Flashcards in Pathology of the Pituitary Gland Deck (45):
What are the size classifications of pituitary tumours?
less/equal 1cm = microadenoma
>1cm = macroadenoma
What 2 structures can a non-functioning pituitary adenoma or a pituitary tumour compress?
Cranial Nerves 3,4,6
What cells are a pituitary adenoma derived form?
Cells from anterior pituitary
How are pituitary adenomas classified?
Cell type or hormone produced
What is the most common functional pituitary adenoma?
What are the other kinds of functional pituitary adenomas and what are their effects?
Growth hormone secreting adenoma - GH causes increase in IGF which stimulates growth of bone, cartilage and connective tissue giving gigantism or acromegaly
ACTH secreting adenoma - Leads to hypercortisolism, Cushing's disease
What % of pituitary tumours are pituitary carcinoma?
List some causes of panhypopituitarism.
1y or metastatic tumours
traumatic brain injury
surgery or radiation
infarction/ haemorrhage (Sheehans syndrome)
Decreased secretion of all of the pituitary hormones.
What is a carinopharyngioma derived from?
Remants of Rathke's pouch (makes anterior pituitary)
List 5 things about carinopharyngiomas.
Slow growing, often cystic, may calcify
Some arise within the sella but most suprasellar
Bimodal incidence (5-15, 60-70s)
Headaches and visual disturbances
Excellent prognosis - benign tumour
What are the 2 kinds of diabetes insipidus?
Central or nephrogenic
What is central diabetes insipidus?
Can be caused by trauma (including surgery), tumours and inflammatory disorders of hypothalamus and pituitary
What is nephrogenic diabetes insipidus?
Renal resistance to ADH effects
What does SIADH secretion mean?
Syndrome of Inappropriate ADH secretion
Ectopic production of ADH - paraneoplastic syndrome
With Acromagaly, which cancer are you at increased risk of?
How do non-functioning pituitary adenomas arise?
Sporadic or associated with MEN1
Give some causes of prolactinoma.
Physiological: pregnancy, breast feeding, stress, sleep
Drugs (dopamin antagonists, anti-psychotics, antidepressants, oestrogen, coccaine)
hypothyroidism (2y prolactinoma)
Pituitary stalk lesion
How does a prolactinoma arise in a female?
How does a prolactinoma present in a male?
visualy field abnormality
impotence or ED
Ant Pit malfunction
What investigations are required for a suspected prolactinoma?
Visual field (bitemporal hemianopia)
Pituitary function tests (several hormones)
How is a prolactinoma treated?
Dopamine agonists - Cabergoline, Metaclopramide - prolactin normaisation and tumour shrinkage
What treatment is required for acromegaly?
Retest GTT – if still>1mcg then needs drugs:
Somatostain analogues: Octreotide
Dopamine agonists: Cabergoline
GH antagonist: Pegvisomant
How does acromegaly present?
Thickened skin and enlarged jaw and facial aspects
Sleep apnoea/ snoring
Headaches – increased blood flow and tumour expansion
What causes acromegaly?
Anterior pituitary gland produces excess growth hormone
What is the definitive test for acromegaly?
glucose tolerance test: suppression test of GH – paradoxical rise in GH occurs: normal GH suppresses to 1mcg/l
What blood test can be useful in the aiding the diagnosis of acromegaly?
What can panhypopituitarism lead to?
GH -- growth failure
TSH -- hypothyroidism
LH/FSH -- hypogonadism
ACTH -- Hypoadrenal (ife-threatening)
ADH -- Diabetes Insipidus
Give some symptoms and signs of panhypopituitarism.
Loss of facial hair (M)
Loss of axillary and pubic hair
dry skin and hair
growth retardation (children)
What drugs can be given for panhypopituitarism?
GH (rarely given)
Testosterone for males (Sustanon, testogel)
What are the risks of testosterone replacement?
Prostate enlargment (not cancer)
Hepatitis (oral tabs only)
What can cause diabetes insipidus?
Familial – isolated or DIDMOAD
Acquired (idiopathic, RTA, surgery, skull #)
Rare (tumour, Sarcoid, meningitis, ext radiation)
What are the symptoms of DI?
Signs of dehydration (sometimes)
Blurred vision (rarely)
What are the symptoms of Cushing's disease?
Weight gain (central)
Conjunctival oedema (chemosis)
What causes primary Cushing's disease?
Ectopic ACTH (usually carcinoma - lung)
Name 3 causes of secondary Cushing's disease?
Alcohol – pseudocushing’s
What screening tests are used for Cushing's disease?
Dexamethasone 1mg overnight
24hr urinary free cortisol
Morning & midnight cortisol
What test is used to provide a definitve diagnosis of Cushing's disease?
Low dose dexamethasone
When Cushing's disease is caused by a pituitary adenoma, is it likely to be a micro or macro adenoma?
When Acromegaly is caused by a pituitary adenoma, is it likely to be a micro or macro adenoma?
A pituitary adenoma = 1cm is known as what?
What test is used to differentiate between the causes of Cushing's disease?
Short synacthen test
What are the 4 endocrine causes of HTN?
Chronic suppression of pituitary ACTH production and adrenal atrophy leads to what?
unable to respond to stress (illness/surgery)
need extra steroid when ill
CANNOT stop steroid suddenly - gradual