Pituitary Disorders Flashcards
What hormones are released from the anterior pituitary gland?
TSH, ACTH, GH, prolactin, LH/FSH
What hormones are released from the posterior pituitary gland?
Oxytocin and ADH
Which hormones released from the anterior pituitary gland are trophic hormones, and are released from cells known as basophils?
TSH, ACTH and LH/FSH
Which hormones released from the anterior pituitary gland are non-trophic hormones, and are released from cells known as acidophils?
GH and prolactin
What is the most common pituitary tumour?
Pituitary adenoma
What is the definition of a microadenoma and macroadenoma?
Microadenoma = < 1cm, macroadenoma = > 1cm
A non-functioning pituitary adenoma does not produce a hormone in excess but instead may cause what?
Generalised hypopituitarism
Pituitary adenomas may be sporadic or they may be associated with which genetic condition?
MEN1
What is the most common type of pituitary adenoma?
Prolactinoma
What is the second most common type of pituitary adenoma?
Non-functioning
What are the most common symptoms of a pituitary adenoma caused by a local pressure effect?
Headache, bitemporal hemianopia, palsy of cranial nerves III/IV/VI
Which 3 investigations are required for everyone with a suspected pituitary adenoma?
Hormone profile, formal visual field testing, pituitary MRI
When replacing hormones (in cases of panhypopituitarism for example), which hormone should be given first?
Hydrocortisone
Most pituitary surgery is carried out with what approach?
Trans-sphenoidal
What treatment can be used for residual or recurrent pituitary adenomas after surgery?
Radiotherapy
Why may fertility be reduced after surgery to remove a pituitary adenoma?
Decreased gonadotrophins
What is pituitary apoplexy?
Rapid pituitary enlargement from a bleed into a tumour
How is the release of prolactin controlled?
It is under tonic inhibition by hypothalamic dopamine
What are some physiological causes of hyperprolactinaemia?
Pregnancy, breastfeeding, stress
What is the most common cause of hyperprolactinaemia?
Drugs
What are some examples of drugs which may cause hyperprolactinaemia?
Metoclopramide, anti-psychotics, oestrogens, ecstasy/MDMA
What other endocrine abnormality may cause hyperprolactinaemia as a result?
Hypothyroidism
Hyperprolactinaemia tends to present earlier in which gender?
Females
If the lowest GH level during an OGTT is above what value, acromegaly can be diagnosed?
1mcg/L
Both bromocriptine and cabergoline are associated with what severe side effect? How should this be monitored?
Pulmonary/cardiac/retroperitoneal fibrosis - monitor with ECHO
What is the second line treatment for a prolactinoma?
Trans-sphenoidal surgery
When should the GH antagonist pegvisomant be used in the treatment of acromegaly?
In those who are intolerant of a somatostatin analogue
What hormone, released from the hypothalamus, increases secretion of growth hormone from the anterior pituitary gland?
Growth hormone releasing hormone
What hormone, released from the hypothalamus, decreases secretion of growth hormone from the anterior pituitary gland?
Somatostatin
What effect does a high-dose dexamethasone suppression test have on plasma cortisol levels in those with Cushing’s disease?
May more than halve the level
If an increased level of growth hormone occurs before the onset of puberty, what does this cause?
Pituitary gigantism
What are the main complications of acromegaly?
Impaired glucose tolerance/diabetes, vascular disease, cardiomyopathy, increased risk of colonic cancer
A high glucose level usually has what effect on growth hormone?
Decreases GH
If basal serum GH is increased and/or if IGF-1 is increased, what investigation is indicated?
OGTT
What are the potential causes of panhypopituitarism?
Pituitary tumour, surgery or irradiation
What is the first line treatment for acromegaly?
Trans-sphenoidal surgery
If surgery fails to correct GH/IGF-1 levels, what are some second line options that can be tried next?
Somatostatin analogue (octreotide) or radiotherapy
Is Cushing’s disease more likely to be caused by a micro or macroadenoma?
Microadenoma
What effect does a low-dose dexamethasone suppression test have on plasma cortisol levels in those with Cushing’s disease?
No effect
If the source of Cushing’s disease is undetectable, what treatment can be useful?
Bilateral adrenalectomy
Where does a craniopharyngioma arise from?
Rathke’s pouch
What is the commonest childhood intra-cranial tumour?
Craniopharyngioma
How do craniopharyngiomas in childhood present?
Growth failure
In what order are anterior pituitary hormones affected by panhypopituitarism?
GH - LH/FSH - prolactin - TSH - ACTH
When does Sheehan’s syndrome usually present?
After a delivery involving post-partum haemorrhage
What effect does Sheehan’s syndrome have?
Panhypopituitarism
What investigation is used in panhypopituitarism to assess the adrenal axis?
Short Synacthen test
What investigation is used in panhypopituitarism to assess the adrenal and growth hormone axes?
Insulin tolerance test
What imaging investigation is indicated in an individual with panhypopituitarism?
Pituitary MRI
How is panhypopituitarism treated?
Hormone replacement and treatment of the underlying cause
