Autoimmune thyroiditis – Correlation between thyroid hormone status and AMA titre

Background: Thyroiditis is the second most common thyroid lesion next to endemic goitre diagnosed on FNA in iodine (I2) deficient areas. This study was carried out to study correlation between thyroid hormone status with anti-thyroid antibodies in cases of autoimmune thyroiditis diagnosed on FNAC. Aim: To correlate thyroid hormone status with anti-thyroid antibodies in cytologically diagnosed cases of autoimmune thyroiditis. Materials and methods: This was a retrospective study carried out in a tertiary care teaching hospital. 150 cases diagnosed as autoimmune thyroiditis in a two year period from January 2010 to December 2011 formed the study group. The clinical history, TFT, and AMA tires were noted from the medical record available with the patient and also from Endocrinology department records. Results: Incidence of autoimmune thyroiditis was found to be 13.4%. Majority of the patients were females (96.7%), 53.3% of cases were seen in the age group 21-40 years age group. Of the patients with autoimmune thyroiditis, 110(73.3%) patients were euthyroid while 32 (21.3%) patients were hypothyroid at the time of FNAC. Only 8(5.3%) patients showed evidence of hyperthyroidism. 8% patients showed subclinical hypothyroidism. In 97 patients anti-microsomal antibody titre (AMA) was available, 83 were positive i.e.85.6% positivity. Of the cytologically diagnosed cases of autoimmune thyroiditis, 14.4% cases showed AMA negativity. Thus FNAC remains the gold standard for the diagnosis. Conclusion: Autoimmune thyroiditis was seen more commonly in females, majority cases were seen in age group of 21-40 years. Euthyroid autoimmune thyroiditis was common in our study. Anti-microsomal antibody titre (AMA) was available in 97 cases, out of which 83 were positive i.e.85.6% positivity. Of the cytologically diagnosed cases of autoimmune thyroiditis, 14.4% cases showed AMA negativity. Thus FNAC remains the gold standard for the diagnosis in subjects with a clinical diagnosis of Hashimoto's thyroiditis and negative antibody results.