Hyposecretion of Anterior Pituitary Hormones Flashcards
Name the 5 hormones secreted by the adenohypophysis
Gonadotrophin (LH and FSH), somatrophin (GH), prolactin, thyrothrophin (TSH) and corticotrophins (ACTH)
Where is a primary endocrine disease situated, give an example of a site
In the endocrine gland (e.g. thyroid gland)
Where is a secondary endocrine disease situated
In the pituitary
Where is a tertiary endocrine disease site
Hypothalamus
What is panhypopituitarism?
Insufficient excretion of all adenohypophysial hormones
Which level of hypopituitarism is most common and least (primary/secondary/tertiary)
Primary is most, tertiary is least
How common is congenital panhypopituitarism
Rare
What mutation causes congenital panhypopituitarism
PROP1
What is PROP1
Transcription factor that allows the development of the pituitary gland to take place
Which hormone does a congenital PROP1 mutation always affect?
Growth hormone
What is he presentation of congenital hypopituitarism (2)
Short stature and a hypoplastic pituitary on an MRI
What things cause hypopituitarism (9)
Congenital Tumours chemotherapy radiation infection traumatic brain injury Infiltrative disease Inflammation Pituitary apoplexy Peri-partum infarction
What are hypothalamic tumours known as
Craniopharyngiomas
What are pituitary tumours known as
Adenomas
What type of cancer tends to metastasise to the pituitary
Breast
What else is similar to a tumour that can compress the pituitary
Cysts
Which secretion/hormone is most and least resistant to damage via radiotherapy
Most is GH least is TSH
Which microorganism can infect and cause pituitary pathology
Meningitis
What is an example of an infiltrative disease? Which part of the physiology of the pituitary is used
Sarcoidosis, pituitary stalk
What is a pituitary apoplexy
Damage from bleeding
What is peri-partum infarction known as
Sheehans syndrome
What are the three types of hypopituitarism
Simmonds disease (normal hypopituitarism)
Sheehans syndrome
Pituitary apoplexy
What is an FSH/LH deficiency known as
Secondary hypogonadism
What is an ACTH deficiency known as
Secondary hypoadrenalism
What is a TSH deficiency known as
Secondary hypothyroidism
What symptoms are associated with secondary hypogonadism
Reduced libido, secondary amenorrhoea, erectile dysfunction
What symptoms are associated secondary hypoadrenalism
Fatigue
What symptoms are associated with secondary hypothyroidism
Fatigue (everything slows down)
What is panhypopituitarism also known as
Simmonds disease
What is simmonds disease more commonly known as
panhypopituitarism
Who can be affected by sheehans syndrome
Only women
Explain sheehans syndrome. Give cause + effect for three sciencey words at end
Lactotroph hyperplasia occurs during pregnancy making the pituitary bigger. Post-partum hypotension (e.g. due to post-partum haemorrhage) means the pituitary is severely deoxygenated due restricted blood flow bc the increased size is compressing the stalk.
Pituitary infarction -> ischaemia -> necrosis
Where are all the blood vessels that oxygenate the pituitary found
Travelling down the stalk
Where is sheehans syndrome less common
In developed countries due to improves obstetrics
What are the symptoms of sheehans syndrome, and explain the symptoms regarding weight
Tiredness, anorexia, weight loss(lack ACTH outweighs the hypothyroidism), failure of lactation, failure of menses resuming
Which parts of the pituitary are affected by sheehans syndrome
Only the adenohypophysis, neurohypophysis is usually completely unaffected
What are the differences netween sheehans syndrome and a pituitary apoplexy
Pituitary apoplexy is not specific to women and presentation is rapid
What can cause pituitary apoplexy
Pituitary adenomas infarcting or intra-pituitary haemorrhage
What can precipitate a pituitary apoplexy
Anti-coagulants
What is the first rapid presentation of a pituitary apoplexy
Headache
Explain how a pituitary apoplexy can cause bitemporal hemianopia
Pituitary sits just below the optic chiasm, expansion can compress the optic chiasm causing bitemporal hemianopia
Explain how a pituitary apoplexy can cause ptosis, mention nerve and area
Expansion of the pituitary can cause compression of CNIII
What is ptosis
Droopy eyelid
Explain how a pituitary apoplexy can cause diplopia, mention the area and the nerves compressed
pituitary apoplexy can cause the pituitary to interfere with structures in the cavernous sinus such as CNIV and CNV
Are basal plasma levels of adenohypophysial hormones a useful indicator of hypopituitarism and why
No because the hormones released are pulsatile (LH, FSH, GH ACTH) and T4 has a half life of 6 days
What are stimulated dynamic pituitary function tests and what do you administer for each hormone
Administering a releasing hormone to stimulate release and then measuring levels
Insulin stimulates GH and ACTH release via lowering blood glucose
TRH stimulates TSH
GnRH stimulates LH and FSH
What radiological method would you use to diagnose panhypopituitarism
MRI
What technique is used to treat hypopituitarism
Hormone replacement therapy
When testing for suspected ACTH deficiency, which hormone do you test for and why
Cortisol because ACTH has a low plasma half-life
Replacement and check for deficienct ACTH
Hydrocortisone and check for serum cortisol
Replacement and check for deficient TSH
Thyroxine and check for serum T4
Replacement and check for deficient LH/FSH In women
Eostrogen plus progestogen, check for symptoms improvement and withdrawal bleeds
Replacement and check for deficient LH/FSH in men
Testosterone and check for symptom improvement and serum testosterone
Replacement and check for deficient GH
GH and check IGF1/use a growth chart in children
What are the consequences of prolactin deficiency in each gender
Men not that deep, women will be unable to breastfeed due to prolactin being critical for milk ejection
What has to be administered with oestrogen to women for secondary hypogonadism
Progestogen
What can happen to the female uterus if progestogen is not administered with oestrogen
Endometrial hyperplasia
What is given for men who have secondary hypogonadism, route of administration and how often
Testosterone injection every three months
What are 7 causes of short stature
Endocrine disorders, genetic causes, emotional deprivation, systemic disease, malnutrition, malabsorption, skeletal dysplasia
Where is the problem with Prader-Willi syndrome? What is affected? What’s it associated with? How to treat?
Hypothalamus, lack of GHRH, associated with obesity and learning difficulties, treatment with GH
Lack of which hormone causes pituitary dwarfism? When and how does this present? What are the causes?
GH, from childhood, pituitary won’t develop fully due to damage/genetic mutations
Achondroplasia is caused by a mutation in which protein?
Fibroblast growth factor 3 receptor (FGF3)
What is achondroplasia? How does it present?
Abnormality in growth plate chondrocytes, presents as short arms and legs but normal trunk
What is a chondrocyte
Cartilage cells
What is Laron dwarfism? How can it be treated?
Problems with the GH receptors on the liver, treated with IGF1
Why are random GH tests shit
Because GH release is pulsatile
Name the GH provocation tests (4)
Insulin, GHRH, glucagon and exercise
How does the insulin GH provocation test work
Insulin induces hypoglycaemia which stimulates the release of GH
What do you administer with the GHRH in the provocation test
Arginine
How does the glucagon provocation test work
Glucagon makes you feel ill, the stress of vomiting then induces glucagon release
In what population is the exercise provocation test useful for
Small children
What are the consequences of GH deficiency in adults
Reduces lean mass Increased adiposity Reduced muscle strength&bulk Decreased HDL and increased LDL Impaired psychological well-being
What are the risks of GH therapy (2)
Increased risk of cancer (but no evidence for this), and treatment costs £42k for an adult for all their life
