Bronchiolitis obliterans in the 1990s in Korea and the United States

Study objectives: Our current knowledge of pediatric bronchiolitis oblitera ns (BO) is based largely on a few small series of patients that were report ed in the older literature. In these older cases, the mortality rate was hi gh. This study was conducted to investigate the characteristics of pediatri c BO cases in two different countries. Design: We extracted specific information regarding predisposing factors, s ymptoms and signs, diagnostic studies, treatment, and outcome from the medi cal records of 31 children who received diagnoses of BO at four university medical centers in Korea and the United States in the 1990s. Results: The large number of Asian children reflects a clustering of cases in Korea due to adenovirus and Mycoplasma pneumoniae epidemics. The charact eristic diagnostic features of BO were present in 29 of 30 high-resolution CT (HRCT) studies. Seven of nine children who underwent biopsies had histol ogic confirmations of BO. In two patients whose biopsy results were nondiag nostic, the diagnosis was established by HRCT together with pulmonary funct ion testing results that were consistent with nom-eversible small airways o bstruction. Fifteen children (48.4%) had evidence of hypoxemia. At present, all but one are alive. Patients with elevated severity-of-illness scores w ere observed to have increased likelihoods of lung transplantation or death . Conclusions: We conclude that BO has a good overall prognosis and that the mortality rate has declined over the past decade. This could be related pri marily to the use of HRCT for accurate diagnosis and the availability, of p ediatric lung transplantation. BO cases in Korea were associated with infec tious epidemics, whereas those in United States had variable predisposing f actors.