A 23-year-old man presents to the clinic for assessment of a gradual but progressive increase in breathing difficulty. He mentions a long history of back pain with prolonged morning stiffness. His past medical history is also significant for an episode of iritis in the past.On physical examination, the pertinent findings are a reduced range of motion in the lumbar spine with forward flexion and pain on palpation of the sacroiliac joint and surrounding soft tissue. X-rays of the pelvis show erosions and sclerosis of the sacroiliac joint. Which of the following is the most likely pulmonary complication of this condition?
High-Yield Explanation
Ankylosing spondylitis (AS) is characterized by bilateral upper lobe fibrosis, which may be complicated by fibro cavitary disease. The pulmonary involvement is rare and is usually very slowly progressive. The cavities can be colonized by Aspergillus. Airflow obstruction is not a usual feature of AS and suggests an alternate diagnosis such as asthma or COPD. Hilar adenopathy, pleural effusions, and chronic PE are also not characteristic of AS.