ABSTRACT
Background: Lithium is routinely used to treat mania and other psychiatric disorders. It prevents the mood swing changes in bipolar disorders and the treatment is usually prolonged. Aim of current study was to observe histological changes in the thyroid gland of lithium carbonate treated albino rats. Methods: Sixty albino rats were taken and divided into two groups, group A (control group) of 15 animals, were fed with normal diet and group B of 45 animals, were fed normal diet along with lithium carbonate at the dose of 30mg/kg body weight daily. The animals were sacrificed at four, eight and twelve week’s interval, 5μm sections prepared and stained with haematoxylin and eosin stain. Results: Microscopic changes in thyroid gland of albino rats were evident after 8 weeks of drug administration which include marked pleomorphism, shrinkage in size of thyroid follicles, excess of colloid and marked vacuolations in acini. At 12th week of study, follicles were found both macro and micro follicular, with variable lining epithelium and hyperchromatic nuclei. Lining epithelium of some follicles was disrupted. The stroma was infiltrated with lymphocytes and eosinophils and there were some interfollicular hemorrhages. Conclusions: Lithium given over prolonged period will cause macro and micro follicular goiter with hyperplastic epithelium and hyper chromatic nuclei, hyperplasia of stroma with increased vascularity, sometimes hemorrhages and finally may lead to thyroiditis like picture. So, it is advised that patients on lithium therapy should be periodically evaluated for thyroid dysfunction.