HYPERSECRETION OF ANTERIOR PITUITARY HORMONES Flashcards
Outline some features of hyperpituitarism.
usually due to pituitary tumours (also ectopic)
Often associated with visual field defects.
Endocrine related signs and symptoms.
What can happen as a result of a pituitary tumour compressing the optic chiasm?
bitemporal hemianopia.

What is bitemporal hemianopia?
Loss of preipheral vision
What diseases are caused by excess ACTH, TSH, LH/FSH, Prolactin and GH?
ACTH - cushing’s
TSH - thyrotoxicosis.
LH/FSH - precocious puberty in children
Prolactin - hyperprolactinaemia.
GH - gigantism (child), acromegaly (adult)
Give 3 causes of hyperprolactinaemia.
Physiological - pregnancy, breastfeeding.
Pathological - prolactinoma (often small) - most common pituitary tumour.
What additional problem is presented by high prolactin.
suppression of GnRH pulsatility.
GIve symptoms and signs of hyperprolactinaemia due to pituitary adenoma in men and women.
Women - galactorrhoea (milk production), secondary amenorrhoea, loss of libido, infertility.
Men - galactorrhoea, loss of libido, erectile dysfunction, infertility.
What secretes prolactin?
anterior pituitary lactotroph.
How can release of prolactin be inhibited?
Binding of dopamine from hypothalamic dopaminergic neurones to D2 receptors (hence D2 agonists can be used to inhibit prolactin).
What is the first line of hyperprolactinaemia treatment? How is it administered? Examples.
Dopamine receptor (D2) agonists.
- reducde prolactin secretion.
- reduce tumour size.
Oral administration.
e.g. bromocriptine, cabergoline.
Give some side effects of dopamine receptor agonists.
Nausea and vomiting
Postural hypotension
Dyskinesias
Depression
Why is acromegaly difficult to diagnose.
In men, symptoms progress slowly (in women periods go awry).
What are the results of excess GH?
Increased morbidity and mortality.
What are the most common causes of death in agromegaly patients?
CVD - 60%
respiratory complications - 25%
Cancer - 15%
What grows in acromegaly?
- periosteal bone
- cartilage
- fibrous tissue
- connective tissue
- internal organs (cardiomegaly, splenomegaly, hepatomegaly, etc.)
List the clinical features of acromegaly (7).
- Excessive sweating.
- Headache
- enlarged tongue
- barrel chest
- carpal tunnel syndrome.
- lower jaw protrusion (mandible growth).
- enlargement of supraorbital ridges, nose, hands and feet, thickening of lips and general coarseness of features
Outline the metabolic effects of acromegaly relating to insulin.
excess growth hormone –> increased endogenous glucose production, decreased muscle glucose uptake –> increased insulin production = increased insulin resistance –> impaired glucose tolerance –> diabetes mellitus.
List and explain some complications of acromegaly.
Obstructive sleep apnoea
Hypertension
- directly as a result of GH or due to GH mediated renal Na+ reabsorption.
Cardiomyopathy
-hypertension, direct toxic effects of excess GH on myocardium.
Increased cancer risk
- colonic polyps, regular screening with colonoscopy.
Why is hypogonadism associated with acromegaly?
Prolactin often high in acromegaly - e.g. due to tumour secreting GH and prolactin..
Give 2 ways acromegaly can br diagnosed.
Elevated serum IGF-1.
Failed suppression of GH following oral glucose load.
Outline change in GH during oral glucose tolerance test in someone with acromegaly relative to a normal person.
Paradoxical increase (decrease in normal)

List 4 potential treatments of acromegaly.
Surgery
Somatostatin analogues e.g. octreotide
Dopamine agonists e.g. cabergoline
Radiotherapy.
Name some common side effects from somatostatin analogues.
Nausea, diarrhoea, gallstones.
What are the uses of somatostatin analogues?
Reduce GH secretion and tumour size
pre-treatment before surgery makes reduction easier.
Used post-operatively if not cured while waiting for radiotherapy to take effect.