Can thyroid volume predict thyroid dysfunction in patients with systemic sclerosis? A prospective cross-sectional study from a tertiary care center in North West India.

Previous studies have documented an association between thyroid dysfunction, predominant hypothyroidism, and antibody positivity in patients with systemic sclerosis (SSc). There are no studies reporting the relationship between thyroid volume and thyroid functions in patients with SSc. This study was conducted to correlate thyroid dysfunction with thyroid volume as measured on ultrasound and antibody positivity. Complete thyroid workup was done in 106 patients of SSc which included thyroid function test, antithyroid peroxidase (TPO) antibody, antithyroid-stimulating hormone receptor (TSHR) antibody, antithyroglobulin antibody, and thyroid ultrasound to assess thyroid volume, echogenicity and blood flow, and fine needle aspiration cytology of suspicious thyroid lesions. Prevalence of subclinical hypothyroidism was 8.5 %, overt hypothyroidism 1.9 %, subclinical hyperthyroidism 2.8 %, and overt hyperthyroidism in 0.9 % of the patients. Antithyroid peroxidase antibody was positive in 16 %, anti-TSH receptor antibody in 5.7 %, and antithyroglobulin antibody in none of the patients. Thyroid volume was in the range of atrophy (<4.5 ml) in 57.5 % patients, echogenicity altered in 15.1 %, and blood flow increased in 15.1 %. Thyroid volume correlated strongly with the pulmonary function test (FEV1). Routine thyroid ultrasound and thyroid function tests may be included in the workup of patients with SSc for the early detection of hypothyroidism since a small but significant percentage of patients developed thyroid dysfunction. Antithyroid antibodies may not correlate with the thyroid functions and hence should not be recommended.