Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

endo > 1B hypopituitarism > Flashcards

1B hypopituitarism Flashcards

1
Q

What are the hormones the anterior pituitary makes?

A
  • Growth hormone (somatotrophin)
  • Prolactin
  • Thyroid stimulating hormone/thyrotrophin (TSH)
  • Gonadotrophins- Luteinising hormone (LH) and follicle stimulating hormone (FSH)
  • Adrenocorticotrophic hormone (ACTH, corticotrophin)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How does the hypothalamus control the anterior pituitary?

A

Hypothalamus produces releasing or inhibitory factors which travel in hypothalamo-pituitary portal system to anterior pituitary to regulate anterior pituitary hormone production

Portal system has leaky, fenestrated blood vessels: very rare- capillaries on both ends and doesn’t end at the heart

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the 2 types of anterior pituitary failure?

A
  • Primary disease- where the gland itself fails e.g. gonads, adrenal cortex, thyroid
  • Secondary disease- no signals from hypothalamus or anterior pituitary
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What happens in primary hypothyroidism?

A
  • Problem with thyroid gland- T3 and T4 fall, TSH increases because no -ve feedback
  • TRH would also be high but we don’t measure it
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is an example of primary hypothyroidism?

A

Hashimoto: autoimmune destruction of thyroid gland

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What happens in secondary hypothyroidism?

A
  • Problem with anterior pituitary or hypothalamus so TSH can’t be made
  • TSH falls → T3 and T4 fall
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is an example of secondary hypothyroidism?

A

Pituitary tumour damaging thyrotrophs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What happens in primary hypoadrenalism?

A
  • Problem with adrenal gland- cortisol falls, ACTH increases because no -ve feedback
  • CRH would also be high but we don’t measure it
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is an example of primary hypoadrenalism?

A

Autoimmune destruction of adrenal cortex e.g. Addison’s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What happens in secondary hypoadrenalism?

A
  • Problem with anterior pituitary or hypothalamus so ACTH can’t be made
  • ACTH falls → cortisol falls
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What happens in secondary hypogonadism?

A
  • Problem with anterior pituitary or hypothalamus so LH/FSH can’t be made
  • LH/FSH fall → Testosterone/oestrogen fall
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Give an example of primary hypogonadism

A

Destruction of testes (e.g. mumps) or ovaries (e.g. chemotherapy)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Give an example of secondary hypogonadism

A

Pituitary tumour damaging gonadotrophs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Which is more common out of acquired and congenital hypopituitarism?

A

Acquired hypopituitarism is much more common

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is congenital hypopituitarism?

A
  • Pituitary gland hasn’t developed properly in utero
  • Usually due to mutations of transcription factor genes needed for normal anterior pituitary development
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is an example of a gene mutation in congenital hypopituitarism?

A

PROP1 mutation
- Deficient in GH and at least 1 more anterior pituitary hormone
- Short stature
- Hypoplastic (underdeveloped) anterior pituitary gland on MRI

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What does hypopituitarism usually describe?

A

Anterior pituitary dysfunction

But, certain processes (esp inflammation- hypophysitis, or surgery) may cause posterior pituitary dysfunction too

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is panhypopituitarism?

A

Total loss of anterior and posterior pituitary function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are examples of acquired hypopituitarism?

A
  • Traumatic brain injury
  • Pituitary surgery
  • Tumours e.g. adenomas, metastases, cysts : ischaemic when squeezed against the sella turcica bone
  • Radiation (hypothalamic/pituitary damage)
  • Infection e.g. meningitis
  • Inflammatory (hypophysitis) (women: loss of periods; men: more difficult- loss of libido)
  • Pituitary apoplexy- haemorrhage (or less commonly infarction)
  • Peri-partum infarction (Sheehan’s syndrome)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How can radiotherapy cause hypopituitarism?

A
  • Pituitary and hypothalamus are both sensitive to radiation
  • Radiotherapy could be direct to pituitary e.g. to treat acromegaly
  • Radiotherapy could be indirect to pituitary e.g. to treat nasopharyngeal carcinoma- so pituitary is innocent bystander
10
Q

What happens to GH, gonadotrophins and PRL in radiotherapy-induced hypopituitarism?

A
  • GH and gonadotrophins are most sensitive to damage; first to go
  • PRL can increase after radiotherapy due to loss of hypothalamic dopamine
11
Q

What does the extent of damage from radiotherapy depend on?

A

Total dose of radiotherapy delivered to hypothalamo-pituitary axis

11
Q

How long does risk persist for after radiotherapy?

A

10 years, so annual assessment needed

12
Q

How does hypopituitarism present for FSH/LH?

A
  • Reduced libido; often not mentioned due to embarrassment
  • Secondary amenorrhoea —> ask abt libido
  • Erectile dysfunction —> ask abt libido
  • Reduced pubic hair
13
Q

How does hypopituitarism present for ACTH?

A
  • Fatigue

N.B. not a salt losing crisis (renin-angiotensin)

14
Q

How does hypopituitarism present for TSH?

A
  • Fatigue
  • Maybe weight gain
15
Q

How does hypopituitarism present for GH?

A
  • Reduced quality of life

N.B. short stature only in children

16
Q

How does hypopituitarism present for PRL?

A

Inability to breastfeed

17
Q

What is Sheehan’s syndrome?

A
  • Post-partum hypopituitarism secondary to hypotension (post-partum haemorrhage- PPH)
  • Anterior pituitary enlarges in pregnancy (lactotroph hyperplasia)
  • PPH leads to pituitary infarction
18
Q

What are the symptoms 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
19
Q

What happens to anterior pituitary during pregnancy?

A

It enlarges (lactotroph hyperplasia)

20
Q

What is pituitary apoplexy?

A
  • Intrapituitary haemorrhage or (less commonly) infarction
  • Often dramatic presentation in patients with pre-existing pituitary adenomas (tumours)
  • May be the first presentation of a pituitary adenoma
21
Q

What can the haemorrhage in pituitary apoplexy be precipitated by?

A

Anti-coagulants

22
Q

Describe this photo

A
  • White ball in middle is haemorrhage
  • C shaped grey thing on white ball is pituitary adenoma
  • Black/grey stripe thing on top of white ball and adenoma is optic chiasm
23
Q

What are the symptoms of pituitary apoplexy?

A
  • Severe sudden onset headache
  • Visual field defect- compressed optic chiasm (bitemporal hemianopia)
  • If blood enters cavernous sinus it could compress nearby cranial nerves causing eye movement problems:
    • Diplopia (double vision)- IV, VI
    • Ptosis- III
24
Q

What is important to keep in mind when measuring basal plasma hormone concs to diagnose hypopituitarism?

A
  • Cortisol- diurnal rhythm so time of day changes how much in blood
  • T4- has circulating half life of 6 days so might be normal on day of presentation but low a week later
  • FSH/LH- cyclical in women
  • GH/ACTH- pulsatile
25
Q

What is a dynamic pituitary function test?

A
  • Dynamic- taking a series of hormone measurements over a series of time points
  • ACTH & GH are stress hormones so we induce stress in patients by making them hypoglycaemic (<2.2mM) using insulin- look for:
    • GH increase
    • ACTH release (cortisol measured since ACTH is hard to measure)
  • Could give TRH to see whether anterior pituitary can make TSH
  • Could give GnRH to see if anterior pituitary can make LH/FSH
26
Q

How would we make a radiological diagnosis of hypopituitarism?

A
  • Pituitary MRI (CT not so good at delineating pituitary gland)
  • May reveal specific pituitary pathology e.g. haemorrhage (apoplexy), adenoma
  • Would see an empty sella- thin rim of pituitary tissue (empty sella syndrome: normal and functional)

Left pic shows anterior pituitary (grey) and posterior (white sliver) but right pic has empty sella

27
Q

How do we treat GH deficiency?

A
  • NICE Guidance for GH treatment
  • Confirm GH deficiency on dynamic pituitary function test
  • Assess quality of life (QoL) using specific questionnaire- GH role in adults is unclear but thought to be needed for psychological wellbeing
  • Daily injection
  • Measure response by improvement in QoL and plasma IGF-1
28
Q

How do we treat prolactin deficiency?

A

Not treatable

29
Q

How do we treat TSH deficiency?

A
  • Straightforward
  • Replace with once daily levothyroxine
  • In secondary hypothyroidism, TSH will be low so you can’t use this to adjust dose as you do in primary hypothyroidism
  • Aim for a fT4 (free T4) above the middle of the reference range
30
Q

How do we treat ACTH deficiency?

A
  • Replace cortisol rather than ACTH
  • Difficult to mimic diurnal variation of cortisol
  • 2 main options in the UK using synthetic glucocorticoids
    • Prednisolone once daily AM e.g. 3mg
    • Hydrocortisone three times per day e.g. 10mg then 5mg then 5mg
31
Q

What are the sick day rules for patients with ACTH deficiency?

A

Those with ACTH deficiency or Addison’s (primary adrenal failure) are at risk of adrenal crisis triggered by intercurrent illness e.g. UTI/chest infection

Patients taking replacement steroids e.g. prednisolone, hydrocortisone must be told sick day rules:
- Steroid alert pendant
- Double steroid dose (glucocorticoid not mineralocorticoid) if fever/intercurrent illness
- If unable to take tablets (e.g. vomiting), inject IM hydrocortisone or come straight to A&E

32
Q

Adrenal crisis features?

A
  • Dizziness
  • Hypotension
  • Vomiting
  • Weakness
  • Can result in collapse and death
33
Q

How is FSH/LH deficiency treated in men when no fertility is required?

A
  • Replace testosterone either topically or intramuscular
  • Measure plasma testosterone
  • Replacing testosterone doesn’t restore sperm production (this is FSH-dependent)
34
Q

How is FSH/LH deficiency treated in men when fertility is required?

A
  • Induction of spermatogenesis by gonadotrophin injections
  • Best response if secondary hypogonadism developed after puberty
  • Measure testosterone and semen analysis
  • Sperm production may take 6-12 months
35
Q

How is FSH/LH deficiency treated in women when no fertility is required?

A
  • Replace oestrogen
  • Oral or topical
  • Will need additional progestogen if uterus is intact to prevent endometrial hyperplasia
36
Q

How is FSH/LH deficiency treated in women when fertility is required?

A

Can induce ovulation by carefully timed gonadotrophin injections (IVF)

endo (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions