Hypogonadotropic hypogonadism

Definition

Hypogonadotropic hypogonadism is absent or decreased function of the male testes or the female ovaries. It is considered a form of secondary hypogonadism, which means the condition is due to a problem with the pituitary or hypothalamus gland.

See also: Hypogonadism

Alternative Names

Gonadotropin deficiency; Secondary hypogonadism; Kallmann syndrome

Causes, incidence, and risk factors

Hypogonadotropic hypogonadism is caused by a lack of the gonadal stimulating pituitary hormones: follicle stimulating hormone (FSH) and luteinizing hormone (LH).

Normally, the hypothalamus in the brain releases gonadotropin-releasing hormone (GnRH), which stimulates the pituitary gland to release other hormones, including FSH and LH. These hormones tell the female ovaries and male testes to secrete hormones that are responsible for normal sexual development in puberty. A disruption in this chain of events causes a deficiency of the sex hormones and prevents normal sexual maturity.

Failure of the hypothalamus is most commonly a result of Kallmann syndrome. Kallmann syndrome is an inherited form of hypogonadotropic hypogonadism that can be associated with a loss of smell.

Symptoms

• Absence of secondary sexual characteristics such as pubic, facial, and underarm hair
• Inability to smell (in some cases)
• Lack of development at puberty (may involve incomplete development or a significant delay in development)
• Underdeveloped testicles
• Short stature (in some cases)

Signs and tests

Tests that may be done include:

• Blood tests to measure various hormone levels
• LH response to GnRH
• MRI of the head

Treatment

Treatment depends on the source of the problem but may involve:

• Injections of testosterone
• Slow-release testosterone skin patch
• Estrogen and progesterone pills
• GnRH injections
• Testosterone gels

Expectations (prognosis)

With the right hormone treatment, the person can begin puberty and fertility may be restored.

Complications

• Delayed puberty
• Infertility
• Low self-esteem due to late start of puberty (emotional support may be helpful)

Calling your health care provider

Call your health care provider if your child does not enter puberty as expected.

Prevention

Prevention depends on the cause. People who have a family history of inherited conditions associated with hypogonadism may benefit from genetic counseling. Preventing serious head injuries reduces the risk of pituitary injury-associated hypogonadotropic hypogonadism.

References

AACE Thyroid Task Force. AACE Hypogonadism Guidelines. Endocr Pract. 2002;8(6):441.

Styne DM, Grumbach. Puberty: Ontogeny, neuroendocrinology, physiology, and disorders. In: Kronenberg HM, Shlomo M, Polonsky KS, Larsen PR, eds. Williams Textbook of Endocrinology. 11th ed. Philadelphia, Pa: Saunders Elsevier;2008:chap 24.