Chronic irritation and cough occurring in asthma and chronic obstructive pulmonary disease (COPD) may weaken the airway walls, damage elastic fibers and contribute to excessive dynamic airway collapse known as tracheobronchomalacia (TBM). The prevalence of TBM in patients with asthma or COPD has not been extensively studied. The symptoms of these conditions often overlap, making the diagnosis challenging.
A retrospective analysis of the prevalence of TBM detected by CT scanning of the chest in patients diagnosed with asthma or COPD from January 1, 2007 to December 31, 2007 was conducted. CT records of these patients were assessed for excessive collapse of the trachea and main bronchi between the thoracic inlet and carina. The axial diameter of the lumen at the site of maximal collapse of the airway was measured and compared to a diameter at an adjacent site without collapse. We defined a 50% reduction in the airway lumen diameter as the criteria to diagnosis TBM.
Two hundred and eighty five patients had undergone CT scanning of the chest for various reasons; 130 were diagnosed with asthma and 155 with COPD. There were 25 (8.77%) patients who showed evidence of TBM on CT scanning of the chest; twelve diagnosed with asthma and thirteen with COPD. The age range was 39–99 years, with M:F ratio of 9:16. Eleven patients were white, six black and eight Hispanic. The most common reason for CT scanning of the chest was shortness of breath, seen in 22 (88%) patients. Ten patients were suspected of having a pulmonary embolism. Wheezing was observed in a fifth of our patients.
A significant subgroup of patients with a diagnosis of asthma or COPD have features of TBM on conventional CT scanning of the chest.
A diagnosis of TBM should be considered in patients with symptoms of cough or dyspnea, refractory to standard therapy for asthma or COPD.
Rubal Patel, No Financial Disclosure Information; No Product/Research Disclosure Information