Endo - Hypopituitarism

Question 1

What is hypopituitarism?

Answer 1

lack of pituitary function that can cause secondary failure of other glands

Question 2

What other glands can hypopituitarism effect?

Answer 2

Thyroid, adrenal cortex, gonads

Question 3

What is primary hypothyroidism? Effects on hormone levels?

Answer 3

→ damage or lack of function of thyroid

→T4 / T3 decrease, TSH increase

Question 4

What is secondary hypothyroidism? Effects on hormone levels?

Answer 4

→ damage to pituitary thyrotrophs

→ T3 + T4 decrease, TSH decrease

Question 5

What is primary hypoadrenalism? Effects on hormone levels?

Answer 5

→ damage or lack of function of adrenal cortex
→ low levels of cortisol
→ normal to high levels of ACTH

Question 6

What is secondary hypoadrenalism? Effects on hormone levels?

Answer 6

→ damage to pituitary corticotrophs

→ ACTH decreases, cortisol decreases

Question 7

What is secondary hypogonadism? Effects on hormone levels?

Answer 7

→ damage to pituitary gonadotrophs

→ LH + FSH decreases, testosterone + oestrogen decreases

Question 8

What is primary hypogonadism? Effects on hormone levels?

Answer 8

→ damage or lack of function of gonads
→ low levels of testosterone + oestrogen
→ normal to high levels LH + FSH

Question 9

What is a very rare cause of hypopituitarism?

Answer 9

→ congenital

Question 10

What is congenital hypopituitarism caused by?

Answer 10

Mutations of transcription factor genes needed for anterior pituitary development e.g. PROP1

Question 11

What symptoms does congenital hypo pituitarism present with?

Answer 11

→ deficiency of GH + at least 1 other AP hormone
→ short stature
→ hypoplastic (underdeveloped) AP gland on MRI

Question 12

What are 8 causes of acquired hypopituitarism?

Hint: TRIP TIPP

Answer 12

Traumatic brain injury
Radiation
Infection
Pituitary surgery

Tumours
Inflammatory (Hypophysitis)
Pituitary Apoplexy
Peri-partum Infarction

Question 13

What is total loss of anterior + posterior pituitary function called?

Answer 13

Panhypopituitarism

Question 14

What is most likely to cause panhypopituitarism?

Answer 14

Pituitary surgery + inflammation (hypophysitis)

Question 15

How does radiotherapy induce hypopituitarism?

Answer 15

→ pituitary + hypothalamus very sensitive to radiation
→ can be direct e.g. treating acromegaly
→ indirect eg treating nasopharyngeal carcinoma

Question 16

What parts of the pituitary are most sensitive to radiation?

Answer 16

Somatotrophs + gonadotrophs

Question 17

What hormone’s production can increase after radiotherapy? Why?

Answer 17

Prolactin

→ hypothalamic dopamine not produced due to radiation + damage

Question 18

How long can the risk of hypopituitarism persist after radiotherapy?

Answer 18

10 years

Question 19

How does hypopituitarism present with FSH/LH?

Answer 19

→ reduced libido
→ reduced pubic hair
→ secondary amenorrhoea (women)
→ erectile dysfunction (men)

Question 20

How does hypopituitarism present with ACTH + TSH?

Answer 20

→ fatigue

Question 21

How does hypopituitarism present with GH?

Answer 21

→ reduced quality of life

→ short stature in children

Question 22

How does hypopituitarism present with prolactin?

Answer 22

→ inability to breastfeed

Question 23

What is another name for peri-parturm infarction?

Answer 23

Sheehan’s syndrome

Question 24

What is the pathogenesis of Sheehan’s syndrome?

Answer 24

→ anterior pituitary enlarges during pregnancy due to lactotroph hyperplasia
→ haemorrhage / loss of blood during pregnancy = hypotension
→ pituitary infarction occurs (posterior usually not affected)

Question 25

What are symptoms of Sheehan's syndrome?

Answer 25

``` → lethargy + anorexia + weight loss (TSH, ACTH and GH deficiency) → failure to lactate (prolactin deficiency) → failure to resume menstruation (LH + FSH deficiency) ```

Question 26

What is pituitary apoplexy?

Answer 26

intra pituitary haemorrhage (or less commonly an infarction)

Question 27

What pre-existing condition is commonly associated with pituitary apoplexy?

Answer 27

Pituitary adenoma

Question 28

What can increase the likelihood of pituitary apoplexy?

Answer 28

Anti-coagulants

Question 29

What are symptoms of pituitary apoplexy?

Answer 29

→ severe sudden onset headache → visual field defect e.g. bitemporal hemianopia (due to compressed optic chiasm) → cavernous sinus involvement may lead to diplopia (double vision,IV, VI) + ptosis (droopy eyelid, Ill)

Question 30

How do you diagnose hypopituitarism radiologically?

Answer 30

MRI

Question 31

Why is MRI better than CT at identifying hypopituitarism?

Answer 31

→ CT not very good at delineating pituitary gland | → MRI can reveal specific pituitary pathology

Question 32

Why do you have to be careful when measuring cortisol?

Answer 32

Diurnal rhythm so depends on time of day | → highest in the morning

Question 33

Why do you have to be careful when measuring T4?

Answer 33

Circulates with a half life of 6 days

Question 34

Why do you have to be careful when measuring FSH/LH?

Answer 34

Cyclical in women

Question 35

Why do you have to be careful when measuring GH + ACTH?

Answer 35

pulsatile release

Question 36

How do you measure GH + ACTH release to determine a functioning pituitary?

Answer 36

Induce hypoglycaemia stress w INSULIN | → causes GH + ACTH release

Question 37

What is the name of the test that measures GH + ACTH?

Answer 37

Dynamic Pituitary Function Test

Question 38

What anterior pituitary hormone isn't treated?

Answer 38

Prolactin deficiency

Question 39

How is GH deficiency treated?

Answer 39

Daily injection (administered after DPF test and QOL questionnaire)

Question 40

How is the response to GH treatment measured?

Answer 40

→ improvement in QOL | → plasma IGF-1

Question 41

How is TSH deficiency treated?

Answer 41

Daily Levothyroxine, aiming for fT4 above the middle of reference range

Question 42

How is ACTH deficiency treated?

Answer 42

Replace cortisol with synthetic glucocorticoids | prednisolone or hydrocortisone

Question 43

What are the sick day rules for ACTH deficiency?

Answer 43

Take double dose of glucocorticoids | → when sick body normally produces more cortisol

Question 44

How is FSH/LH deficiency treated in men (no fertility)?

Answer 44

``` replace testosterone (topical gel or intra muscular) → does not restore sperm production ```

Question 45

How is FSH/LH deficiency treated in men (who want fertility)?

Answer 45

Gonadotrophin injections → best if hypogonadism is after puberty → may take 6-12 months til sperm

Question 46

How is FSH/LH deficiency treated in women (who want fertility)?

Answer 46

Carefully timed gonadotrophin injections (IVF) can induce ovulation

Question 47

How is FSH/LH deficiency treated in women (no fertility)?

Answer 47

→ oestrogen (oral tablets or topical gel) | → progesteron if uterus intact (to prevent endometrial hyperplasia)