What is Hypopituitarism

Hypopituitarism is a disease of the Pituitary Gland. It does not generally manifest until more than 75% of the gland is destroyed.

Statistics on Hypopituitarism

Unknown

Risk Factors for Hypopituitarism

 

  • Any pituitary disease interfering with the synthesis or secretion of anterior pituitary hormones (responsible for 90% of cases).
  • Hypothalamic and pituitary stalk disorders can also cause this condition.
    These include: pituitary tumour, pituitary apoplexy or infarction, transsphendidal surgery, empty sella syndrome, lumphocytic hypophysitis, haemochromatosis, granulomatous diseases, hypothalamic tumour, metastases, sellar and suprasellar cysts, irradiation, head trauma, congenital defects.

 

Progression of Hypopituitarism

The natural history depends on the underlying disease process. Anterior pituitary hormonal deficiencies may reverse or improve in patients who are successfully treated for their underlying disorder (e.g. pituitary surgery, glucocorticoid treatment of sarcoidosis).

In many cases the deficiencies are permanent. Mortality depends on the underlying illness. An increase in the icnidence of cardiovascular events has been reported.

How is Hypopituitarism Diagnosed?

 

  • Urea and electrolytes: mild hyponatraemia is common in patients with central adrenocortical insufficiency. Potassium is usually normal. There is hypernatraemia and decreased urine specific gravity in patients with diabetes insipidus.
  • Full blood count – normocytic normochromic anaemia is common and may be due to deficiencies in cortisol, thyroid or sex steroid hormones.
  • Lipids – often hypercholesterolaemia with hypothyroidism
  • Liver function tests – often elevated transaminases and ALP with hypothyroidism.
  • Blood glucose – low with growth hormone deficiency and adrenocortical insufficiency.

    Prognosis of Hypopituitarism

    Hypopituitarism is usually permanent and requires life-long treatment; however, a normal life span can be expected

    How is Hypopituitarism Treated?

    Treatment involves treating the underlying disorder, hormonal replacement therapy and patient education.

     

  • Adrenocorticotrophic hormone (ACTH) deficiency: Hydrocortisone (e.g. 20mg orally am and 10mg pm) or Prednisolone (5mg orally am and 2.5mg pm). Alleiving symptoms and 24 hour urine cortisol used to monitor treatment.
  • Hypothyroidism: Thyroxine (average daily dose is 75-150mcg)
  • Hypogonadism: In men – testosterone (eg 200mg IM on 1st and 15th day of each month).
  • In women – conjugated oestrogens on days 1-25 of each month (0.625-1.25mg).
  • Medroxyprogesterone (5-10mg) should be given on days 15-25 for all women with a uterus.
  • Growth hormone replacement: efficacy in adults not yet established. Indicated in children with short stature.
  • Vasopressin deficiency: treatment indicated if symptoms disrupt the patient’s daily activities, daily urine volume greater than 4-6L or evidence of dehydration. This is with synthetic vasopressin, DDAVP (5-10mcg intranasal at night, some requiring 20-30mcg over the day).

    Hypopituitarism References

    [1] Braunwald, Fauci, Kasper, Hauser, Longo, Jameson. Harrison’s Principles of Internal Medicine. 15th Edition. McGraw-Hill. 2001
    [2] Cotran, Kumar, Collins 6th edition. Robbins Pathologic Basis of Disease. WB Saunders Company. 1999.
    [3] Hurst JW (Editor-in-chief). Medicine for the practicing physician. 4th edition Appleton and Lange 1996.
    [4] Kumar P, Clark M. CLINICAL MEDICINE. WB Saunders 2002 Pg 427-430.
    [5] Longore M, Wilkinson I, Torok E. OXFORD HANDBOOK OF CLINICAL MEDICINE. Oxford Universtiy Press. 2001