What is found superior to the pituitary gland?
Optic chiasm
The pituitary gland is split into which parts?
Anterior and posterior pituitary gland
What hormones are produced by the posterior pituitary?
ADH
Oxytocin
Which hormones are produced by the anterior pituitary gland?
ACTH
TSH
FSH
LH
PRL
Growth hormone
Which gland itself controls the pituitary gland?
Hypothalamus
What are the effects of cortisol?
Increases blood glucose level
Increased lipogenesis
Increases immune response
What is the main difference between prolactin release from the anterior pituitary and all the other hormones?
Dopamine inhibits constant prolactin secretion by the anterior pituitary
What are the three clinical presentations you see in endocrinology?
Too much hormone
Not enough hormone
Gland is too big
In which direction do pituitary tumours usually grow?
Superiorly
because inferiorly and laterally there are bones
What structure tends to be compressed by pituitary tumours?
Optic chiasm
If a pituitary tumour grows around the internal carotid artery, can it be cured surgically?
No, risk of rupturing artery too high
What ENT symptom may patients present with if a pituitary tumour breaches the sphenoid sinus?
CSF leak from nose
What dynamic tests would you do in the case of
a) too much hormone
b) too little hormone?
a) Too much > Suppression test
b) Too little > Stimuation test
Diabetes insipidus involves a deficiency of what?
ADH
What is the stimulation test for diabetes insipidus?
Water deprivation test
should stimulate the release of ADH
What name is given to pituitary tumours
a) < 1cm
b) > 1cm
in diameter?
< or equal to 1cm diameter - MICROADENOMA
> 1cm diameter - MACROADENOMA
What is a non-functioning pituitary adenoma?
A pituitary adenoma which doesn’t produce any hormone
What can non-functioning pituitary adenomas compress?
Optic chiasm
CN III, IV & VI (optic, trochlear, abducent nerves)
What endocrine conditions do non-functioning pituitary adenomas produce?
Not producing hormone, so deficiencies:
hypoadrenalism
hypothyroidism
hypogonadism
GH deficiency
If a non-functioning pituitary adenoma affects the posterior pituitary, what endocrine condition can you get?
Diabetes insipidus
At the optic chiasm, which optic nerves cross over and which ones stay on the unilateral side?
Temporal nerves stay on the same side
Nasal nerves cross over
Which type of vision is lost in optic chiasm compression?
Temporal vision on both sides
bitemporal hemianopia
What is the physiological function of prolactin?
Production of breast milk
What are physiological causes for a raised prolactin?
Breastfeeding
Pregnancy
Stress
Sleep
Which drugs cause raised prolactin?
Dopamine antagonists
Antipsychotic drugs
What is an example of a dopamine antagonist which raises prolactin?
Metoclopramide
How do dopamine agonists affect prolactin levels?
Suppress prolactin
Which thyroid-related hormone causes prolactin levels to rise?
Thyrotropin releasing hormone (TRH)
so PRL is raised in hypothyroidism
Which thyroid disease causes raised prolactin levels?
Hypothyroidism
as TRH levels are raised to compensate
What is a functioning adenoma which can cause raised prolactin?
Prolactinoma
How would you investigate a suspected prolactinoma?
Measure prolactin levels
MRI scan of pituitary gland
Visual field test (for bitemporal hemianopia)
Pituitary function test for other abnormalities
Are prolactinomas surgically removed?
No, high risk of damage to other structures
How is prolactinoma treated?
Dopamine agonists
to inhibit prolactin secretion
What is an example of a dopamine agonist used to treat prolactinoma?
Cabergoline 2x a week
What condition is caused by growth hormone excess?
Acromegaly
What is the presentation of acromegaly in children?
Giantism
After epiphyseal fusion, which structures grow in acromegaly?
Soft tissue (skin, jaw, hands)
Cardiovascular structures (hypertension, cardiac failure)
Does the pituitary tumour itself cause headaches seen in acromegaly?
NO
effect of vascular changes
What are respiratory symptoms of acromegaly?
Snoring
Sleep apnoea
What is a classic respiratory presentation of acromegaly?
Sleep apnoea
As GH is a stress hormone, what endocrine condition can it cause in the long term?
Diabetes
due to hyperglycaemia
As acromegaly is caused by a pituitary tumour, what optic problems can be involved?
Visual field disturbance
Which tests are used to diagnose acromegaly?
Measure IGF-1 levels
Oral glucose tolerance test
MRI pituitary
As acromegaly is caused by GH excess, what test is used to diagnose it?
Glucose tolerance test i.e a suppression test
Normally GH will decrease in response to hyperglycaemia, in acromegaly it doesn’t or it even increases
How is acromegaly treated?
Pituitary surgery
Radiotherapy
Somatostatin analogues
Which hormone inhibits the release of GH from the anterior pituitary and can be used in acromegaly pre and post-op?
Somatostatin
Which symptom of acromegaly can be treated quickly using somatostatin analogues?
Headache
How is somatostatin administered?
Injections
Why does somatostatin cause GI side effects, particularly gall stones?
Affects gut hormones inc. CCK, which controls gallbladder contraction
Why can dopamine agonists be used in acromegaly?
Some pituitary tumours secrete both PRL and GH
If all attempts to treat acromegaly fail, which drug can be tried to treat it?
GH antagonists
may increase GH by negative feedback, exacerbating the problem