Course of pulmonary dysfunction in children surviving Pneumocystis carinii pneumonitis. A prospective study.

Pulmonary function studies were done serially in 23 children 7 to 18 yrs of age who had survived the acute stage of Pneumocystis carinii pneumonitis. Each child was asymptomatic. Spirometric indices, expiratory flows, pulmonary gas transfer factor, arterial blood gases, and other clinical variables were assessed a few days before patients were discharged from the hospital and at 1-, 3-, 6-, and 12-month intervals thereafter; two patients developed recurrent pneumonitis during follow-up and were studied twice. All but five subjects had pulmonary dysfunction when tested initially. A decrease in pulmonary gas transfer factor, observed in 17 studies, was the most common abnormality. Restrictive pulmonary disease was seen in 11 studies; an obstructive component, in one. Arterial hypoxemia at rest, while patients were breathing room air, was noted in nine cases. Roentgenographic evidence of bilateral diffuse lung opacities was seen in 11 patients and was positively correlated with decreases in pulmonary gas transfer factor (p less than 0.001). Arterial hypoxemia was significantly related to intrapulmonary right-to-left shunt (p less than 0.001) but not to decreases in pulmonary gas transfer factor, indicating the importance of ventilation-perfusion abnormalities in these patients. Serial follow-up studies disclosed significant improvement in pulmonary function deficits within 1 month and complete resolution by 6 months in all survivors. Recovery was not related to the amount of duration of O2 therapy, to the need for ventilatory support, or to chest roentgenographic abnormalities. Histopathologic findings in nine patients who died during follow-up did not indicate any residual interstitial fibrosis, collagen deposits, or alveolopathy. We conclude that Pneumocystis carinii pneumonitis during childhood does not typically produce long-lasting pulmonary sequelae.