Ankylosing spondylitis lung disease--an underdiagnosed entity?

During the last 10 years, 14 cases of ankylosing spondylitis (AS) with upper lobe changes were diagnosed. This is certainly an underestimation, since AS is often not noted in the case records even when diagnosed. Two recent cases were earlier undiagnosed, and only on specific questioning did the patients admit symptoms, though they were both HLA B27 positive and had X-ray changes of the sacro-iliacal joints typical of the disease. Thus, if not carefully sought, the diagnosis can be missed. A literature review revealed 160 published cases. The lung lesions can be complicated by superinfections of fungi or non-tuberculous mycobacteria or even mycobacterium tuberculosis.