Preface

Hypothyroidism is a common endocrine disorder. It is treated with the synthetic thyroid hormone that mimics the natural hormone produced by the thyroid gland. The disease may be the result of many disorders; however, Hashimoto's thyroiditis is the most common cause. Nowadays, an epidemic of autoimmune diseases may have had an impact on the incidence of Hashimoto's thyroiditis. As such, there is renewed interest in the etiology of Hashimoto's thyroiditis. Moreover, new developments, such as the advent of immune checkpoint inhibitors in the treatment of cancer, have had an impact on the treatment of hypothyroidism in these patients. Therefore, there is renewed interest and new developments in hypothyroidism. This book discusses these advances.

The first section focuses on the etiology and pathogenesis of hypothyroidism. The first chapter in this section discusses different aspects of hypothyroidism and autoimmune thyroiditis with an emphasis on the etiology and pathogenesis of autoimmune Hashimoto's thyroiditis. The second chapter discusses the application of precision medicine tools in the detection, diagnosis, and treatment of thyroid dysfunction. The third chapter reviews different aspects of the morphology of the thyroid gland and the etiology of hypothyroidism. The fourth chapter examines the role of ultrasound in the evaluation of hypothyroidism. The fifth and final chapter in this section describes the role of melatonin in the modulation of thyroid function in an experimental model.

The second section discusses the treatment of hypothyroidism, including severe life-threatening hypothyroidism.

The third section examines the effect of hypothyroidism on various organ systems. The first chapter in this section describes the effect of hypothyroidism on fertility in women. The second chapter discusses the effect of iodine and iodinated amino acids analogous to vertebrate thyroid hormones on sea organisms. The third chapter evaluates glucose metabolism in normal and neoplastic thyroid cells.

This book is the result of the efforts of a group of experts in thyroid physiology and thyroid disease. I gratefully acknowledge the work of the contributing authors. I also wish to thank Kristina Kardum Cvitan and Zrinca Tomicic for their help throughout the publication process.

Last, but not least, I dedicate this book to my mother, Areti, whose example and efforts made it possible for me to become the editor of this book.

#### **Ifigenia Kostoglou-Athanassiou, MSc, MD, Ph.D.** Endocrinologist, Department of Endocrinology, Asclepeion Hospital, Voula, Athens, Greece

### Section 1
