16- Pituitary Disorders

Question 1

• what is the pituitary gland known as?
• how do pituitary tumours present clinically?
• what is hypopituitarism as a result of a pituitary tumour and what are symptoms?

Answer 1

• the pituitary gland is the conductor of the endocrine orchestra.
• visual loss ie visual field loss due to pressure on optic chiasm, headache (due to mass on local structures), hypo or hyper secretion(abnormality in pituitary function)
• reduced pituitary function. Results in growth hormone deficiency, gonadotropin deficiency( causes delayed puberty in kids, loss of sexual characteristics in adults), TSH (cold, weight gain, tired) & ACTH (low cortisol, tired, low Na+) deficiencies (a later feature of pit tumours)

Question 2

• another abnormality of pituitary function as a result of a pit tumour is hormone excess. What hormones does this affect?
• how would you assess for a pit disease biochemically, dynamically and radiologically?
• what is a prolactinoma? how is it treated?

Answer 2

• prolactin, GH and ACTH (common), TSH and LH/FSH (rare)
• biochemical=blood test, dynamic=stimulation test if suspected deficiency (stimulate ACTH or test stress response to hypoglycaemia)or suppression test if suspected excess (suppress ACTH w steroids), radiological=MRI for tumour.
• prolactinoma=a prolactin secreting pituitary tumour, can be large or small, treated w tablets not an operation, tumour will shrink w dopamine agonist bc dopamine inhibits prolactin.

Question 3

• define hyper prolactinaemia. Give symptoms for women and men, give 2 causes of a high prolactin and pit mass.
• how is prolactinoma treated?

Answer 3

-prolactin is in excess and inhibits LH secretion. In women=menstrual disturbance, fertility problems, milky discharge from nipples. In men=present later than women as they have no periods, usually macro adenomas (larger tumours), visual loss.
If prolactin less than 5000 may be bc of disinhibition (stalk effect-blockage of pit stalk), if more than 5000 due to prolactinoma (prolactin secreting tumour).
-dopomine agonists stimulate D2 receptor, make sure patient not pregnant.

Question 4

• define acromegaly, give telltale symptoms and some long term complications of untreated acromegaly.
• what biochemical tests can confirm this disease?
• how do you treat acromegaly?

Answer 4

• a growth hormone secreting pituitary tumour, leads to large extremities (hands + feet), leads to gradual change in features over years, can cause=premature CV death, increased risk of colonic cancers, hypertension and diabetes.
• oral glucose tolerance test w GH response, should lower GH.
• treated=surgical removal of tumour, reduction of GH secretion via dopamine agonist, radiotherapy.

Question 5

• define Cushing’s disease.give some classic signs.
• what is Cushing’s syndrome?
• what is diabetes insipidus?what is it caused by?

Answer 5

• an ACTH secreting pituitary tumour, causes=round pink moon shaped face, skinny arms and legs, red striae/stretch marks, HBP and diabetes, fat around abdomen, thin bones.
• Cushing’s syndrome= may be caused by other pathologies eg adrenal tumour, ectopic ACTH, steroid medication.
• condition characterised by large amounts of dilute urine and increased thirst due to fluid loss. Posterior pit gland secretes ADH, they have a lack of ADH.

Question 6

• give the difference between cranial DI and nephrogenic DI (DI=diabetes insipidus)
• give consequences of untreated DI. Treat?
• what is pituitary apoplexy and how does it present?

Answer 6

• nephrogenic= kidney disease, cranial =pituitary disease, causes can be inflammation, malignancy, infection.
• severe dehydration, very high Na+ levels bc water all leaves causing Na+ to build up. Treat=nasal spray
• pituitary apoplexy=sudden vascular event in a pituitary tumour, bleeding or infarct, presents as sudden onset headache, double vision, needs prompt treatment.