Hypopituitarism in Children

• The pituitary is a small gland located at the base of the brain, roughly in the space between your eyes.
• It is responsible for the regulation and secretion of a number of different hormones both in adults and in children. These are described in detail below.
• Hypopituitarism is a condition in which the pituitary gland does not produce enough of one or more of these hormones.
• This condition may occur because of disease in the pituitary gland or hypothalamus (a part of the brain that controls the pituitary gland).
• When there is low or no production of all the pituitary hormones, the condition is called hypopituitarism. Hypopituitarism can occur at any age.

Picture of the Pituitary Gland

The pituitary gland sends signals to other glands to produce hormones (for example, it makes thyroid stimulating hormone (TSH - which regulates production of thyroid hormone by the thyroid gland). The hormones released by the pituitary and other glands have a significant impact on important bodily functions, such as growth, reproduction, blood pressure, and metabolism (the physical and chemical processes of the body). When levels of one or more of these hormones are not properly balanced, the body's normal functions can be affected.

The pituitary gland produces several hormones.

• Adrenocorticotropic hormone (ACTH) stimulates the two adrenal glands, each placed close to a kidney. ACTH triggers these adrenal glands to release hormones, including adrenaline (epinephrine) and cortisol, which regulate many aspects of metabolism, immune function, and blood pressure.
• Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) are hormones that control sexual development and function in males and females. They are also called gonadotropins and control production of the sex hormones (such as estrogen and testosterone) as well as egg and sperm production.
• Growth hormone (GH) is a hormone that stimulates normal growth of bones and tissues throughout the body.
• Prolactin is a hormone that stimulates milk production and female breast growth for lactation.
• Thyroid-stimulating hormone (TSH) is a hormone that stimulates production and secretion of thyroid hormones from the thyroid gland (a gland in the front and middle of the neck). Thyroid hormone regulates the body's metabolism and is essential for growth and brain development.
• Antidiuretic hormone (ADH) is a hormone that controls water loss by the kidneys.

In hypopituitarism, the level of one or more of these pituitary hormones is insufficient. The lack of hormone results in a loss of function of the gland or organ that it controls.

The most common pituitary hormone deficiency is growth hormone deficiency. In the United States, growth hormone deficiency occurs rarely with a frequency of less than 1 in 3,480 children.

Hypopituitarism may be congenital (a condition present at birth) and caused by:

• Birth trauma
• Genetic (inherited) disorders
• Central nervous system defects
• Defective, underdeveloped, or absent pituitary gland

Hypopituitarism can also be acquired (a condition that develops later in life) and may be caused by:

• Radiation to the head
• Tumors in the brain
• Other disorders, such as tuberculosis or sarcoidosis, which infiltrate the gland, can result in a reduction in function.

Symptoms vary depending on the child's age, underlying cause, and the involved hormone. Signs and symptoms may develop gradually and may not be specific.

Signs and symptoms that may be present in newborn babies include:

• Small genital organs
• Jaundice (a condition characterized by yellowing of the skin)
• Evidence of hypoglycemia (low blood sugar), such as sluggishness, jitteriness, or seizures
• Irritability due to diabetes insipidus (a condition in which excessive amounts of urine are passed)
• In older infants and children, the following signs and symptoms may be present:
  • Short stature and slow growth; may be associated with delayed tooth development and delayed tooth eruption. Children may fall off their growth curve both in height and /or in weight.
  • Mental development delay
  • Increased thirst and urination
  • Fatigue
  • Weight gain out of proportion to growth
  • Absent or delayed puberty
  • Visual and nervous system problems, such as decreased visual acuity, abnormalities in peripheral vision, or headache

Call the doctor or health care practitioner if the child develops symptoms.

Blood tests may be performed to determine which hormone is low or absent.

• Tests for insulin-like growth factor-I (IGF-I) or insulin-like growth factor binding protein-3 (IGFBP-3) may be performed to detect growth hormone deficiency. Additional testing may also be required.
• Morning serum cortisol levels and a 24-hour urinary free cortisol may be measured to screen for CRH (corticotropin-releasing hormone) deficiency or ACTH deficiency. CRH or ACTH stimulation tests may also be performed.
• For hypothyroidism (a condition involving decreased production of thyroid hormone), the doctor performs simple blood tests for free thyroxine (a hormone contained and released from the thyroid gland) and TSH.
• Tests to determine LH or FSH deficiency vary based on the patient's age.
• Tests for prolactin levels in the blood may be performed.
• If urine specific gravity (a test of how dilute or concentrated the urine is) is low and urine volume is high with excessive thirst, testing for diabetes insipidus may be performed. Note diabetes insipidus ("water diabetes") is completely unrelated to diabetes mellitus ("sugar diabetes"), the more common kind of diabetes.

The doctor may obtain an MRI of the brain to assess the structure of the pituitary or to detect a tumor.

Treatment primarily involves hormone replacement therapy.

Drugs used to treat hypopituitarism replace the deficient hormone.

• Somatotropin (recombinant human growth hormone) is used to treat growth hormone deficiency. This therapy is used to treat growth failure and metabolic abnormalities related to growth hormone deficiency. The treatment (growth) response in infants and children with severe growth hormone deficiency as a result of hypopituitarism is remarkable.
• Levothyroxine (Synthroid, Levoxyl) is used to treat low levels of thyroid hormone. Thyroid hormone is needed for normal growth, metabolism, and nervous system development.
• Hydrocortisone (Cortef, Solu-Cortef) and fludrocortisone (Florinef) are used to treat adrenal insufficiency resulting from ACTH deficiency or primary disorders of the adrenal gland.
• Vasopressin (Pitressin) or desmopressin (DDAVP) may be used to treat diabetes insipidus (ADH deficiency).

Surgery may be performed if a tumor is present within or near the pituitary gland, depending on the type and location of the tumor, and depending on the symptoms being experienced.

The doctor or health care practitioner may schedule routine checkups every three months to monitor growth and development.

Frequent checkups for children on growth hormone replacement therapy may be scheduled to monitor progress and side effects.

A doctor who specializes in studying hormones (a pediatric endocrinologist) should supervise the treatment of children with hypopituitarism.

With appropriate treatment, the prognosis is very good.