pituitary physiology & tumours Flashcards
what structures does a large non functioning pituitary adenoma compress?
optic chiasma
can compress other structures e.g. cranial nerves 3, 4 & 6
what is the management of pituitary non functioning adenoma that is compressing the optic chiasma?
transphenoidal surgery
replace hormones
what are causes of raised prolactin?
physiological - breastfeeding, pregnancy, stress, sleep
pharmacological- dopamine antagonists (e.g. metclopramide), antipsychotics (e.g. phenothiazines)
what are some pathological causes of raised prolactin?
hypothyroidism, stalk lesions, prolactinoma
what are the female symptoms of raised prolactin?
EARLY presentation
Galactorrhoea (milky nipple discharge)
Menstrual irregularity
Ammenorrhoea
Infertility
what are the male symptoms of raised prolactin?
LATE Presentation
Impotence
Visual field abnormal
Anterior pituitary malfunction
what investigations do you do fro prolactinoma?
serum prolactin concentration
MRI pituitary (is it too big?)
visual fields
pituitary function test to see if other hormones are affected
what is the most commonly used medication for for prolactinona?
dopamine agonists (cabergoline, bromocriptine, quinagolide)
what are the side effects of dopamine agonists?
nausea/vomiting
low mood
obsessive compulsive behaviour
what are the symptoms and effects of acromegaly- GH excess
thickened soft tissues - large hands, jaw
very tall
snoring / sleep apnoea
hypertension
headaches (vascular)
diabetes mellitus
local pituitary effects
early cv death
colonic polyps and colon cancer
what are the treatments for acromegaly?
pituitary surgery (90% cure if smaller than 1cm, 50% if bigger)
or radiotherapy alone
what drugs are used for acromegaly?
somatostatin analogues (sandostatin LAR or lanreotide)- reduces GH and shrinks tumour, relieves headache
what are the side effects of somatostatin analogues?
local stinging
short term flatulence, diarrhoea, abdo pain
long term- gallstones
what other types of drugs can be used for acromegaly
high dose dopamine agonists, GH antagonists
what other features should be managed in acromegaly?
cancer surveillance- colon and tubulo-villous adenoma
cv risk factors
sleep apnoea
what causes cushing’s syndrome?
excess cortisol
can result from pituitary tumours, taking long term corticosteroids, adrenal adenoma, ectopic ACTH production and alcohol and depression
what are the symptoms of cushing’s synrdome?
protein loss- myopathy, wasting, thin skin, osteoporosis
altered carbohydrate & lipid metabolism- obesity & diabetes mellitus
psychosis, depression
acne, hirsuitism, oglio/ameorrhoea
what are the diagnostic tests for cushing’s?
overnight 1mg dexamethasone suppression test - cortisol >130 = definitely cushing’s
urine free cortisol (24hr urine collection)
diurnal cortisol variation (8am compared to midnight) - loss of variation in cortisol levels between times of day suggests cushing’s
what is the name for cushing’s syndrome caused by a pituitary tumour?
cushing’s disease (all other types are cushing’s syndrome)
what is the treatment for cushing’s disease?
Hypophysectomy (Transsphenoidal route) and
external radiotherapy if recurs
Bilateral adrenalectomy
what is the treatment for adrenal cushing’s syndrome?
adrenalectomy
what is the treatment for ectopic cushing’s syndrome?
remove source or bilateral adrenalectomy
what are the drug treatment options for cushing’s?
not ideal-
metyrapone if other treatments fail or while waiting for radiotherapy to work
ketoconazole (but it is hepatotoxic)
pasireotide LAR (somatostatin analogue)
what are the main causes of hypopituitarism?
pituitary tumours
other local brain tumours
iatrogenic surgery
what are the symptoms of anterior hypopituitarism?
Menstrual irregularities
Infertility, impotence
Gynaecomastia
Abdominal obesity
Loss of facial hair
Loss of axillary and pubic hair
Dry skin and hair
Hypothyroid faces
growth retardation (children)
what is the treatment for hypopituitarism?
hormone rpelacement-
thyroxine, hydrocortisone, ADH, GH, sex steroids
what are the risks of testosterone replacement?
polycythaemia (high conc of rbcs) - risk of Mi and stroke
prostate enlargement
hepatitis - only in oral tablets
what are the benefits of GH replacement in adults?
Improves well being and Quality of life
Decreases abdominal fat
Increases muscle mass, strength, exercise capacity and stamina
Improves cardiac function
Decreases cholesterol and increases LDL
Increases bone density
Given by daily SC injection
what are the causes of cranial diabetes insipidus?
50% idiopathic
trauma, tumour, rarely familial
how do you diagnose cranial diabetes insipidus?
water deprivation test- NBM for 8-12 hours
then do stiumlation test and if it improves it is cranial DI
what is the treatment of diabetes insipidus?
desmospray, desmopressin tablets or injection
