Pituitary Adenomas Flashcards
Where are pituitary adenomas derived from?
cells of the anterior pituitary
What is the genetic defect that can predispose to pituitary adenomas?
MEN-1 - Werner Syndrome
What is the most common pituitary adenoma?
prolactinoma
What can large adenomas cause?
visual field defects
infarction
pressure atrophy
What are the 3 types of pituitary adenomas?
Prolactinoma
Growth hormone secreting –> Acromegaly
ACTH secreting –> cushings
What is the most common pituitary adenoma?
prolactinoma
How does a prolactinoma present in females?
galactorrhea - increased milk production early presentation menstrual abnormalities ammenorrhoea infertility
How does a prolactinoma present in males?
impotence - erectile dysfunction visual field abnormailites late presentation headache anterior posterior malfunction
What drugs can also cause an increased prolactin?
dopamine antagonists - metoclopramide
antipsychotics - phenothiazine
antidepressants
What are the investigations done for a prolactinoma?
serum prolactin concentration - raised
MRI of brain
test visual fields
pituitary function tests
What is the visual deformity that can occur due to a prolactinoma?
bitemporal hemianopia - tunnel vision
What are the treatment for prolactinomas?
DOPAMINE AGONISTS e.g.
- Cabergoline - 1 or 2 daily
- Bromocriptine - 3 daily
- Quinagolide - 1 daily
Why are dopamine agonists used to treat prolactinomas?
dopamine inhibits PRL
What does a growth hormone producing tumour result in?
Acromegaly
What are the presenting features of acromegaly?
enlarged forehead, hands, feet and jawline prominent brow thickened soft tissue hypertension cardiac failure snoring and sleep apopnea headaches - stop as soon as treated colonic polyps pituitary affects - visual disturbances
What is the first diagnostic test for acromegaly?
IGF-1
What is the second but gold standard diagnostic test for acromegaly?
GGT suppression test - (glucose tolerance test)
GH <0.4 = fine GH >1 = needs treatment
What are other additional tests for acromegaly?
MRI pituitary
pituitary function tests
visual fields
How is acromegaly pharmacologically treated?
- Somatostatin analogues
- Sandostatin, lanreotide, pasireotide
suppress GH production, can be used post op to releive headaches - Dopamine agonists
- Cabergoline
- only works in 15% of patients - GH antagonists
- Pegvisomant: binds to the GH receptor, blocking GH activity
- doesnt decrease tumour size
What are the side effects of somatostatin analogues?
inhibit gut hormones
stops bladder contracting causing gallstones
What are the non pharmacological treatments of acromegaly?
pituitary surgery - 90% cure if micro, 50% if macro
external radiation to the pituitary fossa - 25% sucess
What is the difference between cushings disease and syndrome?
disease = caused by ACTH over secretion syndrome = the signs and symptoms that are caused by excess cortisol in the body
What is the general presentation of cushings?
muscle wasting - myopathy
osteoporosis - leaking of protein out of bones
thin skin
striae
moon face
central obesity
hypertension and oedema -> mineralocorticoid
acne, hirtism, amenorrhea -> excess androgens
conjunctival oedema -> chemosis
depression
buffalo fat pad
How is cushings screened?
overnight dexamethasone suppression test
cortisol > 100 = abnormal
What is the definitive cushings test?
2 day 2mg Dexamethasone suppression test (low dose)
What results of the low dose dexamethasone test would indicate cushings?
cortisol >130 mol/L after 6 hours of last dose
What is dexamethasone?
oral high dose steroid
Why do people with cushings have a high mortality?
steroids are immunosuppressive
What is the non pharmacological treatment for cushings if it is a pituitary cause?
pituitary surgery = hypophysectomy and external radiotherapy if it reoccurs
What is the non pharmacological treatment for cushings if it is a adrenal cause?
adrenalectomy
What is the non pharmacological treatment for cushings if it is a ectopic cause?
remove source
What is the pharmacological treatment for cushings?
Metyapone - if other treatments fail
Ketocanazole - hepatotoxic
Pasireotide - somatostatin analogue
What are the non pituitary causes of cushings syndrome?
adenoma/carcinoma of the adrenal glands
ectopic ACTH from lung cancers, thymus etc
pseudocushings - steroid meds, alcohol, depression
prolonged high dose steroid therapy >2 weeks
What are the 3 causes of pituitary hypofunction?
sarcoidosis - granulomatous inflammation
sheehans syndrome - infarction
primary or metastatic tumours
What is a craniopharyngioma dervied from?
remnant of Rathkes pouch
How does a craniopharyngioma present?
headaches
visual disturbances
How is a craniopharyngioma treated?
radiation
