Non-fucntioning Tumours And Pituitary Hormone Testing 12.12.23 Flashcards
What are the type of pituitary mass lesions whic can be found in pituitary?
Non-functioning pituitary adenomas
Endocrine active pituitary adenomas
Malignant pituitary tumours: functional and non-functional pituitary carcinomas
Metastases in the pituitary (breast, lung, stomach, kidney)
Pituitary cysts: Rathke’s cleft cyst
Where do craniopharyngioma arise from?
Arises from squamous epithelial remnants of Rathke’s pouch (base of brain near pituitary)
What is Rathke’s pouch?
An evagination at the roof of the developing mouth in front of the buccopharyngeal membrane - gives rise to the anterior pituitary
What does Rathke’s pouch give rise to?
Anterior pituitary
What are the two types of craniopharyngioma?
Adamantinous - cyst formation and calcification
Squamous papillary - well circumscribed
What is the Rathke’s cyst?
Single layer of epithelial cells with mucous, cellular or serous compounds in cysts fluid —> it is derived from remnants of Rathke’s pouch
What is a meningioma? What is it a complication of?
Tumour of the meninges, complication of radiotherapy
What is the usual presentation of meningioma
Usually present with loss of visual acuity, endocrine dysfunction and visual field defects
What % of non-functioning pituitary adenomas account for primary intracranial tumours?
10-15%
What are three signs of aggressiveness in non-functioning pituitary adenomas
Large size
Cavernous sinus invasion
Lobulated suprasellar margins
What is the test for non-functioning tumours?
No specific test but absence of hormone secretion, test normal pituitary function
How do you test pituitary function? Which hormones do you test?
Test many hormones: GH, LH/FSH, ACTH, TSH and ADH
Cardiac rhythms and pulsatile
If the peripheral target organ is working normally, the pituitary is working
Deficiency of GH causes what?
Short stature
Abnormal body composition
Reduced muscle mass
Poor quality of life
Deficiency of FSH/LH causes what?
Hypogonadism
Reduced sperm count
Infertility
Menstruation problems
Deficiency of TSH causes what?
Hypothyroidism
Deficiency of ACTH causes what?
Adrenal failure
Decreased pigment
Deficiency of ADH causes what?
Diabetes insipidus
What result would you get for primary hypothyroidism? Where is there a problem with anatomically
Raised TSH and low Ft4 - problem is with the thyroid rather than anterior pituitary gland as TSH is being produced but Ft4 isn’t
What result would you get for hypopituitary in PTA axis? Where is there a problem with anatomically?
Low or normal TSH with low Ft4 - problem with anterior pituitary gland because the cause of the low Ft4 is due to the low TSH from the pituitary gland
What result would you get for Graves’ disease/hyperthyroidism? Where is there a problem with anatomically?
Suppressed TSH and high FT4 - problem with thyroid gland as there is excess Ft4 production therefore suppressed TSH production
What result would you get for TSHoma (very rare)? Where is there a problem with anatomically
High Ft4 with normal or high TSH - there is a functioning tumour of pituitary gland therefore high Ft4
What result would you get for Thyroid hormone resistance? Where is there a problem with anatomically
High Ft4 with normal or high TSH - Ft4 is being produced but it doesn’t work in the body, the body then senses this and produces more TSH
What result would you get for primary hypogonadism in men? Where is there a problem with anatomically
Low testosterone with raised LH/FSH - testes aren’t producing testosterone due to radiotherapy, pituitary gland is working fine as LH and FSH are fine
What result would you get for hypopituitary in HGA axis in men? Where is there a problem with anatomically
Low testosterone with normal or low LH/FSH - pituitary gland is the problem as less testosterone is being produced due to the low LH/FSH
What result would you get for use of anabolic testosterone in men? Where is there a problem with anatomically
Low testosterone and suppressed LH - when someone is injecting testosterone their LH/FSH gets suppressed. If someone suddenly stops injecting testosterone it takes a while for their FSH/LH to start up again therefore for a while they will have low FSH/LH and testosterone and have secondary hypogonadism
How do you measure testosterone levels
Fasted testosterone measured at 0900h and LH/FSH measurement
What are levels of LH/FSH like before puberty?
Oeestradiol very low/undetectable with low LH and FSH although FSH slightly higher than LH
What are levels of LH/FSH like during puberty?
Pulsatile LH increases and oestradiol increases
What are levels of LH/FSH like during post-menarche?
Monthly menstrual cycle with LH/FSH, mid-cycle surge in LH and FSH and levels of oestradiol increase through cycle
What are levels of LH/FSH like during primary ovarian failure (inc. menopause)?
High LH/FSH with FSH greater than LH and l ow oestradiol
What are levels of LH/FSH like during hypopituitary?
Oligo or amenorrhoea with low oestradiol and normal or low LH and FSH
What result would you get for primary adrenal insufficiency? Where is there a problem with anatomically
Low cortisol, high ACTH - poor response to Synacthen, problem with adrenal glands producing cortisol
(Synacthen - give ACTH and stimulate adrenal gland to produce cortisol)
What result would you get for hypopituitarism HPA axis? Where is there a problem with anatomically
Low cortisol, low or normal ACTH, poor response to Synacthen - low cortisol due to problem with pituitary
(Synacthen - give ACTH and stimulate adrenal gland to produce cortisol)
How do you measure GH/IGF1 axis?
IGF-1 and GH stimulation test - insulin stress test, glucagon test
When is growth hormone level greatest? How is GH secreted
Night, secreted in pulses
What are 4 reasons prolactin may be raised?
Stress
Drugs: antipsychotics
Stalk pressure
Prolactinoma
