A 35-year-old woman who had an allogeneic BMT 10 years ago for pre-B ALL complicated by GVHD of the skin (controlled with topical steroids) presents to the ED with several months of worsening dyspnea. PFTs done a month ago revealed FEV1 of 24% predicted, FVC of 70% predicted, and FEV1/FVC of 0.35. She is afebrile, normotensive, and not hypoxemic but becomes severely dyspneic with mild activity. Chest X-ray is clear. High-resolution chest CT reveals mosaic perfusion and evidence of extensive air-trapping on expiratory views.
Which of the following statements is correct?A. Lung biopsy is indicated
Correct Answer: C
This patient suffers from postallogeneic stem cell transplant bronchiolitis obliterans syndrome (BOS) resulting from the destruction of small airways by scarring inflammation, a form of chronic GVHD in the lung. A similar disease occurs in lung transplant patients (mismatch between lung and immune system). Patients may present with symptoms of moderate to severe airflow obstruction, though many patients postallogeneic SCT have mild obstructive lung disease without symptoms. BOS is diagnosed based on new airflow obstruction (FEV1/FVC <0.7 with FEV1 <75% predicted) in the absence of acute infection, with the most specific feature on high-resolution CT of extensive air trapping. Lung biopsy is typically not pursued if imaging does not suggest an alternative diagnosis, especially if the patient has other evidence of GVHD. Although no high-quality RCT evidence exists, most clinicians prescribe inhaled glucocorticoids and beta-agonists. Unfortunately, BOS is often irreversible and lung transplantation is sometimes pursued. Extrapolating from the experience in lung transplant, some physicians used to administer azithromycin post-BMT for prophylaxis. However, a recent RCT showed harm, although there may still be a role for azithromycin in the treatment of newly diagnosed BOS.