Pneumocystis carinii pneumonia: the time course of clinical and radiographic improvement.

Objectives: The purpose of this study was to compare the time course of clinical and radiographic improvement in patients with Pneumocystis carinii pneumonia (PCP), and evaluate the usefulness of early follow-up chest radiographs (CXRs) in these patients.

Design: Retrospective, chart review.

Methods: The medical records of 36 episodes of confirmed PCP among 28 patients were reviewed. Clinical parameters of improvement were defined as follows: (1) a decrease in temperature by 0.5 degrees C, (2) a decrease in respiratory rate by 25%, and (3) a 2% improvement in arterial oxygen saturation, as measured by pulse oximetry, in the setting of an unchanged amount of supplemental oxygen or a reduction in supplemental oxygen. A patient was defined as clinically improving when all three of these criteria were met. All CXRs were graded by radiologists, specifically for the study, as normal or abnormal and improved, worsened, or unchanged from the initial CXR.

Results: Clinical improvement was noted during 30 of 36 episodes of PCP (83%) at a mean of 4.5 +/- 2.5 days (+/- SD). There was improvement in the CXR finding during the hospital stay during 15 of 36 episodes (42%), at a mean of 7.7 +/- 4.5 days. Radiographic resolution preceded clinical resolution in only four cases (11%). Excluding seven patients who received ventilatory support, the median number of CXRs per patient was four (range, two to nine CXRs).

Conclusion: We conclude that radiographic improvement of PCP lags behind clinical improvement.