Subclinical alveolar involvement in ulcerative colitis

Background: Although pulmonary dysfunction has been described in patients with ulcerative colitis (UC), the pathogenesis remains unclear. Our aim was to study alveolar ephitelial damage using technetium-99m diethylene triamine penta acetic acid (Tc-99m DTPA) aerosol scintigraphy in patients with UC but without respiratory symptoms. Methods: We enrolled 32 patients (18 women and 14 men; mean age, 36.4 ± 11.6 yr) with active UC, 10 patients with inactive UC (6 women and 4 men; mean age, 43.4 ± 11.8 yr), and 31 healthy controls (24 women and 7 men; mean age, 40 ± 10 yr). Tc-99m DTPA aerosol scintigraphy was performed on all patients and controls. The relationship between alveolar ephitelial permeability and the activity, localization, and duration of the disease was studied. Results: There was a significant difference between alveolar ephitelial permeability results in patients with active UC and those of the controls (P < 0.001). The same correlation was also found between the patients with inactive UC and the control group (P < 0.001). There was no correlation between Tc-99m DTPA alveolar scintigraphic test results and the stage of activity, localization, and duration of the disease. Conclusions: A latent pulmonary involvement may exist in patients with active and inactive UC. The alveolar involvement may be the earliest pulmonary damage, and a DTPA clearance test may show the early changes in pulmonary ephitelial permeability that precedes clinical symptoms. Increased alveolar ephitelial permeability is an extraintestinal manifestation in patients with UC and is not related to the activity of the colitis.