Which hormones does the anterior pituitary release?
FSH/LH, Prolactin, GH, TSH, ACTH
Where would a disorder in the endocrine gland, the anterior pituitary, hypothalamus result in?
3ry isn't clinically referenced but due to hypothalamic neurones not working
What is hypopituitarism and how does it come about?
Decreased production of all anterior pituitary hormones (a.k.a panhypopituitarism) or of specific hormones -> acquired or congenital (rare)
What is congenital panhypopituitarism - cause, symptoms, MRI?
Rare, due to mutations of TF genes needed for normal pituitary development (PROP1); deficient in GH and >1 pit hormone -> short stature (w/other features); hypoplastic anterior pit gland on MRI (underdeveloped)
What causes acquired panhypopituitarism?
Tumours, radiation, infection, traumatic brain injury, infiltrative disease (often involving pit stalk), inflammatory (hypophysitis), pituitary apoplexy (haemorrhage), peri-partum infarction (Sheehan's syndrome)
Which kind of tumours cause acquired panhypopituitarism?
Hypothalamic (craniopharyngiomas), pituitary (adenomas, metastases, cysts)
Radiation to what causes acquired panhypopituitarism?
Hypothalamic/pituitary damage - GH most vulnerable, TSH relatively resistant
How is panhypopituitarism presented?
2ry means there is nothing wrong with the endocrine gland but with the pituitary so there is nothing to tell the gland to work/function
What is Sheehan's syndrome?
Post-partum hypopituitarism secondary to hypotension (PP-haemorrhage) -> less common in developed countries
What is the cause of Sheehan's syndrome?
Anterior pituitary enlarges in pregnancy (lactotroph hyperplasia) as prolactin increases to prepare to feed the child -> PPH leads to (mainly anterior) pituitary infarction as post-Partum haemorrhage leading to poor perfusion of pit, hence infarction
What are the presentations of Sheehan's syndrome?
Lethargy, anorexia, weight loss -> TSH/ACTH/(GH) deficiency; failure of lactation (Prolactin deficiency); failure to resume menses post delivery; post. pit. usually not affected
What is pituitary apoplexy?
Intra-pituitary haemorrhage or (rarer) infarction -> dramatic presentation in patients with pre-existing pit. adenomas (may be first presentation) -> can be precipitated by anticoagulants
What are the symptoms of pituitary apoplexy?
SEVERE sudden onset headache, visual field defect (compressed optic chiasm; "bitemporal hemianopia"), cavernous sinus involvement may lead to diplopia, ptosis
Which compressed cranial nerves lead to diplopia?
Which compressed cranial nerves lead to ptosis?
How are the CN arranged in relation to the pituitary?
How do you diagnose biochemically hypopituitarism?
Basal plasma conc of pit/target endocrine gland hormones or stimulated "dynamic" pit function tests
What are the problems associated with diagnosing hypopituitarism using basal plasma conc?
Interpretation may be limited, undetectable cortisol, T4 with circulating 1/2 life 6 days, LH/FSH cyclical, GH/ACTH pulsatile
What are the problems associated with diagnosing hypopituitarism using stimulated pit. function tests?
ACTH/GH = stress hormones, in the lab hypoglycaemia (2.2mM) can represent a stressor -> which if insulin-induced stimulates GH and ACTH release - measuring cortisol and GH (rises if normal);TRH (injected) stimulates TSH and GnRH (injected) stimulates FSH/LH released -> if patient has increased levels of all hormones then normal, but if levels stay low or below a threshold then there could be problems
How would you diagnose hypopituitarism using radiology?
Pit. MRI, which may reveal specific pathology (haemorrhage, apoplexy, adenoma) or empty sella turcica meaning there's a thin rim of tissue
What would you use in hormone replacement therapy for ACTH and what would you check?
Hydrocortisone, checking serum cortisol levels
What would you use in hormone replacement therapy for TSH and what would you check?
Thyroxine and check Serum free T4
What would you use in hormone replacement therapy for Women LH/FSH and what would you check?
HRT (E2 plus progestagen) checking symptom improvement and withdrawal bleeds
What would you use in hormone replacement therapy for men LH/FSH and what would you check?
Testosterone checking for symptom improvement and serum testosterone
What would you use in hormone replacement therapy for GH and what would you check?
GH checking IGF1 and growth chart
What is the effect of somatotrophin deficiency?
Children: short stature (<2SDs mean height for child same age and sex). Adults: effects less clear
What are the causes of short stature?
What is the effect of short stature in children on the growth axis?
What is achondroplasia?
Mutation in fibroblast GF receptor 3 (FGF3), with abnormality in growth plate chondrocytes -> impaired linear growth so average size trunk but short arms and legs
What are the different types of dwarfism?
Achondroplasia, pit. dwarfism, laron dwarfism