Signs may include delayed relaxation of the ankle reflex and a slow heartbeat. A goiter may be present with a completely enlarged thyroid gland; sometimes only part of the thyroid is enlarged and it can be knobby. Related disorders
Thyroid hormone abnormalities are common in major psychiatric disorders including bipolar disorder; clinical research has shown there is a high rate of thyroid dysfunction in mood disorders and schizophrenia-spectrum disorders, concluding that there is a case for screening for the latter among people with thyroid illness. Causes
Hypothyroidism is caused by inadequate function of the gland itself (primary hypothyroidism), inadequate stimulation by thyroid-stimulating hormone from the pituitary gland (secondary hypothyroidism), or inadequate release of thyrotropin-releasing hormone from the brains hypothalamus (tertiary hypothyroidism). Primary hypothyroidism is about a thousandfold more common than central hypothyroidism.Iodine deficiency is the most common cause of primary hypothyroidism and endemic goiter worldwide. In areas of the world with sufficient dietary iodine, hypothyroidism is most commonly caused by the autoimmune disease Hashimotos thyroiditis (chronic autoimmune thyroiditis). Hashimotos may be associated with a goiter. It is characterized by infiltration of the thyroid gland with T lymphocytes and autoantibodies against specific thyroid antigens such as thyroid peroxidase, thyroglobulin and the TSH receptor.After women give birth, about 5% develop postpartum thyroiditis which can occur up to nine months afterwards.
Treatment is with thyroid hormone replacement.Other species that are less commonly affected include cats and horses, as well as other large domestic animals. In cats, hypothyroidism is usually the result of other medical treatment such as surgery or radiation. In young horses, congenital hypothyroidism has been reported predominantly in Western Canada and has been linked with the mothers diet. References
External links
Hypothyroidism at Curlie
"Hypothyroidism information for patients". American Thyroid Association. Retrieved 2017-03-25. "UK Guidelines for the use of thyroid function tests" (PDF). The Association for Clinical Biochemistry, British Thyroid Association and British Thyroid Foundation. 2006. Retrieved 2013-12-25. Alexander EK, Pearce EN, Brent GA, Brown RS, Chen H, Dosiou C, Grobman WA, Laurberg P, Lazarus JH, Mandel SJ, Peeters RP, Sullivan S (March 2017). "2017 Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and the Postpartum". Thyroid. 27 (3): 315–389. doi:10.1089/thy.2016.0457. PMC 3472679. PMID 28056690.