Hypothyroidism in Infants and Children

Hypothyroidism in Infants and Children: Glossary

Here are definitions of medical terms related to hypothyroidism in children.

Adam’s apple: This part of the cartilage that forms the larynx, or voice box, can be felt at the front of the neck. It is more prominent visually and by touch in men than in women.

Antibody: A protein made by the body’s immune system to defend the body against a foreign substance like a virus, bacterium, or other foreign body, most often a foreign protein. Rarely, the body’s immune system may mistakenly make antibodies against a part of the person’s own body. This is an abnormal or autoimmune response.

Antithyroid drug: Any one of several agents used to treat hyperthyroidism that hinders production of thyroid hormone within the thyroid gland.

Autoimmune disorder: An autoimmune disorder is one in which the body’s immune system mistakenly “attacks” its own healthy tissue.

Congenital: A term meaning ‘present at birth.’

Cretinism: A general term for hypothyroidism that occurs in infants.

Endocrine gland: A gland that releases a chemical messenger, known as a hormone, directly into the bloodstream, that will affect other parts of the body. The thyroid is an endocrine gland.

Endocrinology: The subspecialty within the field of internal medicine devoted to disorders of the endocrine glands; the specialist is called an endocrinologist.

Gene: The structure within a cell’s nucleus that carries inheritable information from one generation to the next.

Graves’ disease: An autoimmune disorder in which the immune system attacks the cells of the thyroid gland causing hyperthyroidism. Hyperthyroid eye changes and skin changes are sometimes associated with it.

Growth hormone: A chemical substance produced in the pituitary gland that, along with thyroid hormone, supports proper growth and development during childhood.

Hashimoto’s thyroiditis: An autoimmune disorder of the thyroid gland in which the body’s immune system attacks the thyroid gland, destroying the cells of the thyroid gland

Hormone: A chemical substance that is produced by an endocrine gland and released into the bloodstream to have its effect on other parts of the body. Also known as a “chemical messenger”. For example, thyroid hormone, released by the thyroid gland speeds up or stimulates certain bodily functions.

Hyperthyroidism: Condition in which too much thyroid hormone is circulating throughout the body, causing excessive stimulation of metabolic activity in body cells. Same condition as thyrotoxicosis.

Hypothyroidism: Condition in which too little thyroid hormone is circulating throughout the body, causing inadequate stimulation of metabolic activity in body cells.

Immune system: The body system (consisting primarily of white blood cells) that enables the body to fight infection or reject organs from another individual.

Iodine: A chemical element found naturally in seawater and in many foods that is needed to produce thyroid hormone. Iodized table salt has had iodine added to it.

Lymphoma: Any one of several cancers (including Hodgkin’s disease) that originate in lymph nodes.

Metabolism: The chemical and physical processes in the body that create the substances and generate the energy needed for cells to function, grow normally, and divide. Metabolism is also known as metabolic activity.

Nucleus: The part of the cell that contains genes, the biological form of information that is inherited from one generation to the next and that controls cell activity.

Pituitary gland: A relatively small endocrine gland about the size of a pea. This gland is located underneath the brain and releases a number of essential hormones, including thyroid stimulating hormone (TSH).

Placenta: The structure within the pregnant uterus that is the interface between the maternal and fetal bloodstreams. Oxygen, food substances, and other materials pass from the mother’s bloodstream to the fetus’s bloodstream through the placenta.

Puberty: The last growth phase of childhood, puberty is the period during which a child’s body becomes sexually mature and develops into adult form.

Radioactive iodine: A radioactive form of iodine, which means it emits intense energy due to chemical reactions in the atomic nucleus. It is often used in the treatment of hyperthyroidism in adults and less commonly used in young children.

Synthetic thyroid hormone: Thyroid hormone (T4) that is artificially manufactured but is structurally identical to that naturally produced in the body.

Thyroid gland: Small, butterfly-shaped organ, located in the neck below and in front of the Adam’s apple, which produces thyroid hormone.

Thyroid hormone: Chemical substance produced by the thyroid gland and released into the bloodstream. It interacts with almost all body cells, causing them to increase their metabolic activity. Two forms of thyroid hormone, abbreviated as T3 and T4, are found in blood.

Thyroid-stimulating hormone (TSH): Hormone produced by the pituitary gland that interacts with thyroid cells causing them to produce and release more thyroid hormone into the blood.