Hypopituitarism

For patient information click here

WikiDoc Resources for Hypopituitarism
Articles
Most recent articles on Hypopituitarism Most cited articles on Hypopituitarism Review articles on Hypopituitarism Articles on Hypopituitarism in N Eng J Med, Lancet, BMJ
Media
Powerpoint slides on Hypopituitarism Images of Hypopituitarism Photos of Hypopituitarism Podcasts & MP3s on Hypopituitarism Videos on Hypopituitarism
Evidence Based Medicine
Cochrane Collaboration on Hypopituitarism Bandolier on Hypopituitarism TRIP on Hypopituitarism
Clinical Trials
Ongoing Trials on Hypopituitarism at Clinical Trials.gov Trial results on Hypopituitarism Clinical Trials on Hypopituitarism at Google
Guidelines / Policies / Govt
US National Guidelines Clearinghouse on Hypopituitarism NICE Guidance on Hypopituitarism NHS PRODIGY Guidance FDA on Hypopituitarism CDC on Hypopituitarism
Books
Books on Hypopituitarism
News
Hypopituitarism in the news Be alerted to news on Hypopituitarism News trends on Hypopituitarism
Commentary
Blogs on Hypopituitarism
Definitions
Definitions of Hypopituitarism
Patient Resources / Community
Patient resources on Hypopituitarism Discussion groups on Hypopituitarism Patient Handouts on Hypopituitarism Directions to Hospitals Treating Hypopituitarism Risk calculators and risk factors for Hypopituitarism
Healthcare Provider Resources
Symptoms of Hypopituitarism Causes & Risk Factors for Hypopituitarism Diagnostic studies for Hypopituitarism Treatment of Hypopituitarism
Continuing Medical Education (CME)
CME Programs on Hypopituitarism
International
Hypopituitarism en Espanol Hypopituitarism en Francais
Business
Hypopituitarism in the Marketplace Patents on Hypopituitarism
Experimental / Informatics
List of terms related to Hypopituitarism

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Please Join in Editing This Page and Apply to be an Editor-In-Chief for this topic: There can be one or more than one Editor-In-Chief. You may also apply to be an Associate Editor-In-Chief of one of the subtopics below. Please mail us [2] to indicate your interest in serving either as an Editor-In-Chief of the entire topic or as an Associate Editor-In-Chief for a subtopic. Please be sure to attach your CV and or biographical sketch.

Overview

Hypopituitarism is a medical term describing the deficiency (hypo) of one or more hormones of the pituitary gland. The hypothalamus regulates pituitary secretion by the production of releasing hormones and posterior pituitary hormones and hence its dysfunction can also lead to hypopituitarism.

In endocrinology, deficiency of one or multiple hormones of the anterior pituitary is generally referred to as hypopituitarism, while deficiency of the posterior lobe generally only leads to central diabetes insipidus. The deficiency of all anterior pituitary hormones is termed panhypopituitarism.

Physiology

The hormones of the anterior pituitary include 2 proteins, 3 glycoproteins and a polypeptide:

1. prolactin (PRL) - stimulates milk production in the breast
2. growth hormone (GH) - growth and glucose homeostasis
3. luteinizing hormone (LH) - menstrual cycle and reproduction
4. follicle stimulating hormone (FSH) - same
5. thyroid stimulating hormone (TSH) - stimulates thyroxine production in the thyroid
6. adrenocorticotropic hormone (ACTH) - stimulates glucocorticoid production in the adrenal gland

These hormones are secreted in individually characteristic pulsatile patterns, often with distinct circadian rhythm, rather than at steady rates throughout 24 hours.

The posterior pituitary is the site of release of the nonapeptide hormones antidiuretic hormone (ADH) and oxytocin, the former regulating plasma osmolarity and the latter regulating uterine contractions during childbirth as well milk ejection from the breasts.

Multiple hormone deficiencies

Deficiency of a single pituitary hormone occurs less commonly than deficiency of more than one hormone. Sometimes referred to as progressive pituitary hormone deficiency or partial hypopituitarism, there is usually a predictable order of hormone loss.

Generally, growth hormone is lost first, then luteinizing hormone deficiency follows. The loss of follicle-stimulating hormone, thyroid stimulating hormone, adrenocorticotopic hormones and prolactin typically follow much later. The progressive loss of pituitary hormone secretion is usually a slow process, which can occur over a period of months or years. Hypopituitarism does occasionally start suddenly with rapid onset of symptoms

Most people with hypopituitarism lack growth hormone as well as one or more others. As for the posterior pituitary, antidiuretic hormone deficiency is the main problem, while oxytocin deficiency rarely causes clinically significant problems.

Causes

Hypopituitarism and panhypopituitarism can be congenital or acquired. A partial list of causes and forms:

• Congenital hypopituitarism
  • Hypoplasia of the pituitary
    • Isolated idiopathic congenital hypopituitarism
    • Associated with other congenital syndromes and birth defects
      • Septo-optic dysplasia
      • Holoprosencephaly
      • Chromosome 22 deletion syndrome
      • Rapaport syndrome
  • Single gene defect forms of anterior pituitary hormone deficiency
• Acquired hypopituitarism (Simmonds' disease)
  • trauma (e.g., skull base fracture)
  • surgery (e.g., removal of pituitary neoplasm)
  • tumor - secretory and non-secretory (20%) pituitary or hypothalamic neoplasms, cause hypopituitarism by compressing the remaining tissue
  • inflammation (e.g. sarcoidosis or autoimmune hypophysitis)
  • radiation (e.g., after cranial irradiation for childhood leukemia)
  • shock
    • (Sheehan's syndrome is hypopituitarism after heavy bleeding in childbirth)
  • hemochromatosis
• other diseases.

Diagnosis

Hypopituitarism may come to medical attention by symptoms or features of pituitary hormone deficiency (e.g., poor growth, hypoglycemia, micropenis, delayed puberty, polyuria, impaired libido, fatigue, and many others), or because the physician has diagnosed one of the many disorders and conditions associated with hypopituitarism listed above and tests for it. A provocative test (triple bolus test) measures the secretory response of the pituitary to a stimulus (other hormones, drugs, exercise, etc.) by measuring serum levels of the hormone involved.

Complete differential diagnosis for hypopituitarism

• Anorexia Nervosa
• Bulimia Nervosa
• Changes in body weight
• Congestive Heart Failure
• Emotional disorders
• Empty Sella Syndrome
• Habitual exercise
• Head Trauma
• Hemochromatosis
• Infection

• Fungal
• Malaria
• Meningitis
• Syphillis
• Tuberculosis

• Ischemic nerosis of the pituitary

• Anticoagulant therapy
• Arteriosclerosis
• Arteritis temporalis
• Blood dyscrasias
• Brain Trauma
• Diabetes Mellitus
• Eclampsia
• Increased cranial pressure
• Sheehan's Syndrome
• Sickle Cell Anemia
• Tumor

• Latrogenic
• Parasellar tumor/pituitary compression

• Craniopharyngioma
• Chromophobe adenoma
• Intracranial cartoid branch aneurysm
• Lymphoma
• Meningioma
• Metasteses
• Optic nerve neurinoma

• Pituitary adenomas
• Renal Failure
• Sarcoidosis
• Wegener's Granulomatosis

Replacement therapy

Hypopituitarism and panhypopituitarism are treated by replacement of appropriate hormones. Since most of the anterior pituitary hormones are proteins or glycoproteins released in pulsatile patterns, whose functions are to induce secretion of smaller molecule hormones (thyroid hormones and steroids), it is simpler and less expensive for most purposes to simply replace the target gland hormones. There are a few exceptions, such as fertility induction.

• GH is replaced with growth hormone.
• TSH is replaced with thyroxine.
• ACTH is usually replaced with hydrocortisone but any glucocorticoid may be used.
• LH and FSH are most often replaced by supplying the appropriate sex steroids (e.g., testosterone or estrogen and progestin). Virtually all people who need T or E2 replacement for hypopituitarism rarely have spontaneous, effective spermatogenesis or follicular maturation. Both GnRH by subcutaneous pump and gonadotropins (Pergonal) by daily subcutaneous injections have been used effectively to induce fertility.
• Prolactin is not usually replaced, as infant formula is readily available, simpler, and much cheaper.
• ADH is replaced most commonly with oral, nasal, and sometimes intravenous or subcutaneous desmopressin.
• Oxytocin is most important during labor and delivery at the end of pregnancy, and can be replaced in that circumstance by pitressin.

See also

• growth hormone deficiency
• pituitary gland
• Kallmann syndrome
• Empty sella syndrome
• Insulin tolerance test

External links

• All about Hypopituitarism

Template:WikiDoc Sources