Hypopituitarism

Question 1

What are the 5 anterior pituitary hormones?

Answer 1

Question 2

What regulates anterior pituitary hormone production? And where do they travel?

Answer 2

Question 3

What do each of the anterior pituitary hormones make?

Answer 3

Question 4

What glands can be affected if the anterior pituitary fails? What are the two different types of failure - explain?

Answer 4

Question 5

Describe primary hypothyroidism

Answer 5

Question 6

Describe secondary hypothyroidism

Answer 6

Question 7

Describe primary hypoadrenalism

Answer 7

Question 8

Describe secondary hypoadrenalism

Answer 8

Question 9

Describe primary hypogonadism

Answer 9

Question 10

Describe secondary hypogonadism

Answer 10

Question 11

What are the congenital causes of hypopituitarism and how can it be seen?

Answer 11

Question 12

What are the acquired causes of hypopituitarism and how can it be seen?

Answer 12

Question 13

What is hypophysitis? Where does it affect?

Answer 13

Inflammation (hypophysitis) that can cause anterior and posterior pituitary dysfunction. Surgery can also dysfunction

Question 14

What is panhypopituitarism?

Answer 14

Total loss of anterior & posterior pituitary function

Question 15

How does radiotherapy induce hypopituitarism?

Answer 15

Pituitary and hypothalamus both sensitive to radiation
Radiotherapy direct to pituitary eg hormone producing pituitary tumour or indirect eg CNS tumour nearby
Higher total radiotherapy dose (Gy), higher risk of HPA axis damage
GH and gonadotrophins most sensitive
Risk persists up to 10y after radiotherapy, so annual assessment

Question 16

What are presentations of secondary hypogonadism?

Answer 16

Lower FSH/LH
Reduced libido
Secondary amenorrhoea
Erectile dysfunction
Reduced pubic hair

Question 17

What are presentations of secondary hypoadrenalism?

Answer 17

Lower ACTH
Cortisol loss - Fatigue
NB Not a salt losing crisis (renin-angiotensin)

Question 18

What are presentations of secondary hypothyroidism?

Answer 18

Lower TSH
Fatigue
Long term - weight gain potentially

Question 19

What are presentations of low GH?

Answer 19

Reduced quality of life
NB short stature only in children

Question 20

What are presentations of lower PRL?

Answer 20

Inability to breastfeed

Question 21

What is Sheehan’s syndrome?

Answer 21

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

Question 22

What are presentations of Sheehan’s syndrome?

Answer 22

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

Question 23

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

Answer 23

MRI

Question 24

What is pituitary apoplexy?

Answer 24

Bleeding (haemorrhage) into the pituitary or loss of blood flow (infarction) to the pituitary
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 (blood thinners)

Question 25

What are the presentations of pituitary apoplexy?

Answer 25

Severe sudden onset headache Visual field defect – compressed optic chiasm, bitemporal hemianopia Cavernous sinus involvement may lead to diplopia (IV, VI), ptosis (III)

Question 26

What are biochemical diagnosis's of hypopituitarism?

Answer 26

Caution in interpreting basal plasma hormone concentrations Cortisol – what time of day? T4 – circulating t1/2 6 days FSH/LH – cyclical in women GH/ACTH - pulsatile

Question 27

What is a dynamic pituitary function test?

Answer 27

Used in the diagnosis of hypopituitarism 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

Question 28

What can a pituitary MRI show?

Answer 28

Pituitary MRI (CT not so good at delineating pituitary gland) May reveal specific pituitary pathology eg haemorrhage (apoplexy), adenoma Empty sella – thin rim of pituitary tissue

Question 29

How hormone can you not give if someone has hypopituitarism?

Answer 29

Prolactin

Question 30

How can GH deficiency be treated?

Answer 30

NICE guidance Confirm GH deficiency on dynamic pituitary function test Assess Quality of Life (QoL) using specific questionnaire Daily injection Measure response by : -improvement in QoL -plasma IGF-1

Question 31

How can TSH deficiency be treated?

Answer 31

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

Question 32

How can ACTH deficiency be treated?

Answer 32

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

Question 33

What are those with adrenal failure at risk of? How is this presented

Answer 33

Patients with primary adrenal failure (Addison’s) or secondary adrenal failure (ACTH deficiency) at risk of ‘adrenal crisis’ triggered by intercurrent illness Adrenal crisis features – dizziness, hypotension, vomiting, weakness, can result in collapse and death

Question 34

What are sick day rules?

Answer 34

Patients who take replacement steroid eg prednisolone, hydrocortisone must be told sick day rules -Steroid alert pendant/bracelet -Double steroid dose (glucocorticoid not mineralocorticoid) if fever/intercurrent illness -Unable to take tablets (eg vomiting), inject IM or come straight to A & E

Question 35

How can FSH/LH deficiency be treated if fertility is not required in men?

Answer 35

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

Question 36

How can FSH/LH deficiency be treated if fertility is required in men?

Answer 36

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

Question 37

How can FSH/LH deficiency be treated if fertility is not required in women?

Answer 37

Replace oestrogen Oral or topical Will need additional progestogen if intact uterus to prevent endometrial hyperplasia

Question 38

How can FSH/LH deficiency be treated if fertility is required in women?

Answer 38

Can induce ovulation by carefully timed gonadotropin injections (IVF)