Endocrinology | Glossary of Terms

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Common Endocrinology Terms and Definitions

The Division of Endocrinology defines the following endocrine-related terms:

A - C

A

ACTH (adrenocorticotropic hormone)
A hormone made in the pituitary gland that tells the adrenal gland to make cortisol and androgens.

ACTH stimulation test
One of the laboratory tests used to diagnose adrenal insufficiency. See Health Library.

Acanthosis nigricans
A gray or black discoloration of the skin, usually seen in the neck, underarms and the groin. It is a sign of insulin resistance.

Adrenal glands
Located above each kidney, these glands make the hormones cortisol, aldosterone and androgens. These hormones help to regulate water balance, blood sugar and blood pressure. They also play a role in male and female changes in puberty.

Addison’s disease
A rare disease where the adrenal glands do not make enough cortisol or aldosterone (adrenal hormones). There are different causes of Addison’s disease, but in many cases the body’s immune system may not recognize the adrenal gland and try to destroy it.

Adrenal insufficiency
A condition where the adrenal glands do not make enough cortisol or aldosterone (adrenal hormones). See Health Library.

Aldosterone
A hormone made in the adrenal gland that helps a person’s body balance nutrients such as sodium and potassium.

Ambiguous genitalia
A birth defect that causes a baby’s genitals to look different from typical genitalia, making it hard to tell the sex of the baby.

Amenorrhea
The lack of menstrual cycles in females. See Health Library. There are two types:

Primary Amenorrhea: lack of first cycle or period after age 16.
Secondary Amenorrhea: missed cycles or periods for longer than six months for girls of any age.

Androgens
Male sex hormones that cause and maintain the male sex changes. The main hormone is testosterone. These hormones are made in the testes and adrenal glands.

Antithyroid medications (Methimazole, Tapazole, and PTU)
This medication is used to treat any condition that causes too much thyroid hormone (Graves disease, thyroiditis). It lowers the amount of thyroid hormone produced by the thyroid gland.

Arm span
A measurement of the distance between the middle fingertips of the left and the right hands when arms are spread out as far as possible. This measurement may be used to help your doctor identify growth disorders.

Arginine Clonidine Growth Hormone Stimulation Test
One of the laboratory tests used to diagnose growth hormone deficiency. See Health Library.

B

Bone age X-ray
An X-ray of the left hand and wrist. This X-ray may be a part of the growth evaluation. The doctor will compare the child’s chronological age (actual age) with his skeleton age (bone maturity). Delays or advancements in skeletal age from the child’s actual age may help identify an endocrine problem. See Health Library.

C

Congenital Adrenal Hyperplasia (CAH)
An inherited disorder of the adrenal glands affecting the ability to make enough of the hormones cortisol and aldosterone, but too much of the hormone androgen. If CAH goes untreated, this condition can lead to death.

Newborn girls with this disorder have a swelling of the clitoris (ambiguous genitalia).
Newborn males may have no obvious changes but may enter into puberty as early as age 2-3 years.
Salt wasting is a lack of aldosterone, causing a child to lose large amounts of salt in his urine.
Non salt wasting is a lack of cortisol with enough aldosterone. See Health Library.

Constitutional delay of growth (late bloomer)
A normal variation of growth. A child will grow at a normal rate but appears smaller than children the same age. The bone age and the start of puberty are usually delayed. A child with constitutional delay of growth tends to have a catch-up growth spurt at puberty, reaching a normal adult height.

Cortisol
A hormone made in the adrenal gland, sometimes called “stress hormone.” Cortisol plays a role in the body’s reaction to stress (injury, illness) by controlling blood pressure and blood sugar.

Cushing disorder
This disorder is caused by problems with the pituitary gland that cause too much ACTH in the body. A person with this condition may have a round swollen face, increased weight, weakened muscles and bruise easily. An increase in blood pressure, blood sugar and cholesterol may also be seen.

D - G

D

Desmopressin (DDAVP)
An oral medication that helps to lessen the amount of urine a person will make. This medicine is often used in patients with diabetes insipidus.

DEXA Scan
A special X-ray that measures the amount of minerals, such as calcium, in your bones. The scan tells your doctor how strong your bones are.

Diabetes Insipidus
This condition is a result of a lack of antidiuretic hormone (ADH). This hormone is made by the pituitary gland and helps the kidneys balance fluid in the body. A person with this condition may have a large amount of urine each day and be very thirsty. If untreated, this condition can lead to dehydration, and problems with growth, weight gain and appetite. See Health Library.

E

Endocrine System
See Health Library.

Endocrinologist
A doctor who specializes in the function of the endocrine system and treatment of endocrine disorders.

Epiphyseal plate (epiphyses)
The growing end of the long bones, sometimes called the growth plate.

Estrogen
A “female” hormone that is one of the hormones responsible for breast development, menstrual cycles (periods) and growth in girls. Estrogen is also produced in small amounts in males.

Estrogen Replacement Therapy
A medicine taken by mouth to replace the female hormone that helps to cause the puberty changes in girls. Medication may be given in an oral or patch form.

F

Familial Short Stature
A normal growth pattern that matches closely to the child’s family members. The bone age usually matches the child’s age. See Health Library.

Fanconi anemia
A rare inherited blood disorder that may lead to bone marrow failure. Children with Fanconi anemia are at higher risk for having birth defects, kidney problems, growth problems and cancer. See Health Library.

Fasting
A period of time when a person should stop eating or drinking for several hours. A doctor might ask a person to begin fasting at midnight the day before a test or procedure. Fasting usually includes avoiding everything taken in by mouth, even chewing gum and hard candy. Ask your doctor if you can take any medicines that are due during your fasting period.

Fellowship
In the endocrine program, this is a three-year training period for a pediatrician to become an endocrinologist.

Florinef
A medication taken by mouth that helps replace the adrenal hormone, aldosterone.

G

Galactorrhea
Leaking of milk from the breast that can occur in both males and females who are not breastfeeding.

Goiter
Enlargement of the thyroid gland, which is in the front of the neck, behind the trachea (wind pipe).

Growth failure
A term that your doctor might use when your child has not grown at a normal speed (growth velocity) for her age.

Growth hormone
A hormone that helps with growth, bone and muscle strength, and sugar and fat metabolism. See Health Library.

Growth Hormone Deficiency (GHD)
This condition is due to the pituitary gland not making enough growth hormone for the body. A child with this deficiency will look younger and smaller than children of the same age.

Growth Hormone Replacement Therapy (Genotropin, Humatrope, Norditropin, Nutropin AQ, Saizen, Tev Tropin)
A daily shot that is given for growth hormone deficiency or growth failure. See Health Library.

Growth velocity
The rate of growth a child experiences over a period of time. Normal growth velocities are based on age.

Gynecomastia
Enlargement of one or both breasts in boys. It can be caused by an estrogen and androgen hormone imbalance, or sometimes from too much fatty tissue in overweight boys.

H - K

H

Hirsutism
Excessive growth of facial and body hair (usually in females).

Hyperinsulinism
Above normal levels of insulin in the blood of a person. It is the most common cause of low blood sugars seen in newborn babies. Hyperinsulinism can also lead to decreased insulin sensitivity, which may lead to high blood sugars. Treatment is aimed at keeping blood sugar levels normal and will be based on the cause of the condition.

Hyperparathyroidism
Overactive parathyroid gland causing too much calcium and low phosphorus levels in the blood. Calcium levels that are too high can cause weakness, dehydration, kidney stones, brittle bones, high blood pressure, seizures or coma. Treatment is based on the cause of the condition.

Hyperprolactinemia
An increase of the hormone prolactin secreted from the pituitary gland. An increased prolactin level can cause breast drainage (galactorrhea), irregular menstrual cycles or enlarged breasts.

Hyperthyroidism
An increase in the production of thyroid hormone from the thyroid gland, which causes trouble sleeping, diarrhea, tiredness, goiter, feeling hot, fast heart rate, weight loss, bulging of the eyes or shakiness. Treatment may include antithyroid medications and management of fast heart rates. In some cases, radioactive iodine or surgery could be necessary. See Health Library.

Hypopituitary
A condition resulting from decreased secretion of pituitary hormones. See Health Library.

Hydrocortisone
A medication that replaces the hormone cortisol. It is taken by patients who have conditions of adrenal insufficiency.

Hypothyroid, congenital
A condition found in one out of every 4,000 newborns. All babies are tested for congenital hypothyroidism within the first week of life. When a baby has this condition, her thyroid gland is not producing enough hormone for the brain and body to grow and develop. See Health Library.

Hypothyroid, acquired
A disorder that does not allow the thyroid gland to make enough thyroid hormone for the brain and body to grow and develop normally. Although the condition is more common in adolescent girls, it can be found in boys and girls of any age. See Health Library.

I

Idiopathic Short Stature
Cases where children fall below the third percentile for height on the standard growth chart. After evaluation by an endocrinologist, no medical conditions that cause growth failure are found. Patients may be candidates for growth hormone therapy.

IGF-1
A hormone that plays an important role in growth. IGF-1 is influenced by growth hormone and nutritional status. The amount of hormone found in the blood is useful in screening for growth hormone deficiency .

IGF-1 deficiency
A condition in which the body does not make enough IGF-1. Often, this condition causes short stature.

Insulin
A hormone made in the pancreas that has many functions. One important function is helping your body control blood sugar levels.

Insulin Resistance
A condition in which the body needs more insulin than normal to control blood sugar. This increases a person’s risk of diabetes and heart disease. This condition is usually associated with obesity.

K

Kallmann’s syndrome
A syndrome in which the body makes low levels of the puberty hormones. People with this syndrome have poor or absent ability to smell. An evaluation by a pediatric endocrinologist is recommended at the time of puberty to assist with medications to promote puberty.

Karyotype
A test that looks at a person’s genetic make-up. The test looks at the number, shape and size of the person’s chromosomes (cell structures that carry DNA or genes). Extra, missing or abnormal chromosomes can explain problems with growth and development.

Klinefelter syndrome
This condition occurs in one out of 500 to 1,000 male births. Boys are born with an extra X chromosome. Boys may present with tall, slim stature and delayed puberty. They may also experience behavior problems and delayed language skills. Testosterone therapy is recommended for boys age 11-12 after evaluation by a pediatric endocrinologist. A Klinefelter syndrome support group can be contacted at Klinefeltersyndrome.org.

L - R

L

Leuprolide Stim Test
A specialized blood test used for diagnosing early or delayed puberty. See Health Library.

Levothyroxine
Generic name for thyroid replacement hormone. Brand names may include Synthroid and Levoxyl.

Luteinizing Hormone (LH)
A puberty hormone that stimulates the body to produce testosterone or estrogen.

Lupron Depot
A medication used to suppress puberty. It is given by an injection or shot. See Health Library.

M

Marfan syndrome
Marfan syndrome is a genetic disorder with an incidence rate of one in 5,000 individuals. It affects the body’s connective tissues, or the tissues in between the main cells of each organ of the body. A person with Marfan syndrome will usually be tall, slender and somewhat loose jointed or limber. The arms, legs, fingers and toes may be disproportionately long when compared to the trunk.

McCune Albright syndrome
A genetic condition affecting bone health, puberty and the thyroid. Characteristics may include early puberty, bone fracture and café au lait spots (irregular brown spots on the skin). A child with these symptoms should be evaluated by an endocrinologist to determine medications required to optimize bone health and monitor pubertal advancement.

Metformin
An oral medication that has been shown to improve the body’s use of insulin. This medication is often used in patients with type 2 diabetes mellitus, polycystic ovary syndrome and obesity. The brand name is Glucophage.

Methimazole
A generic name for Tapazole. Used as an anti-thyroid agent in the treatment of hyperthyroidism.

Mixed Meal Tolerance Test
See Health Library.

N

Noonan syndrome
Occurs in about one in 1,000 to 2,500 live births. The actual genetic abnormality has not been discovered. The adolescent growth spurt is often blunted or delayed, and 60 percent of males have undescended testes. In addition to a delay in growth, sexual development is variable and may also be delayed. See Health Library.

O

Obesity
Too much fat in the body, caused by eating more calories than used. Obesity increases risk of diabetes and heart disease. See Health Library.

Oral Glucose Tolerance Test (OGTT)
See Health Library.

P

Pelvic ultrasound
See Health Library.

Pituitary gland
Located at the bottom of the brain, this pea-sized gland helps to control many endocrine functions. The pituitary gland plays an important role in growth, fluid balance, thyroid function and puberty, among other physical processes.

Premature adrenarche
The early growth of pubic hair before the age of 8 years in girls and the age of 9 years in boys. See Health Library.

Premature thelarche
The early appearance of breast development in females who show no other signs of puberty.

Prolactin
A hormone released by the pituitary gland that controls the milk production in the breast tissue.

PTU (Propylthiouracil)
A medication used to treat hyperthyroidism. This medicine slows or stops the thyroid gland from making too much thyroid hormone.

Puberty
A time during which a child’s reproductive system matures, the body changes and growth increases. See Health Library for female and male.

Puberty, delayed
See Health Library.

Puberty, precocious
See Health Library.

R

Radioactive iodine (RAI)
A medication that is given safely by mouth to stop the thyroid gland from making too much thyroid hormone in a patient with an overactive gland. See Health Library.

Rickets
A disorder that causes softening and weakening of the bone in children who have low levels of vitamin D.

S - Z

S

Septo-optic dysplasia
A rare condition in which there is abnormal development in part of brain that can cause changes in a child’s eyes and problems in the pituitary gland.

Small for gestational age (SGA)
SGA is a term used for newborns that are smaller than the third percentile for height and weight for age. The newborn baby’s age is determined by counting the number of weeks since the mother’s last menstrual period.

Short stature
See Health Library.

Solu-cortef
A medicine given to children with adrenal hyperplasia in times of illness. This medicine is given by a shot when a child is vomiting. Solu-cortef prevents a child from entering a life-threatening condition called shock.

Steroids
Medication, such as cortef or prednisone, that is taken to replace cortisol hormones.

Subcutaneous injection
Some medications are to be given into subcutaneous tissue, which is the fatty layer of tissue just under the skin. They are sometimes called “Sub-Q” injections. See Health Library.

Supprelin
A medication used to stop precocious puberty. It is a device that can be surgically placed underneath the skin.

T

Tanner Stage
Medical term used for stages of puberty ranging on a scale of 1 to 5.

Tapazole
A medication used to treat hyperthyroidism. This medicine slows or stops the thyroid gland from making too much thyroid hormone; also called methimazole.

Testosterone
A “male” hormone that is made by the testes in males and by the ovaries in females. Normal levels of testosterone are important for energy and bone strength.

Testosterone Replacement Therapy
This is a male hormone replacement medicine given either by applying to the skin every day or by a shot every two to four weeks in the muscle. This will help start puberty or maintain the male sex changes of adults.

Thyroid gland
A small butterfly-shaped gland of the endocrine system, in the neck area, that makes thyroid hormone.

Thyroid scan
A nuclear scan used to evaluate the function of thyroid or thyroid nodules.

Thyroid nodule
A lump or swelling felt in the neck in the area of the thyroid gland.

Thyroidectomy
Surgical removal of the thyroid gland.

Thyroid stimulating hormone (TSH)
A hormone made in the brain that tells the thyroid gland to make thyroid hormone. The amount of TSH your brain is making can be checked with a blood test.

Turner syndrome
A genetic condition affecting girls with an incidence of one in 2,500 female births. These girls need screening for possible problems related to the heart, kidneys, growth, pubertal development and developmental delays. See Turner Clinic at Cincinnati Children’s and the support group at Turnersyndrome.org.

Type 1 diabetes mellitus
See Health Library.

Type 2 diabetes mellitus
See Health Library.

V

Vitamin D
A vitamin that helps the body absorb nutrients, such as calcium and phosphorus, that make the bones stronger.

W

Water deprivation test
A test used to check the ability of kidneys to concentrate urine.

Endocrinology | Glossary of Terms

Common Endocrinology Terms and Definitions

The Division of Endocrinology defines the following endocrine-related terms:

A

B

C

D

E

F

G

H

I

K

L

M

N

O

P

R

S

T

V

W

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