Pituitary Disorders Flashcards
What is seen in GH def?
In childhood = pit dwarfism, delayed/no sexual devel in teens – will respond to GH therapy
Outline the characteristics of GH excess
Gigantism, acromegaly
What is the clinical presentation of pituitary tumours?
Visual loss (optic chiasm is found superior, compression), headache
What happens when there is loss of control of the pituitary by the hypothalamus?
Rise in –ve control hormones,
decrease in +ve control hormones
What is the first sign in women that they have a pituitary problem?
Change in their periods
Outline the endocrine blood tests use to asses pituitary function
Thyroid axis: fT4, TSH.
Gonadal axis: LH, FSH, testosterone, oestradiol.
Prolactin axis: serum prolactin.
HPA axis: cortisol (morning).
GH axis: GH, IGF-1
What dynamic tests are used to assess pituitary function?
Stim test = for suspected def.
Suppression test = suspected excess
What imaging techniques are used to assess pituitary disease?
MRI
What is a prolactinoma?
Prolactin-secretin pit tumour, larger the tumour the higher the prolactin, treated with tablets = dopamine inhibits prolactin
What are the long-term complications of untreated acromegaly?
Premature cardiovascular death,
increased risk of colonic tumours/thyroid cancer,
disfigured body changes that may be irreversible,
hypertension,
DM
What are the biochemical tests to confirm acromegaly?
Oral glucose tolerance test (OGTT) measuring GH response.
GH day curve (GHDC) observing elevated mean GH
Outline the treatment for acromegaly
Surgical removal of tumour.
Reduce GH secretion = dopamine agonist, somatostatin analogues.
Block the GH receptor.
Radiotherapy
What is cushings disease?
ACTH-secreting pit tumour, red striae, buffalo hump
What is cushings syndrome?
Pathologies other than a tumour
What is diabetes insipidus?
Vasopressin def = water not reabsorbed large quantities of pale (insipid) urine = extreme thirst
How does ADH work?
Opens aquaporins to reabsorb water – lowers urinating
What are the consequences of untreated DI?
Severe dehydration, hypernatraemia, reduced consciousness, coma, death
What is pituitary apoplexy?
Sudden vascular event in pit tumour = haemorrhage/infarction – presents: sudden headache, double vision, cranial nerve palsy
What is the name of the surgical procedure to remove a pituitary tumor though the nose?
Transsphenoidal surgery
What is the diff between gigantism and acromegaly?
gigantism = high GH, in childhood before epiphyseal plate closure
acromegaly = high GH, in adults after epiphyseal plate closure
What is a symptom of hyperprolactinaemia?
Galactorrhoea = milky secretion from the breasts
What is a clinical consequence of untreated DI?
Hypernatraemia
What is the normal pattern of plasma [cortisol]?
Highest in the morning, lowest at midnight
What drug can be used to treat prolactinoma?
Dopamine receptor agonist