A 57-year-old man underwent lung transplantation for severe emphysema 2 years ago. Over the last 6 months, he has had increasing exertional dyspnea and dry cough. The patient has adhered to his medical regimen. He does not smoke and has no exposure to secondhand smoke. Physical examination shows scattered bilateral rales and end-expiratory squeaks. Cardiac auscultation reveals no murmurs or additional sounds. Spirometry demonstrates markedly decreased FEV1 compared with findings 6 months prior, although the FVC remains largely unchanged. Chronic lung transplant rejection is suspected, and bronchoscopy with transbronchial biopsy is planned. Histopathology is most likely to show injury predominantly involving which of the following structures?

Question

A 57-year-old man underwent lung transplantation for severe emphysema 2 years ago.  Over the last 6 months, he has had increasing exertional dyspnea and dry cough.  The patient has adhered to his medical regimen.  He does not smoke and has no exposure to secondhand smoke.  Physical examination shows scattered bilateral rales and end-expiratory squeaks.  Cardiac auscultation reveals no murmurs or additional sounds.  Spirometry demonstrates markedly decreased FEV1 compared with findings 6 months prior, although the FVC remains largely unchanged.  Chronic lung transplant rejection is suspected, and bronchoscopy with transbronchial biopsy is planned.  Histopathology is most likely to show injury predominantly involving which of the following structures?

Quizplus · Accepted Answer

11ec160b_37b6_c9b1_9249_19a80dfac089_MD0001_00 Although patients who undergo organ transplantation receive immunosuppressive therapy, rejection reactions still commonly occur. The severity and timing of the rejection depends on the degree of difference between the donor and recipient major histocompatibility complex antigens in addition to other variables. Chronic lung transplant rejection is marked by submucosal lymphocytic inflammation in the walls of the small airways. Subsequent ingrowth of granulation tissue into the lumen leads to airway obstruction and obliteration (bronchiolitis obliterans). Patients usually present with slowly worsening dyspnea and dry cough that begins months or years after transplantation. Lung examination may reveal end-expiratory squeaks or pops, and spirometry typically demonstrates airflow limitation (obstructive pattern) with a drop in FEV1. Other forms of lung transplant rejection include: (Choice B) Bronchiolitis obliterans can occasionally cause large airway scarring, leading to bronchiectasis, but this is not the primary pathologic manifestation. (Choice C) Restrictive allograft syndrome, a less common type of chronic lung transplant rejection, can result in fibrotic changes to the pleurae. However, pulmonary function tests would reveal a restrictive (reduced FVC), not obstructive, pattern. Educational objective: Chronic lung transplant rejection is due primarily to progressive scarring of the small airways, leading to bronchiolitis obliterans. Manifestations occur months or years after transplantation and include obstructive lung disease (eg, reduced FEV1) with dyspnea and dry cough. __________ References: Chronic lung allograft dysfunction phenotypes and treatment. (http://www.ncbi.nlm.nih.gov/pubmed/28932572) Immunobiology of chronic lung allograft dysfunction: new insights from the bench and beyond. (http://www.ncbi.nlm.nih.gov/pubmed/19519813) Current views on chronic rejection after lung transplantation. (http://www.ncbi.nlm.nih.gov/pubmed/25857869)

A 57-Year-Old Man Underwent Lung Transplantation for Severe Emphysema 2