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BRS Phase 1b > Hypopituitarism > Flashcards

Hypopituitarism Flashcards

1
Q

What are the 5 main hormones made by the anterior pituitary?

A 
Growth Hormone (Somatotrophin)
Prolactin
TSH ( Thyroid stimulating hormone)
LH, FSH - both gonadotrophin's
ACTH (Adrenocorticotrophic hormone)
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2
Q

What regulates the anterior pituitary hormone production?

A

Hypothalamic releasing or inhibitory factors travel in the portal circulation to regulate anterior pituitary hormone production.

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3
Q

What is primary disease?

A

gland itself fails, e.g. primary hypothyroidism

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4
Q

What is secondary disease?

A

no signals from hypothalamus or anterior pituitary, e.g. secondary hypothyroidism

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5
Q

What are congenital causes for hypopituitarism?

A

Rare, usually due to mutations of transcription factor genes needed for normal anterior pituitary development..
Would be deficient in GH and at least 1 more anterior pituitary hormone. Short stature, hypoplastic (underdeveloped APT on MRI).

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6
Q

What are the causes of Acquired hypopituitarism?

A

Much more common.
Tumours eg adenomas, metastases, cysts
Radiation (hypothalamic/pituitary damage)
Infection eg meningitis
Traumatic brain injury
Pituitary surgery
Inflammatory (hypophysitis)
Pituitary apoplexy - haemorrhage (or less commonly infarction)
Peri-partum infarction (Sheehan’s syndrome)

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7
Q

What is panhypopituitarism?

A

Total loss of anterior & posterior pituitary function.

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8
Q

How can you get hypopituitarism due to radiotherapy?

A

Pituitary and hypothalamus both sensitive to radiation. radiotherapy could be direct or indirect and damage done would be dependent on the dose delivered. Hormones that are most sensitive GH & gonadotrophin’s. Risk can persist for up to 10 years after therapy so yearly assessment is required.

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9
Q

Which hormone may actually increase as a result of radiotherapy damage to the hypothalamo-pituitary axis?

A

Prolactin, loss of hypothalamic dopamine which is an inhibitor.

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10
Q

What would a reduction in FSH/LH present as?

A

Reduced libido
Secondary amenorrhoea
Erectile dysfunction
Reduced pubic hair

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11
Q

What would a reduction in ACTH present as?

A

Fatigue

Not a salt losing crisis (renin-angiotensin)

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12
Q

What would a reduction in TSH present as?

A

Fatigue

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13
Q

What would a reduction in Growth hormone present as?

A

Short stature for children

Reduced quality of life

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14
Q

What would a reduction in Prolactin present as?

A

Inability to breastfeed

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15
Q

What is Sheehan’s syndrome?

A

Post-partum hypopituitarism secondary to hypotension (post partum haemorrhage - PPH)
More common in developing countries
Anterior pituitary enlarges in pregnancy (lactotroph hyperplasia)
PPH leads to pituitary infarction.

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16
Q

What is the presentation of Sheehan’s syndrome?

A

Lethargy, anorexia, weight loss – TSH/ACTH/(GH) deficiency
Failure of lactation – PRL deficiency
Failure to resume menses post-delivery
Posterior pituitary usually not affected

17
Q

What is the best radiological way to visualise the pituitary gland?

A

MRI

18
Q

What is pituitary apoplexy?

A

Intra-pituitary haemorrhage or (less commonly) infarction
Often dramatic presentation in patients with pre-existing pituitary tumours (adenomas)
May be first presentation of a pituitary adenoma
Can be precipitated by anti-coagulants

19
Q

What is the presentation for pituitary apoplexy?

A

Lethargy, anorexia, weight loss – TSH/ACTH/(GH) deficiency
Failure of lactation – PRL deficiency
Failure to resume menses post-delivery
Posterior pituitary usually not affected

20
Q

What is the best way to diagnose hypopituitarism?

A

Dynamic pituitary function test, taking a series of hormone measurements over a series of time points.

21
Q

What is measured in a dynamic pituitary function test?

A 
ACTH & GH = ‘stress’ hormones
Hypoglycaemia (<2.2mM)  = ‘stress’
Insulin-induced hypoglycaemia stimulates
	GH release
	ACTH release (cortisol measured)
TRH stimulates TSH release
GnRH stimulates FSH & LH release
So these would stay low in a patient with hypopituitarism.
22
Q

What is an empty sella?

A

no discernible pituitary tissue

23
Q

What is the treatment for Growth hormone?

A

Easier to determine in children harder in adults.
NICE guidance:
Confirm GH deficiency on dynamic pituitary function test
Assess Quality of Life (QoL) using specific questionnaire
Daily injection if low QoL
Measure response by
improvement in QoL
plasma IGF-1 - GH tells liver to make IGF-1.

24
Q

Why is the posterior pituitary not affected in Sheehan’s syndrome?

A

Origin is neural, not dependent on blood supply.

25
Q

Do pituitary adenomas predispose you to pituitary apoplexy?

A

yes

26
Q

Is the optic chiasm normally affected by lactotroph hyperplasia?

A

no, unless there is already a pituitary tumour that pushes against the optic chiasm.

27
Q

What is the treatment of TSH deficiency?

A

Straightforward
Replace with once daily levothyroxine
Don’t forget, TSH will be low, so you can’t use this to adjust dose as you do in primary hypothyroidism
Aim for a fT4 above the middle of the reference range

28
Q

What us the treatment for ACTH deficiency?

A

Replace cortisol rather than ACTH
Difficult to mimic diurnal variation of cortisol
Two main options in the UK using synthetic glucocorticoids
Prednisolone once daily AM eg 3mg
Hydrocortisone three times per day eg 10mg/5mg/5mg

29
Q

What are the features of an adrenal crisis?

A

dizziness, hypotension, vomiting, weakness, can result in collapse and death.

30
Q

What are patients with ACTH deficiency at risk of?

A

Adrenal crisis, triggered by intercurrent illness.

31
Q

What are the sick rules that patients who are on replacement steroids need to know?

A

Steroid alert pendant/bracelet
Double steroid dose (glucocorticoid not mineralocorticoid) if fever/intercurrent illness (body would normally make more cortisone in that situation)
Unable to take tablets (eg vomiting), inject IM or come straight to A & E

32
Q

What is the treatment of FSH/LH deficiency in men if fertility is required?

A

Replace testosterone – topical or intramuscular most popular
Measure plasma testosterone
Replacing testosterone does not restore sperm production (this is dependent on FSH)

33
Q

What is the treatment of FSH/LH deficiency in men if fertility is NOT required?

A

Induction of spermatogenesis by gonadotropin injections
Best response if secondary hypogonadism has developed after puberty
Measure testosterone and semen analysis
Sperm production may take 6-12 months

34
Q

What is the treatment of FSH/LH deficiency in women if fertility is NOT required?

A

Replace Oestrogen
Oral or topical
Will need additional progesterone if intact uterus to prevent endometrial hyperplasia.

35
Q

What is the treatment of FSH/LH deficiency in women if fertility is required?

A

Can induce ovulation by carefully timed gonadotrophin injections (IVF)

36
Q

Why is ACTH difficult to measure?

A

It’s not very stable in the bloodstream.

BRS Phase 1b (80 decks)

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