Pituitary Conditions Flashcards
What is the difference between functional and non-functional pituitary disease?
Functional - secretes excess hormone
Non-functional - results in decrease in hormone secretion
Despite pituitary adenomas being benign they can cause a wide range of symptoms.
At what point does a microadenoma become a macroadenoma?
Microadenoma = 1cm
Macroadenoma >/= 1cm
What 2 nearby structures can be compressed by a too large pituitary adenoma?
What does this lead to?
Optic chiasm
- Bitemporal haeminopia
Compress nerves found in cavernous sinus
- visual defects/ palsy of eye
What is the most common functional pituitary adenoma?
Prolactinoma
Aside from prolactinoma give 4 other reasons for a raised prolactin level?
- Physiological
- Pregnancy
- Breastfeeding
- Drugs (any drug that interferes with dopamine levels)
- metoclopramide
- antipsychotics (older styles)
- Lesions to pituitary stalk (prevent dopamine from being able to inhibit prolactin levels)
- Hypothyroidism
How is the pituitary gland imaged?
MRI
What drug is used to treat increased prolactin levels?
How does it work?
What effect does it have on the tumour?
Cabergoline (dopamine agonist)
Causes tumour to shrink
Why are women more likely to present early with prolactinoma compared to men?
Women have symptoms more quickly relating to increased prolactin levels
- amenorrhea (prolactin inhibits ovulation)
- galactorrhoea (spontaneous milk production)
Men
- impotence
- other hormone insufficencies
- visual defects
Why can a functional pituitary tumour cause a defect in other pituitary hormones?
It can become so large that it compresses on other areas of the pituitary gland and inhibits their secretion
Excess growth hormone can cause two types of condition depending on if it occurs in adults or children. What is the name of each?
Children - gigantism
Adults - acromegaly
What cancer is associated with acromegaly?
Colon cancer from polyp formation
Acromegaly can often cause headaches what is the most likely cause of these?
Vascular
How is acromegaly tested for?
Oral glucose tolerance test - GH should be suppressed
What is the typical characteristics of acromegaly?
Continued growth
- large hands
- large feet
- large lower jaw
- protrusion of forehead
Soft tissue swelling
- hands
- feet
- face
- tongue -> obstructive sleep aponea
Carpal tunnel syndrome
How is acromegaly managed?
- Transsphenoidal surgery
2. Somatostatin analogues e..g sandostatin
What is the most common cause of acromegaly?
Pituitary adenoma
Middle aged male patient presents with pallor, gynaecomastia, loss of facial and body hair and puffy face.
What investigations would you do and based on the most likely cause what would the treatment be?
Panhypopituritism
Test for all pituitary hormones
- cortisol @9AM
- testosterone @9AM
- LH + FSH (note these are v high in post-menopausal women)
- TSH + free T3+T4
- GH + IGF-1 = oral glucose test
Cortisol - hydrocortisone Testosterone - IM testoterone injections LH + FSH - oral contraceptive TSH + f/T3+T4 - levothyroxine GH + IGF-1 - GH SC injection nightly ADH - desmospression
What is the autoimmune condition that can occur post pregnancy that causes panhypopituitarism?
Sheenan
What is diabetes inspipidus?
What is commonly seen in the history?
Osmotic symptoms either caused by low production of ADH or kidneys poorly responding to ADH
Previous brain trauma
A patient is on ward who will drink anything and everything in sight, blood sugar levels are normal.
What test should now be done?
8hr water deprivation test
Patients drink loads and have very diluted urine
If then given desmopression and urine becomes more concentrated -> cranial DI (DI caused by low ADH production)
What are the side effects of synthetic testoterone treatment?
Polycythaemia (high conc. of RBC)
Prostate enlargement (not cancerous - but still has to be checked)
What cranial nerve is most commonly affected by pituitary adenoma?
How would this present?
III
Eye palsy - dilated pupil and down and out eyeball
Would a raised prolactin <1000 be suggestive of a prolactinoma?
No - needs to be raised significantly more than that - into the many thousands
What drug should be started first in panhypopituitrsim?
Hydrocortisone - avoid adrenal crisis
Which of the following is suggestive of DI:
- low plasma osmolality
- low urine osmolality
- low serum osmolality
Low urine osmolality
= dilute urine - not enough ADH to concentrate the urine
What effect does high prolactin have on other pituitary hormones?
Inhibits GnRH -> reduced FSH and LH
What condition is associated with the destruction of supraoptic nuclei in the hypothalamus?
Central DI
Define pituitary apoplexy
Bleed or obstruction of blood to the pituitary gland
Can arise from large tumour
Can men get galactorrhoea from increased prolactin?
Yes - although rare
More commonly present with gynaecomastia
What anti-nausea drug can cause raised prolactin levels?
Metoclopramide
