Serial Changes in Pulmonary Function Testing in A Patient with Tracheobronchial Amyloidosis: Relevance for Early Diagnosis

Abstract

Amyloidosis is a disease of abnormal extracellular deposition of proteins within tissues, commonly affecting solid organs such as the heart, liver, and kidneys. Less commonly, amyloidosis may affect the proximal tracheobronchial tree. Clinical symptoms are vague and may include shortness of breath, stridor, hoarseness. Pulmonary function testing at the time of diagnosis usually reveals an obstructive pattern. Diagnosis is difficult, and patients with tracheobronchial amyloidosis are frequently misdiagnosed with asthma or chronic obstructive pulmonary disease. Early changes in pulmonary function testing in patients with tracheobronchial amyloidosis have not been described. We present a case of a firefighter who with obstructive symptomatology who was subsequently diagnosed with proximal tracheobronchial amyloidosis. As a component of his occupational health surveillance, yearly examinations and pulmonary function testing had been performed. Serial pulmonary function testing dating back fourteen years prior to diagnosis reveal an early decrease in peak expiratory flow. Over time and in retrospect, progressive blunting of the expiratory limb of his flow-volume loops is identified beginning ten years prior to presentation. These changes significantly predated his clinical symptomatology and may be useful for early identification of patients with tracheobronchial amyloidosis. The relationship between chronic smoke inhalation and the development of tracheobronchial amyloidosis is unclear.