Hypopituitarism Flashcards
Distinguish between primary and secondary disease
Primary is where the gland itself is affected
Secondary is where there is an issue with signalling from the hypothalamus or pituitary gland
What is primary hypothyroidism?
Autoimmune destruction of thyroid gland - Hashimoto’s
T4/3 low, TSH high
What is secondary hypothyroidism?
Pituitary tumour affecting thyrotrophs so no TSH
TSH, T4/3 all low
What is primary hypoadrenalism?
Autoimmune destruction of adrenal glands
Low cortisol, high ACTH
What do CRH levels look like in primary hypoadrenalism?
They would be high but it’s difficult to measure
What is secondary hypoadrenalism?
Pituitary tumour affecting corticotrophs so low ACTH & cortisol
What is primary hyopogonadism?
Destruction of the testes by mumps or ovaries by chemotherapy. Results in low oestrogen/testosterone and high LH/FSH
What is secondary hypogonadism?
Pituitary tumour affecting gonadotrophs. Results in low oestrogen, testosterone, LH & FSH
Explain the congenital causes of hypopituitarism
It’s rare and caused by a mutation in the TFs that are involved in anterior pituitary development.
Deficiency in growth hormone and one other AP hormone
Signs of hypopituitarism
short stature and hypoplastic pituitary gland on MRI (underdeveloped)
Causes of acquired hypopituitarism
Tumours
Infection
Surgery
Radiation
Pituitary surgery
Hypophysitis (inflammation)
Pituitary apoplexy - haemorrhage or infraction
Peri-partum infarction (Sheehan’s syndrome)
Name of total loss of pituitary function
Panhypopituitarism
Presentations of low FSH/LH
Secondary amenorrhoea
Reduced libido
Reduced pubic hair
Erectile dysfunction
Presentation of low PRL
Inability to breastfeed
Presentation of low ACTH
Fatigue
NOT a salt losing crisis because aldosterone is under control by renin-angiotensin
Presentation of low TSH
Fatigue
Presentation of low GH
Short stature IN CHILDREN
Reduced QoL
What happens to the anterior pituitary during pregancy?
It enlarges aka lactotroph hyperplasia
What is Sheehan’s Syndrome?
Post-partum haemorrhage leads to infarction, often secondary to hypotension
Most common in developing countries
Signs/Symptoms of Sheehan’s
Inability to resume menses
Lethargy, weight loss, anorexia
Issues with lactation
What is pituitary apoplexy?
Haemorrhage or infarction to pituitary gland often inidcates a pituitary adenoma
Medical term for double vision
Diplopia
What kind of medication precipitates pituitary apoplexy?
Anti-coagulants (blood thinners)
Presentation of pit. apoplexy
Severe headache
Bitemoporal hemianopia
Diplopia
Ptosis (drooping of upper eyelid)
What is a dynamic pituitary function test?
Where hypoglycaemic stress is induced by administering insulin.
GH/ACTH are released in response to stress and are measures
TRH and GnRH cause TSH & LH/FSH release respectively
Treatment of GH deficiency
Daily injection of GH
Measure QoL and see if there is improvement
Plasma IGF-1 measured
Treatment of TSH deficiency
Replace with levothyroxine
in secondary hypothyroidism aim for a T4 above the middle of the reference range
Treatment of ACTH deficiency
Replace cortisol rather than ACTH
Give synthetic glucocorticoids like hydrocortisone (3x daily) or prednisolone (once daily)
Features of adrenal crisis
Vomiting, dizziness, hypotension, may even collapse and die
Sick day rules for ACTH deficiency
Wear steroid bracelet
Double dose of glucocorticoids
Inject intramuscularly (vomiting means they can’t take it orally)
Treatment of FSH/LH deficiency (men - no fertility)
Topical or intramuscular injections of testosterone
Testosterone will not cause spermatogenesis
Treatment of FSH/LH deficiency (men - fertility)
Induce spermatogenesis by gonadotropin injections
Best response if secondary hypogonadism occurs AFTER puberty
Treatment of FSH/LH deficiency (women - no fertility)
Administer oestrogen orally or topically
Progesterone also needed
Why is progesterone needed alongside oestrogen?
To prevent endometrial hyperplasia if the womb is intact
Treatment of FSH/LH deficiency (women - fertility)
Gonadotropin injections needed to induce ovulation - IVF
