Hypothyroidism is a decreased activity of the thyroid gland which may affect all body functions. The rate of metabolism slows causing mental and physical sluggishness. The most severe form of hypothyroidism is myxedema, which is a medical emergency.
Review Date 6/14/2018
Updated by: Brent Wisse, MD, Associate Professor of Medicine, Division of Metabolism, Endocrinology & Nutrition, University of Washington School of Medicine, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.