Pituitary Diseases Flashcards
(51 cards)
How can pituitary tumours be classified?
Microadenomas < or = 1cm
Macroadenomas > or = 1cm
functioning or non-functioning
What pituitary tumours are unlikely to present?
Small non-functioning tumours as unlikely to be producing any large amount of symptoms
What can large non-functioning pituitary tumours produce….
pressure effects or hormone deficiencies (hypo-pituitary)
Describe presentation of large non-functioning pituitary tumour?
LOCAL ANATOMICAL EFFECTS:
- bitemporal hemianopia
- damage to CN 2,3,4,5 and 6
- damage/ pressure on bony structures and meninges surrounding the fossa causing a headache
- pressure on hypothalamic centres causing altered appetite, obesity, thirst, somnolence/ wakefulness or precocious puberty
- interuption of CSF and CSF leak from nose
DEFICIENCIES OF HORMONES:
- usually affects the anterior pituitary
- hypothyroidism, hypogonadism, GH deficiency, hypoadrenalism
- unlikely diabetes insipidus
What must you check in someone with a pituitary tumour before operating?
Serum prolactin
What is prolactinoma?
Prolactin secreting adenoma of the pituitary gland
Presentation of prolactinoma?
Tends to present much earlier in women due to the nature of the symptoms: galactorrhea (lactation when not been pregnant), amenorrhoea and infertility
In men: impotence, visual field defects and headaches (as not noticed till large) and anterior pituitary malfunction
Who do prolactinomas tend to present earliest in?
Young women
Other than a prolactinoma what else can cause a rise in serum prolactin?
Physiological: breast feeding, pregnancy, stress and sleep
Drugs: dopamine antagonists e.g. metoclopramide, anti psychotics, antidepressants, oestrogen and cocaine
Pathological: Hypothyroid and stalk lesions
Why is it important to know about illicit drug use if high serum prolactin?
Cocaine can cause increase in serum prolactin
If serum prolactin is over _____ almost certainly a prolactinoma
5000
Investigations for prolactinoma?
serum prolactin and MRI pituitary
PREGNANCY TEST!!!
Pituitary function tests for other hormones affected
Treatment of prolactinoma?
Dopamine agonists are very effective and cause tumour shrinkage
Tend to use cabergoline
What causes acromegaly and gigantism?
Growth hormone excess
Almost all cases of acromegaly and gigantism are due to….
GH producing pituitary tumour- somatotroph adenoma
Usually occurs sporadically but gene mutations can give rise to familial forms
Describe gigantism and its features
Occurs in children before epiphyses have fused, execs GH stimulates hepatic secretion of ILGF-1. There is excess skeletal growth with bones retaining normal shape and relative proportions. Fusion of epiphysis is delayed but eventually occurs and features of acromegaly appear.
Describe acromegaly and its features?
Overgrowth of bone and soft tissue.
Features coarsened, enlarged nose
Projecting jaw
Irregular bone formation interferes with joints so get OA
Enlarged hands and feet
Pain from nerve compression
High BP with cardiac hypertrophy and may die of cardiac failure
2/3 fold increased risk of colonic cancer
Sleep apnoea
Investigations for acromegaly and gigantism?
Check IGF-1 Definitive test is glucose tolerance as normally should get suppression of GH but in acromegaly it will be unchanged Check MRI Check visual field Check other hormone functions
Definitive test for acromegaly?
Glucose tolerance as normally should get suppression of GH but in acromegaly it will be unchanged (as growth hormone counteracts blood glucose control of insulin so normally you would expect it to decrease in high blood glucose to allow insulin to do its job)
Describe the relationship between growth hormone and insulin?
Growth hormone (GH) counteracts in general the effects of insulin on glucose and lipid metabolism, but shares protein anabolic properties with insulin
Treatment of acromegaly and gigantism?
Trans-sphenoidal surgery is 1st line in most cases.
Patients with residual disease are offered drug treatment (somatostatin analogue> OCREOTIDE) to reduce GH and shrink tumour
Radiotherapy is last resort
Screening- cancer, CV risk factors, sleep apnoea
Which type of lung cancer can secrete ADH? How does this present?
Small cell lung cancer
Dilutional hyponaetremia
Which type of lung cancer can secrete ACTH causing Cushing’s syndrome?
Small cell lung cancer
Which type of lung cancer can cause hypercalcaemia and how? How does this present?
Squamous cell secretes parathyroid mimicking hormone so calcium is secreted. Will have a high serum calcium but undetectable parathyroid hormone.
