CLINICAL- ENDOCRINE, PITUITARY Flashcards
Where are vasopressin and oxytocin produced?
In the neurosecretory neurons of the Hypothalamus
They then travel to the pituitary where they can access the circulation
What is the clinical presentation of a pituitary tumour (rare!)?
Pressure effects from the tumour: vision can be disturbed as tumour may press on the optic chiasma
Pituitary failure
Hypersecretion of one or more hormones
How do surgeons access the pituitary gland?
Through the nose
Makes it easier than going through the brain
How could you correct the visual disturbance caused by a pituitary tumour?
Correct the pressure as it’s pushing on the optic nerves and chiasm
What are non functioning pituitary tumours?
They cause problems with where they are but they don’t actually produce any hormones
The tumour grows and presses on the pituitary gland and squashes it, looses it’s function, causes problems
These account for 90% of all pituitary tumours
Treatment is surgery and we aim to protect eyesight and restore function. There isn’t a pharmacological treatment!
What are functioning pituitary tumours?
These tumours will produce hormones
Most common are prolactinomas
There is pharmacological treatment available
What is a prolactinoma? What effects does it have?
A tumour that secretes prolactin
Is has pressure effects:
Headache, loss of peripheral vision
It has hormone effects:
Women get absent periods, infertility and galactorrhoea (nipple discharge)- therefore women symptoms are quite obvious!
Men: present with erectile dysfunction
How are prolactinomas treated?
Prolactin is naturally inhibited by release of dopamine from the hypothalamus.
Dopamine receptor agonists used- dopamine released- Fall in prolactin - Tumour shrinks
How long does it take with treatment for 40% of patients with prolactinomas to be in remission if tumours disappeared and prolactin now normal?
After 3 years of treatment with dopamine receptor agonists
Dopamine agonists used to treat prolactinomas include:
Cabergoline
Bromocriptine
Quinagolide
What are our concerns with these treatments?
They all require a baseline and then annual echocardiograms (ECG) apart from quinagolide
common side effects: nausea, fatigue, mood disturbance (patients therefore advised to take at night)
What happens with dopamine agonist drugs (for prolactinomas) in pregnancy??
Cabergoline has a long half life
So bromocriptine is preferred
Usually stope treatment in pregnancy unless tumour really big
Patient presenting with: Rings not being able to fit anymore bigger fingers Underbite (bottom jaw sticks out) Bigger feet Bigger nose Headaches Diabetes What could this be?
Acromegaly
A result of a pituitary tumour- gland produces an excess of growth hormone, body excessively grows
We ask people to bring in old photographs to compare!
What does gigantism (people are giants) result from?
growth hormone secreting pituitary tumours in childhood
What is somatostatin used for?
With acromegaly (increase in GH due to pituitary tumour) the first line treatment is SuRGERY
If this doesn’t work/ there’s no cure, somatostatin and it’s analogues can control growth hormone secretion.
Somatostatin is a growth hormone inhibitory hormone with a v short half life of 2 mins so not used
Octreotide and lanreoride are analogues that are used as their half life in 2 hours
What are octoreotide and lanreotide?
Somatostatin analogues used to treat acromegaly
They’re DEPOT INJECTIONS given once a month
Only shrink tumours in 30%
What medication related to the pituitary can cause gallstones?
The somatostatin analogues octoreotide and lanreotide
Can also cause nausea and diarrhoea and glucose intolerance
What is Pegvisomont and what is it used to treat?
The only available Growth Hormone receptor antagonist
It’s actually a mutated growth hormone with polymers attached to prolong it’s half life!
With this drug we monitor IGF-1, as Pegvisomont blocks the action of GH receptor to reduce the production of IGF-1 which goes on to produce growth
Pretty successful! 90% reduction in IGF-1 so less growth!
What’s the side effect with IGF-1 reducing drug Pegvisomont?
Hepatitis
What’s the main cause if Cushings on the wards?
steroid treatment!
How does cushings present?
Central obesity but thin arms and legs Bruising and thin skin Hypertension Diabetes Moon face Buffalo hump Low potassium Gastric ulcer Psychological- people go abit mad "steroid psychosis"
What’s the treatment for cushings?
Surgery
METYRAPONE given in preparation for pituitary surgery
This blocks hydrocortisone synthesis- to achieve normal cortisol
What hormone in excess causes cushings?
ACTH / cortisol
Cortisol levels are elevated by large amounts of ACTH.
If you have no cortisol, what does this cause?
Drop in blood pressure
Lowers your immune system
What mechanism are all hormones controlled by, including the pituitary, thyroid etc?
Negative feedback mechanism
METYRAPONE is given before surgery for Cushing’s/ the pituitary to get cortisol levels normal.
Why do we want normal cortisol before surgery?
To help with tissue wound healing
To reduce chance of infection before surgery
Big steroid doses suppress your immune system: this is not good before surgery so metyrapone helps get cortisol back on track so immune system is strengthened!
If the pituitary fails it’s sometimes removed in surgery. What effects can this have??
15% to patients will have major hormone defects
45% will be growth hormone deficient
So we need to replace these in the patient: the goal of replacement therapy is to mimic the normal body secretion as closely as possible
Why should hydrocortisone only be given as a replacement therapy?
It’s a short acting steroid
It only lasts 6 hours
Prednisolone can be used as a treatment in things like asthma etc
Who qualifies for growth hormone replacement?
NICE says adults with:
Stimulation test must prove Growth hormone deficiency
Low Quality of life (use AGDA score)
Must trial for 3-9 months and see an improvement in AGDA score
How do we monitor growth hormone replacement [recombinant growth hormone preparations]?
Monitor with IGF-1 (produced from growth hormone binding) Monitor symptoms (QoL AGDA score)
What’s the most common type of testosterone replacement therapy?
IM injections in bum every 3-14 weeks
Gels and tablets not very effective!
One of testosterone replacements sides effects is Polycythaemia. What is this?
An excess of red blood cells
Due to stimulated red blood cell production in the bone marrow
Can cause strokes as more Hb so blood more sticky!!
Does testosterone cause prostate cancer?
It doesn’t cause it
But there is increased risk of it so it fuels it
Side effects of testosterone (prostatism and Polycythaemia) should be monitored every 6 months
Is fludrocortisone used in pituitary failure?
No
Hydrocortisone is used to mimic cortisone levels
10mg morning, 5mg lunch, 5mg evening
Equivalent steroid doses:
What is 20mg oral hydrocortisone (the dose given to replace cortisol/ ACTH in pituatry failure) equivalent to?
5-7.5mg if prednisolone
0.75mg of Dexamethasone
These are small doses of steroids compared to other conditions,
Remember it’s a treatment dose, therefore smaller doses than usual!
This is just showing steroid equivalence because it shows how smaller amount of hydrocortisone we given as replacement therapy in pituitary failure
What are the HYDROCORTISONE sick day rules with fever (febrile illness) or a fractures limb?!!
Double the dose
What are the HYDROCORTISONE sick day rules with surgery???
IV hydrocortisone during surgery
Then double the dose