Week 4: hypopituitarism

Question 1

pituitary diseases that can cause hypopituitarism

Answer 1

• macroadenomas
• pituitary surgery
• pituitary radiation
• pituitary apoplexy: sudden hemorrhage, usually into underlying pituitary macro adenomas.
• pituitary infarction (sheehan’s syndrome): post partum infarct due to excessive blood loss and increased need of a hyperplastic pituitary from increased prolactin formation
• genetic deficiencies (isolated or multiple)
• inflammatory disorders (histiocytosis, lymphocytic hypophysitis)
• severe trauma
• infections (TB, fungal): rare
• vascular: subarachnoid hemorrhage, carotid aneurysm,

Question 2

Order of loss of pituitary hormones due to non-functioning adenomas

Answer 2

1. GH
2. LH/FSH
3. ACTH
4. TSH
   - TSH can be detected as normal even with low T4 because of formation of abnormal isoforms of TSH that are inactive and detected by the test

Question 3

Clinical features of hypopituitarism

Answer 3

• GH: fatigue, decreased muscle strength
• LH/FSH: sexual dysfunction, infertility, fatigue, anemia, decrease in secondary sex characteristics
• ACTH: weakness, weight loss, hypotension. No hyperkalemia in secondary adrenal insufficiency b/c RAAS system is independently regulated
• TSH: fatigue, cold intolerance, weakness, anemia
• prolactin: inability to lactate

Question 4

Laboratory evaluation of hypopituitarism

Answer 4

• testosterone or estradiol
• LH
• serum cortisol (lacks diurnal variation)
• prolactin
• GH/IGF (but not diagnostic), assume is decreased if all other hormones are decreased
• TSH, T4: TSH is usually normal

Question 5

Treatment of hypopituitarism

Answer 5

• gonadal steroids: if fertility not an issue, women treated with estrogen/progestins and men with testosterone. Otherwise treat with gonadotropins or GnRH if hypothalamic issue
• GH: recombinant human growth hormone. Benefits include decreasing fat mass, increasing bone density, increasing strength and emotional health
• glucocorticoids
• L-T4