4 - pituitary Flashcards
what does
a) anterior
b) posterior
pituitary secrete?
a) GH, LH/FSH, ACTH, TSH, prolactin
b) ADH & oxytocin
what makes prolactin unique from the other hormones made in anterior pituitary?
- it’s controlled by inhibition of hypothalamus, hypothalamus makes dopamine which inhibits prolactin secretion
- prolactin is direct target - it’s secreted from anterior pituitary and directly acts on target tissues whereas all the others have intermediate to act on e.g. TSH then on thyroid for T3&4, ACTH acts on adrenal which makes cortisol etc
what are the baseline pituitary function tests? (the ones that should be done as basic to test pituitary function)
- 9am cortisol (IMPORTANT). normal = less than 400
- thyroid profile (TSH, fT3&T4)
- prolactin
- LH/FSH, oestradiol or testosterone
- IGF-1
*basically test a bunch of the functions of pituitary (makes sense)
what test is done to assess pituitary & adrenal function?
synacthen test = give synthetic ACTH
*if chronic pituitary problem then adrenal gland atrophied so won’t respond to ACTH stimulus (by making cortisol). therefore shows function of pituitary & adrenal
note - won’t work if acute pituitary failure as adrenal gland not atrophied yet
what is gold standard test for adrenal insufficiency or hypopituitarism?
insulin stress test - give insulin to make hypoglycaemic, this should stimulate cortisol + growth hormone secretion
what is hypopituitarism? what happens to what hormones?
when pituitary gland not making enough
- low GH = growth failure
- low TSH = secondary hypothyroidism
- low LH/FSH = hypogonadism
- low ACTH = secondary hypoadrenal
also ADH deficiency so arginine vasopressin deficiency (diabetes insipidus)
what is presentation of ACTH deficiency?
chronic = fatigue, pallor, anorexia, weakness
acute = weakness, dizziness, nausea, vomiting, shock
*in kids = delayed puberty, failure to thrive
what is presentation of TSH deficiency?
tiredness, cold intolerance, constipation, hair loss, dry skin, hoarseness, cognitive slowing
*in kids = growth + development impairment
what is presentation of LH/FSH deficiency? in females and males
females = oligomenorrhea, loss of libido, dyspareunia, infertility
males = loss of libido, erectile dysfunction, reduced sexual hair growth
*in kids = delayed puberty
what is presentation of GH deficiency?
decreased muscle mass, visceral obesity, fatigue, decreased quality of life, impairment of attention + memory
*in kids impaired growth
what is result of ADH deficiency?
polyuria + polydipsia (as ADH conserves water + osmolality)
what is management of hypopituitarism if deficient in
a) cortisol
b) T4
c) oestrogen or testosterone
d) GH
e) ADH
a) hydrocortisone - 15-25mg per day
b) thyroxine - 100-150mg per day
c) HRT female or testosterone male
d) GH replacement, high in kids and low or none in adults
e) desmospray or desmopressin tablets
what side effects to watch out for in testosterone replacement?
monitor as polycythaemia and prostate enlargement (not cancer but can make prostate symptoms)
what are the main pituitary tumours (that can cause hypopituitarism)?
non functioning tumour = gonadotroph
functioning = prolactinomas (commonest), acromegaly, cushing’s disease, TSHoma
what size is microadenoma and macroadenoma?
microadenoma= less than 1cm
macroadenoma = more than 1 cm
what pituitary tumour radiological classification?
modified knosp classification
what is presentation of non-functioning tumour gonadotroph?
- symptoms of hypopituitarism so ACTH, TSH, LH/FSH, GH deficiency
- raised prolactin (because tumour inhibit inhibitory signals from dopamine)
- can have headache or visual disturbances if macroadenoma
what is management of gonadotroph tumour?
- if just hormone deficiency but no visual field defect etc then can just replace hormone + observe
- transsphenoidal surgery + replace hormone deficiencies if visual disturbances etc
*if residual growing →further surgery or radiotherapy
what is presentation of prolactinoma?
female = oligomenorrhea, vaginal dryness, depression
male = libido reduction, erectile dysfunction, gynaecomastia
- weight gain
- delayed puberty
- hypogonadism (decreased muscle mass, fatigue, impaired growth)
- galactorrhea
- osteopenia or osteoporosis
what are other causes of high prolactin? why important?
prolactin could be high in loads of things like pregnancy, period, lack of sleep, low mood etc
*this means important to do 2nd test of prolactin if high (might not be prolactinoma). also bear in mind young female with no period and high prolactin could be pregnant not prolactinoma!
what are investigations for prolactinoma diagnosis?
- serum prolactin & baseline pituitary function tests
- MRI pituitary
what is management of prolactinoma?
- chat with patient = they can have either surgery or medication
medication = dopamine agonist e.g. cabergoline (1 or 2 a week)
surgery = mostly if dopamine resistant or women after menopause
what are side effects of dopamine agonists?
dopamine agonist e.g. cabergoline (for prolactinoma)
side effects →fibrosis reactions (but unlikely since low dose), impulse control/psychiatric disturbance (more of a worry, need to counsel someone before about addiction etc)
what is acromegaly?
excess GH secretion from pituitary adenoma (causes gigantism in kids and acromegaly in adults)
what is presentation of acromegaly?
- thickened soft tissue (facial features big, large jaw, large hands & feet)
- obstructive sleep apnoea (thickened nasopharynx)
- arthropathy like vertebral fracture, osteoporosis, carpal tunnel syndrome
- CV morbidity
- headaches
- diabetes
- dyslipidemia
- local pituitary effects like visual fields, hypopituitarism
what is involved in diagnosis of acromegaly?
- check IGF-1 = raised in acromegaly
- oral glucose tolerance test (suppression) = give glucose which should suppress GH if normal
- also MRI imaging
what is management of acromegaly?
surgery = 1st line. if not entirely work then radiotherapy
*can have medication like somatostatin analogues (octreotide, pasireotide) which will shrink tumour while on meds - used until surgery done & for symptoms
what are complications of acromegaly?
- cancer surveillance - associated with colon and tubulo-villlous adenoma
- CV risk
- obstructive sleep apnoea
- arthropathy
what is cushing’s syndrome? causes?
too much cortisol
most common cause = steroids
2nd most common = pituitary driven which is when called cushing’s disease
*can also be adrenal tumour (ACTH independent. adrenal not listening to pituitary) or ectopic ACTH production
what is pseudo-cushing’s?
physiological hypercortisolemia = alcohol or depression etc can cause (basically things that cause high cortisol temporarily)
what is presentation of cushing’s?
excess cortisol = muscle wasting, osteoporosis, thin skin, depression
excess mineralocorticoid = hypertension & oedema
excess androgen = virilism, hirsutism, acne, oligo-amenorrhoea
symptoms = moon face, easy bruising too
what is involved in diagnosis of cushing’s?
- overnight 1 mg dexamethasone suppression test →less than 50 cortisol normal. if high cortisol then positive (dexamethasone should lower cortisol)
- urinary free cortisol = 24 hr urine collection
- diurnal cortisol variation = persistent high cortisol
then after know it’s cushings = find cause by measure ACTH (if low then adrenal since ACTH independent) and if normal or high then pituitary or ectopic
- then MRI
what is surgical treatment of cushing’s? (different depending on cause)
pituitary
1. hypophysectomy (transsphenoidal) →1st line therapy
2. external radiotherapy if need more
3. last resort = bilateral adrenalectomy (immediately stops excess cortisol but bad additional consequences )
adrenal →adrenalectomy
ectopic →remove source or bilateral adrenalectomy
what is medical therapy of cushing’s?
- adrenal steroidogenesis inhibitors = block cortisol synthesise.g. metyrapone, ketoconazole (hepatotoxic)
what is apoplexy? risk factors?
= rare clinical syndrome where rapid expansion of pituitary tumour due to haemorrhage or infarction
(more likely if had surgery, on GnRH analogues, anticoagulation , hypertension, diabetes, high altitude
what is presentation of apoplexy?
- severe headache
- nausea & vomiting
- vision - acuity & visual field defects
- ocular palsy
- hypopituitarism
- reduced GCS
*rapid expansion of pituitary tumour due to haemorrhage or infarction
what is management of apoplexy?
- surgery and hormone replacement
*diagnose with visual field assessment & MRI & pituitary function tests
what is hypophysitis?
= inflammation of pituitary gland
by a bunch of things like autoimmune stuff, medication, infection (TB), paraneoplastic etc
what is symptoms, diagnosis and management of hypophysitis? (pretty basic)
*hypophysitis = inflammation of pituitary
clinical
- headache
- symptoms of hypopituitarism
diagnosis
- MRI
- pituitary function
- biopsy
management
- treat underlying cause (often steroid)
- hormone deficit replacement
what is arginine vasopressin deficiency?
= used to be called diabetes insipidus. caused by idiopathic, trauma or tumour
*when ADH deficient so poor water conservation and osmolality control
how to diagnose arginine vasopressin deficiency?
water deprivation test = don’t drink. progressively concentrate urine to conserve water. diabetes insipidus peoples continue passing dilute urine and osmolality serum increase
what is treatment of arginine vasopressin deficiency?
- desmospray
- desmopressin tablet
