Pituitary Disorder Flashcards
What are the physiological effects of Growth hormone?
Control of growth and metabolism via.
- Direct effect - acts on specific cell receptors
- Indirect effect - insulin-like glucose factor 1 stimulates production of chondrocytes (cartilage formation) resulting in bone growth
What is acromegaly?
Excessive production of growth hormone in adults causing severe respiratory, metabolic and CV complications
What are the signs and symptoms of acromegaly?
- Coarsening of facial features
- Enlarged hands and feet
- Numbness and weakness in hands caused by compressed nerves
- Excessive sweating and oily skin
- Vision disturbances
- General tiredness
- Reduced fertility
What causes acromegaly?
Pituitary adenoma
How would you diagnose acromegaly?
GH conc
How would you treat acromegaly?
- Surgery
- Radiotherapy
- Pharmacological suppression of GH conc using somatostatin analogues, dopamine agonists and pegvistomat
How do somatostatin analogues work?
Slow down the release of GH and in some patients shrink tumours
What are examples of long acting somatostatin analogues?
- Octreotide - injected tid (depot prep every 4 weeks)
- Lanreotide - every 4 weeks
- Pasireotide - every 4 weeks
How do dopamine agonists work?
Inhibit GH secretion - only work in some people
Can be used alone or in combo with somatostatin analogues
What is an example of a dopamine agonist?
Bromocriptine every 6-12 hours
What causes GH hyposecretion?
- Deficiency in GH secretion
- Deficiency in target tissue receptors
How do you treat GH hyposecretion?
Somatropin - synthetic human growth hormone produced by recombinant DNA technology
Daily SC or IM injection
What are the physiological effects of prolactin?
- Milk production
- Proliferation and differentiation of breast tissue during pregnancy
- Effect on immune function
What is hyperprolactinaemia?
Excessive production of prolactin from the pituitary
What causes hyperprolactinaemia?
- Iatrogenic - chlorpromazine, oestrogens and OCP’s
- Prolactinomas - prolactin secreting tumours
How would you diagnose hyperprolactinaemia?
- Increased prolactin levels
- Radiological findings - prolactinomas
What are the signs and symptoms of hyperprolactinaemia?
Women
- amenorrhea
- oligomenorrhea
- galactorrhoea
Men
- decreased sex drive
- decreased sperm production
- gynecomastia
How do you treat hyperprolactinaemia?
- Surgery
- Irradiation
- Pharmacological supression of prolactin concentrations - dopamine agonists
How do dopamine agonists work?
- Inhibit release of prolactin by the pituitary
- Decrease cellular DNA synthesis and tumour growth
What dopamine agonists are used for hyperprolactinaemia?
- Cabergoline (best) - more effective and better tolerated than bromocriptine
Weekly dosing
- Bromocriptine - S/E’s decreased by taking with food
Daily dosing
Treatment continued indefinitely
What are the anterior pituitary hormones?
- GH - targets liver and adipose tissue
- Prolactin - mammary gland
- TSH - thyroid gland
- ACTH - adrenal gland
- LH - ovaries and testes
- FSH - ovaries and testes
What are the posterior pituitary hormones?
1 ADH - increased resorption of water by renal tubules and conserves water by reducing urine output
- Oxytocin - labour and expression of milk
What is diabetes insipidous?
Persistent excretion of excessive quantities of urine
What are the symptoms of diabetes insipidous?
- Polyuria
- Polydipsia
What causes diabetes insipidous?
- Cranial diabetes - not enough ADH produced
- Neohrogenic diabetes - kidneys don’t function well
How do you treat diabetes insipidous?
- Desmopressin - analogue of vasopressin with a longer duration of action
- Vasopressin
- Thiazide diuretics
- NSAIDs
