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Dysanaptic growth of lung and airway in children with post-infectious bronchiolitis obliterans

Authors


  • Authorship and contributorship

    All authors listed meet definition of authorship.

  • Ethics

    The study was reviewed and approved by the University of Texas Medical School at Houston institutional review board prior to initiation of this retrospective chart review.

  • Conflict of interest

    The authors have disclosed no potential conflicts of interest. No funding was obtained.

Abstract

Rationale

Post-infectious bronchiolitis obliterans (PBO) is a rare form of chronic obstructive lung disease associated with small airway fibrosis following a severe insult to the lower respiratory tract. It has been suggested that PBO is a non-progressive disease. However, evidence supporting this statement is limited. In this case series, we sought to determine the changes of pulmonary function tests (PFT) over time in children with PBO.

Methods

Seven children with PBO, ages 6–15 years old, were retrospectively studied between 1994 and 2012. Spirometry and lung volumes tests were performed in accordance with American Thoracic Society (ATS) guidelines and were monitored over time. The average rate of change was calculated using generalized linear mixed models.

Results

The median baseline values for forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), the FEV1/FVC ratio and forced expiratory flow 25%–75% (FEF25%–75%) were 57%, 50%, 87% and 29%, respectively. FVC increased at a rate of 1.8% per year (P = 0.008). There was no significant change in FEV1 over time (P = 0.112). However, the FEV1/FVC ratio decreased by 2.6% per year (P < 0.001).

Conclusion

PFT in childhood PBO was characterized by significant airway obstruction. Over time, FVC (lung parenchyma) increased and FEV1 (airway) remained stable, but FEV1/FVC ratio declined more than expected, suggesting a mismatch in the growth of the airway and lung parenchyma (dysanaptic growth). Further studies in larger populations are needed to validate these observations.

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