and blood tests help to assess the severity of the illness. Specialized testing is required to diagnose Pneumocystis infection. The initial test is usually inspection of the sputum for Pneumocystis. If this test is inconclusive, then bronchoscopy is performed. During this procedure, your doctor inspects your lungs with a lighted tube guided through your nose or mouth. Lung fluids are collected and biopsy specimens may be taken. If Pneumocystis is present, it will be found by bronchoscopy in 90% of cases. Rarely, a surgical lung biopsy is required to confirm the diagnosis. Pneumocystis is a serious, potentially life-threatening illness. More than 50% of patients will survive if treated with effective drugs, although the survival rate is lower in patients with more severe immune system dysfunction. Pneumocystis can recur after therapy if preventive drugs are not used.

Treatment
The combination of trimethoprim/sulfamethoxazole (TMP/SMX) is usually the drug of first choice. Other drugs are available, such as pentamidine, for
those who are allergic to sulfa or who fail to improve with TMP/SMX. Symptoms may actually worsen during the first 2–4 days of treatment. Therapy is usually administered for up to 21 days. Steroids are used in severe cases to help reduce lung inflammation associated with infection. Trimethoprim/sulfamethoxazole can be given either orally or intravenously. Milder cases can be treated on an outpatient basis. More severely ill patients are hospitalized for other supportive measures, such as supplemental oxygen. Mechanical ventilation in an intensive care unit may be used if the lungs temporarily are unable to adequately take up oxygen and expel carbon dioxide. The most common side effects of TMP/SMX include rash, nausea, fever, and low white blood cell counts. Oral TMP/SMX is also very effective at preventing Pneumocystis carinii pneumonia. It is administered as infrequently as one tablet three times per week, but many individuals take it daily so as not to forget the medication. If you fit into any of the following groups, you should receive this preventive therapy.
• Patients who are HIV positive.
• Patients with CD4 counts less than 200 mm3.
• Patients who have had a previous episode of Pneumocystis carinii pneumonia.
• Patients receiving long-term steroid therapy or other immunosuppressant drug therapy.

The DOs
• Take your prescription medications exactly as prescribed. Complete all courses of antibiotics.
• Use nonprescription cough suppressants as needed.
• Use acetaminophen or aspirin (except in children) to suppress fever and treat pain.
• If you are HIV positive, see your health care provider regularly for monitoring of immune function.

The DON’Ts
• Home treatment of Pneumocystis carinii pneumonia with antibiotics should be avoided if the home environment is not stable and conducive to rest and recovery.

When to Call Your Doctor
• If you suspect Pneumocystis carinii pneumonia because of a new fever, cough, or shortness of breath.
• If your symptoms worsen despite the prescribed therapy.
• If an unexplained rash develops (may signal a drug allergy).
• If nausea prevents you from taking the prescribed medications.

Websites:
American Lung Association
www.lungusa.org