Airway inflammation and lung function decline in childhood post‐infectious bronchiolitis obliterans

Abstract

Post-infectious bronchiolitis obliterans (PBO) is a rare form of chronic obstructive lung disease in children with few data on the pulmonary function outcome and underlying inflammatory process. The aim of this study was to determine the change in lung function over time and to investigate by bronchoalveolar lavage (BAL) the inflammatory characteristics of pulmonary involvement. Eleven Caucasian children with PBO were evaluated to estimate the average rate of change in lung function indices using a mixed model. The differential cytology and lymphocyte subsets of BAL fluid were analyzed. The median follow-up was 10.2 (IQR 3.2-12) years. The estimated forced expiratory volume in 1 sec (FEV1) had a baseline intercept of 57% predicted (62% predicted after bronchodilator) at 10 years of age which fell at a rate of 1.01% per year whereas the estimated forced expiratory flow 25-75 (FEF25-75) had a baseline intercept of 36% predicted (42% predicted after bronchodilator) at 10 years of age which fell at a rate of 1.04% per year. The estimated FEV1/FVC ratio had a baseline intercept of 70% (74% after bronchodilator) at 10 years of age which declined with an average slope of 1.02% per year (-1.10% per year after bronchodilator). Although the baseline and post-bronchodilator level of estimated FVC was abnormal (68% and 69% predicted, respectively) it did not change significantly with time. The median disease duration at BAL evaluation was 3.7 (IQR 0.7-8) years. The percentage differential cell counts were characterized by a significant increase in neutrophils (median 50%, IQR 1-66%), and a slight increase of lymphocytes (median 14%, IQR 7.5-15%). In conclusion, pulmonary function in childhood PBO is characterized by significant airway obstruction which deteriorates over time. The presence of an ongoing inflammatory process could explain the decline in lung function over time.

Post-infectious bronchiolitis obliterans in children

“…Esses achados foram encontrados anos após a injúria pulmonar, sugerindo que existe manutenção do processo inflamatório 34 .…”

“…Em estudo que avaliou crianças que apresentaram pneumonia por adenovírus, 65% apresentaram padrão obstrutivo na espirometria após cerca de 13 anos 12 . Existem relatos de manutenção do padrão obstrutivo de forma inalterada ao longo do tempo 28 , mas também de queda lenta e progressiva dos valores espirométricos 34 . Em um estudo com 11 crianças com BOPI, foi observada uma queda de 1,02% ao ano do valor de VEF 1 /CVF, de 1,01% ao ano do VEF 1 e de 1,04% ao ano do FEF 25-75% 34 .…”

“…Alguns autores defendem a ideia de que ocorre uma manutenção do processo inflamatório após a lesão aguda nas vias aéreas, o que justificaria a persistência dos sintomas 28 , a recorrência das anormalidades radiológicas 29 e a alteração persistente da função pulmonar 34 .…”

Bronquiolitis obliterante post-infecciosa: características y seguimiento a mediano plazo de 21 casos en Bogotá-Colombia a 2640 m de altura

“…6 Nuestros resultados coinciden con lo publicado que indica que la bronquiolitis obliterante postinfecciosa es una enfermedad compleja, que implica altos costos y que tiene importantes implicaciones emocionales. [1][2][3][4][5][6][7][8]10,11 En el presente estudio encontramos obstrucción significativa de la vía aérea en 7/9 casos con un volumen espiratorio forzado en el primer segundo (VEF1) que osciló entre el 35% al 62% del predicho. Datos similares, indicando un compromiso significativo de la función pulmonar, se encontraron en la mayoría de 77 casos en Brasil, 5 de 46 en Argentina 17 y de 11 en Italia.…”

“…[1][2][3][4][5][6] La frecuencia de esta patología tiene importantes variaciones regionales en el mundo; se ha reportado principalmente en Argentina, Chile y Brasil, [1][2][3][4][5][6] y en menor proporción en Malasia, 7 China, 8 Turquía 9 y Europa. 10,11 Todos los estudios de seguimiento de bronquiolitis obliterante post-infecciosa se han hecho a nivel del mar o en baja altura. No encontramos en la literatura publicaciones previas de seguimiento de casos de esta patología en alturas por encima de los 2500 metros.…”