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New Treatments for Pneumocystis Carinii Pneumonia

Pneumocystis carinii pneumonia (PCP) usually occurs at CD4 counts of less than 200 cells/mm3. The risk increases as the CD4 cell count declines, with a small proportion of cases occurring at CD4 counts higher then 200, and a greater risk of PCP at CD4 counts below 100. Transmission occurs by the respiratory route.

Diagnosis

Symptoms of PCP include progressive dyspnea, nonproductive cough, fever, night sweats, and fatigue. A productive cough may sometimes be noted.

Risk Factors for PCP. CD4 <200/mm3, oropharyngeal thrush, unexplained fever >2 weeks, prior Pneumocystis carinii pneumonia, AIDS defining illness (TB, Kaposi's sarcoma), prior bacterial pneumonia, HIV wasting.

Physical exam findings may include cyanosis (39%) and rales (33%).

Diagnostic Procedures

Chest x-ray usually reveals diffuse, interstitial infiltrates that may progress to a diffuse alveolar process; however, x-ray findings can Pneumocystis Carinii Pneumonia PCP AIDS HIV often be normal or atypical.

Induced Sputum Stain. If performed properly, induced sputum examination can diagnose 85-95% of cases of PCP. Fluorescent monoclonal antibody staining is highly specific.

Bronchoalveolar lavage (BAL) should be performed in patients in whom the level of suspicion for PCP is high and in whom induced sputum examination is negative.

Diffusion Capacity for Carbon Monoxide (DLCO) may be useful when PCP is suspected but the chest x-ray is normal or atypical.

High Resolution CT Scan: Absence of typical changes (ie, ground glass opacities) on this test may be useful to exclude PCP, but results may be falsely positive.

Treatment of Pneumocystis Carinii Pneumonia

Trimethoprim-sulfamethoxazole (TMP-SMX, Bactrim, Septra)

TMP-SMX is first choice therapy; IV therapy consists of 15 mg of trimethoprim component/kg/d in 3 divided doses x 21 days (20 mL of IV solution in 250 mL of D5W IVPB q8h) [solution for injection: 80/400 mg/5 mL]

Oral therapy consists of two double strength tabs q8h for 21 days.

Dapsone/Trimethoprim (DAP/TMP)

  1. This regimen is the second choice therapy if the patient can not tolerate, or fails to respond to, TMP-SMX. This regimen is appropriate in patients who are not acutely ill and who can tolerate oral drugs.
  2. Dapsone, 100 mg PO and trimethoprim.