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BRS Year 2 > Hypopituitarism > Flashcards

Hypopituitarism Flashcards

1
Q

What hormones are found in the anterior pituitary and what is their role?

A 
Growth hormone- growth
Prolactin- milk production
Thyroid stimulating hormone- T3 and T4
LH and FSH- oestrogen and progesterone
Adrenocorticotropic hormone- cortisol
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2
Q

What is the hypothalamo-pituitary system?

A

Hypothalamic releasing or inhibitory factors travel own the portal circulation to the anterior pituitary to regulate anterior pituitary hormone function

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3
Q

What can anterior pituitary failure affect?

A

Thyroid
Adrenal Cortex
Gonads

Can fail due to primary disease (gland fails) or secondary disease (no signal from hypo or ant. pituitary)

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4
Q

What are the consequences of primary hypothyroidism?

A

E.g. autoimmune destruction of thyroid gland

T3 and T4 fall but TSH increases

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5
Q

What are the consequences secondary hypothyroidism?

A

E.g. pituitary tumour damaging thyrotrophs
Cant make TSH
TSH falls
T3 and T4 fall

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6
Q

What are the consequences of primary hypoadrenalism?

A

E.g. destruction of adrenal cortex
Cortisol falls
ACTH increases

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7
Q

What are the consequences of secondary hypoadrenalism?

A

E.g. pituitary tumour damaging corticotrophs
Can’t make ACTH
ACTH falls
Cortisol falls

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8
Q

What are the consequences of primary hypogonadism?

A

E.g. destruction of testes or ovaries
Testosterone/ oestrogen fall
LH and FSH increase

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9
Q

What are the consequences of secondary hypogonadism?

A

E.g. pituitary tumor damaging gonadotrophs
Can’t make LH/FSH
LH and FSH fall
Oestrogen and testosterone fall

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10
Q

What are causes of hypopituitarism?

A

Congenital:

Rare and usually due to mutations of transcription factor genes needed for normal anterior pituitary development

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11
Q

What is an example of a congenital cause of hypopituitarism?

A

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

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12
Q

What are acquired causes of hypopituitarism?

A

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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13
Q

What do we call total loss of anterior and posterior pituitary function?

A

Panhypopituitarism

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14
Q

How can radiotherapy induce hypopituitarism?

A

Pituitary and hypothalamus are both sensitive to radiation
GH and gonadotrophs are most sensitive
PRL (prolactin) can increase after radiotherapy (loss of hypothalamic dopamine)
Risk persists up to 10 years after radiotherapy so annual assessment required

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15
Q

How does hypopituitarism present?

A 
FSH/LH:
Reduced libido
Secondary amenorrhoea
Erectile dysfunction
Reduced pubic hair

ACTH:
Fatigue
NB Not a salt losing crisis (reninangiotensin)

TSH:
Fatigue

GH:
Reduced quality of life
NB short stature only in children

PRL:
Inability to breastfeed

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16
Q

What is sheehan’s syndrome?

A 
Postpartum hypopituitarism secondary to hypotension (due to postpartum haemorrhage) 
It's more common in developing countries
Anterior pituitary enlarges in pregnancy
(lactotroph hyperplasia)
PPH leads to pituitary infarction
17
Q

What are 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
18
Q

What is pituitary apoplexy?

A

Intra-pituitary haemorrhage or (less commonly) infarction (obstruction of blood)
There’s often a dramatic presentation in patients with pre-existing pituitary tumours
It may be the first presentation of pituitary adenoma
Can be caused by anticoagulants

19
Q

What are symptoms of a pituitary apoplexy?

A

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

20
Q

How is hypopituitarism diagnosed?

A

You need to take caution when looking at basal plasma hormone concentrations:

  • Cortisol – what time of day?
  • T4 – circulating t1/2 6 days (half life)
  • FSH/LH – cyclical in women
  • GH/ACTH - pulsatile
21
Q

How would you measure ACTH and GH hormones?

A

These are pulsaile so you have to take dynamic measurements
Since ACTH and GH are stress hormones we can induce stress by making the patients hypoglycaemic- this releases GH and ACTH

22
Q

How would I stimulate TSH and FSH/LH release?

A

TRH stimulates TSH release

GnRH stimulates FSH & LH release

23
Q

What hormone can we not restore in hypopituitarism?

A

Prolactin

24
Q

How is GH deficiency treated?

A

You would confirm GH on a dynamic pituitary function test
You would then assess the quality of life using a specific questionnaire
If low QoL, prescribe daily injection

Measure response by
• improvement in QoL
• plasma IGF-1

25
Q

How does treating GH deficiency differ in children and adults?

A

In children its easier to treat

In adults its harder as we’re not sure of the role of GH in adults

26
Q

How is TSH deficiency treated?

A

Replace with once daily levothyroxine:

  • Don’t forget, TSH will be low (as hypo is damaged), 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
27
Q

How is ACTH deficiency treated?

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

28
Q

Whats the importance of sick day rules for patients with ACTH deficiency?

A

Patients with ACTH are at risk of adrenal crisis triggered by intercurrent illness

Symptoms of adrenal crisis: dizziness, hypotension, vomiting, weakness and collapse and death

Patients who take repleacent steroids must be told sick day rules

29
Q

What are the sick day rules?

A

• 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

30
Q

How is LH/FSH deficiency treated in men?

A

If no fertility is required:
Replace testosterone – topical or
intramuscular most popular
• Measure plasma testosterone
• Replacing testosterone does not restore
sperm production (this is dependent on FSH)

If fertility is required:
•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

31
Q

How is LH/FSH deficiency treated in women?

A

If no fertility required:
• Replace oestrogen
• Oral or topical
• Will need additional progestogen if intact uterus to prevent endometrial hyperplasia

If fertility required:
• Can induce ovulation by carefully timed gonadotropin injections (IVF)

BRS Year 2 (110 decks)

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