Thyroid involvement in patients with active inflammatory bowel diseases

Previous studies have documented an association between systemic diseases and disorders of the thyroid gland, expressed by an enlargement of the thyroid and by the presence of anti-thyroid antibodies. Chronic inflammatory bowel diseases (IBD, ulcerative colitis and Crohn's disease) may also present a multi-organ involvement, including the biliary tree, joints and uvea. To detect a possible subclinical thyroid involvement, thyroid volume and function were assessed in 31 patients with IBD in active phase and in 50 control subjects. Thyroid volume was calculated by ultrasonography on the basis of the three maximum diameters of the 2 lobes. A blood sample was taken to determine free thyroid hormones, TSH, and anti-thyroid antibodies. In patients with IBD, thyroid volume was increased on average by 35%, and the prevalence of thyroid enlargements (antero-posterior diameter > 20 mm) was 3 times higher (45% vs 16%). Free thyroxine was increased by nearly 50%, but only 10% of patients had anti-thyroid antibodies. Alterations of thyroid volume and function are present in IBD, even in the absence of clinically-detectable thyroid disease. The association of IBD with thyroid disorders, as well as the involvement of various organs, confirms the view that IBD is a systemic disease.