Pituitary Disorders Flashcards
how common are pituitary disorders ? and most common cause is?
rare
- 70,000 patients in the UK
- most common cause of pituitary malfunction
what’re most pituitary tumours like? and what do they result in?
- non-functioning as in the don’t produce hormones
- this results in inadequate production of 1 or more hormone due to the tumour putting pressure on the glandular tissue as it grows. so you get consequnce associated with the depleted hormone
- aso due to the swelling it puts pressure on surrounding tissue swell c headaches and visual problems d compression of the optic nerve bi-temporal semi-anopia
investigations of someone with a suspected pituitary tumour
I) delineation of the size, anatomy, topographical location of the pituitary / parapituitary mass (using MRI)
ii) assess visual field
iii) assess endocrine function (measure hormone levels in the blood or by staining sections from.a biopsy of the tumour with antibodies of the relevant hormone e.g. ACTH receptor to see if ACTH is made or not
hypopituitarism
- insufficient hormone produciton is mostly d adenoma(bening tumout from glandular tissue) of pituitary (rare c = radiation therapy, inflammation disease and head injury)
- usually progressive loss of AP, first hormones to suffer is FSH/LH and GH
- migh then present iwth panhypopituitarism.
- secretionof ADh adn oxytoxin is affected if the tumour affects the hypothalamic function or if inflammation is involved with the tumour
panhypopituitarism
-deficency of all hormones
when are the hormones of post.pit. affected and what hormones are affected
- oxytocin and ADH, only when hypothalamic function affected or inflammatory process
GH deficiency symptoms adults
- adults ; decreased exercise tolerance, muscle strength and ^ body fat and reduced sense of well being.
- usually due to mass d pituitary adenoma {(hypopituitarism) but sometime GHR receptor gene mutation or inflammatory response
GH defieiceny in kids and is there a treatment
- 1/3800briths
- little affect on fetual growth but prenatal deficiency can c hypoglycaemia and jaundice
- post birth from 1 year till teens they have poor stature and growth
- human recominant DNA techonology is used in the treatmetn case
Gonadotropin deficency aka? and what is it?
- hypogonadism
- d pit. adenoma
- c lack of libido, infertility, oligomenorrhoea (infrequent periods) or amenorrhea (no periods) of women in reproductive age
- in men can cause v libido and impotence
ADH deficiency
- d hypothalamic tumour(Since synthesised there) or d radiotherapy, autoimmune infiltration of meningitis (inflammatory process)
- c excess urine and dehydration and polydipsia (increased thirst)
- presents as diabetes insipidus; very dilute urine resulting in dehydration and increased sensation of thirst polydipsia
diabetes insipidus
- ADH deficicey
- since ADh promotes water reabsorption you odnt absorb water and instead pee alot more water out, this results in more dilute urine andpolydipsia (more thirsty)
Hyperpituituarism 3 important conditions
- prolactin excess,
- GH excess
- ACTH excess
Prolactin excess
- usually c lactropes in AP to secrete prolactin d PRH and inhibit it by dopamine
- too much prolactin in the blood due to the high levels of dopamine, so ou end up with hyperprolactinaemia (^ prolactin in the blood). symptoms as a result xs prolactin;
- galactorrhoea (unexplained milk production rare in men)
- gynecomastia ( hard breast tissue)
- hypogonadsim (diminished activity of testes ovaries)
- amonerhhea (no period)
- erectile dysfunction
how does hyperprolactaemia cause hypogonadism
the high levels of dopamine in the hypothalamus (due to th enegative feedback of the high prolactin levels in the blood) inhibit GnRH secretion from the hypothalmus and therefore no FSH, LH, secretion from ant.pit
c of hyperprolactinaemia
- usually AP adenoma c XS prolactin known as prolactinoma (benign d to -oma)
- but also stress, antipsychotics (haloperidol) and antidepressants (clomipramine ), pregnancy, exercise
treatment d domaine c prolactin^
-carbergoline a dopamine receptor agonist but rarely
or trans-sphenoidal surgery or radiotherapy
GH ex
- adenoma of AP larger than 10mm in diameter
this is causes by excress GH secretion and stimlation of IGF-1 production, wc inturn causes GH and IGF-1 receptors to be activated
but this takes years to manifest and so take foeverto diagnose (6yrs)
signs = changes in phsyical appearance, broad nose, coarse facial features, acromegaly, excessive sweating, deepenign voice due ot the hypertrophy of the soft tissues in the upper airay
GH excesss in kids
- before fusion of the epiphyseal plates c gigantism, where you grow really tall forever
- since GH antagonises insulin there’s metabolic issues and ^ IGF1 are associated with diabetes and some cancers
treatments for acromegaly
- surgery to remove ademoma /radio/drug therapy
2) dopamine receptor inhibitor to decrease GH levels (but higher levels needed if prolactin secreting pit adenoma present
3) somatostatin (limits GH secretion)
4) GH receptor antaongists like Pegvisomant
excess ACTH is a cause of what condition
-Cushing’s syndrome
how does GH work compared to insulin
antagonises it
pituitary apoplexy
-stroke
