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Endocrinology > Hypopituitarism > Flashcards

Hypopituitarism Flashcards

1
Q

List the hormones released by the adenohypophysis. (5)

A

Adenohypophysis = anterior pituitary

Releases: - 1 mark for each

1) LH/FSH
2) GH
3) TSH
4) ACTH
5) Prolactin

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2
Q

What hypothalmic neurons regulate the release of: (5)

1) LH/FSH
2) GH
3) TSH
4) ACTH
5) Prolactin

A

1) GnRH
2) GHRH (also somatostatin)
3) TSHR
4) CRH
5) DA/TRH (thryotrophin releasing hormone)

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3
Q

What is the difference between primary, secondary and tertiary endocrine gland disease? (3)

A

https://www.google.com/search?q=primary+secondary+tertiary+endocrine+disorders&source=lnms&tbm=isch&sa=X&ved=0ahUKEwje87HqqNrgAhUtUBUIHQNNB1YQ_AUIDigB&biw=1177&bih=603#imgrc=wQSYz4QW0mUOuM:

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4
Q

What is the term given to decreased secretion of all anterior pituitary hormones? (1)

A

Panhypopituitarism

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5
Q

Broadly speaking what can cause panhypopituitarism? (2)

A

Genetic - rare (congenital)

Acquired

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6
Q

Why is the genetic contribution to panhypopituitarism congenital rather than acquired? (3)

A
  • The mutations that lead to panhypopituitarism occur in TFs that are involved in development of cells of the anterior pituitary (adenohypophysis)
  • For example, it could be mutation in the PROP1 gene
  • Poorly developed cells in the anterior pituitary will not be able to release their hormones as effectively if at all
  • On an MRI will observe a hypoplastic adenohypophysis
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7
Q

How can one ‘acquire’ panhypopituitarism? (3)

A
  • Tumours e.g. craniopharyngiomas from the hypothalamus or adenomas developed from within the pituitary itself
  • Inflammatory - the pituitary gland and endocrine glands are generally susceptible to autoimmune attack
  • Peripartum infarction (as in the case of Sheehan’s syndrome)
  • Haemorrhage (as in the case of pituitary apoplexy)
  • Traumatic brain injury
  • Radiation
  • Infection
  • Infiltrative diseases e.g. neurosarcoidosis
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8
Q

What are the 3 forms of panhypopituitarism? (3)

A

1) Simmond’s disease
2) Sheehan’s syndrome
3) Pituitary apoplexy

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9
Q

What are the symptoms of Simmond’s disease? (3)

A
  • Depends on which hormones are missing (multiple or all may be missing)
  • Missing GH won’t have too much effect on adults
  • Missing LH/FSH = secondary hypogonadism (in females will get secondary amenorrhoea and in males will get erectile dysfunction. In both may have loss of libido)
  • Missing ATCH = secondary hypoadrenalism (inability to produce cortisol - fatigue)
  • Missing TSH = secondary hypothyroidism (lower metabolic rate - fatigue + weight gain )
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10
Q

What causes Sheehan’s syndrome? (3)

A
  • During pregnancy lactotrophs proliferate (hyperplasia) as have increased activity
  • Post-partum haemorrhage can lead to severe systemic hypotension in women because they lose so much blood
  • Blood loss can lead to reflex vasoconstriction. Vasoconstrictor spasm in hypophyseal arteries can lead to ischaemia of the adenohypophysis
  • Neurohypophysis largely unaffected
  • Ischaemia leads to death of cells (by necrosis)
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11
Q

What causes pituitary apoplexy? (4)

A
  • Pituitary apoplexy is caused by intra-pituitary haemorrhage or less commonly infarction
  • Ischaemia leads to death of cells within the adenohypophysis
  • This can be caused by a pituitary adenoma (symptomatically may present with double vision)
  • This can be precipitated by use of anticoagulants
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12
Q

How does Sheehan’s syndrome present? (3)

A
  • Prolactin deficiency means there will be a failure to lactate
  • Failure to resume menses (amenorrhea)
  • ACTH deficiency (and loss of cortisol) may lead to weight loss
  • TSH deficiency may lead to lethargy/fatigue
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13
Q

Why is basal plasma concentration of pituitary (or other hormones) not a great diagnostic tool? (1)

A

Interpretation is limited because the hypothalamus releases its hormones in a pulsatile fashion
This means the rest of the axis is subject to the same sort of pulsatile nature so a single measurement is useless - you don’t know where in the cycle the concentrations are

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14
Q

How can we biochemically diagnose hypopituitarism? (3)

A
  • Conduct a stimulation test
  • The gold standard technique is to induce hypoglycaemia using insulin
  • This triggers the release of ACTH (and also GH) to promote cortisol release to counteract insulin
  • For the other hormones just use the standard hypothalamic releasing hormone (for LH/FSH –> GnRH and for TSH –> TRH)
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15
Q

How can hypopituitarism be diagnosed? (2)

A
  • Biochemical diagnosis (stimulation tests)

- Radiological (MRI e.g. to see if there is atrophy of tissues)

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16
Q

With ACTH deficiency how would you treat the patient? (extra +1)

A

Administer hydrocortisone and then regularly check serum cortisol

17
Q

With prolactin deficiency how would you treat the patient? (extra +1)

A

You cannot replace prolactin. For men no significant effect. For women they can’t breast feed

18
Q

With TSH deficiency how would you treat the patient? (extra +1)

A

Administer thryoxine and check serum free T4

19
Q

With LH/FSH deficiency how would you treat the patient? (extra +2)

A

In men give testosterone and monitor serum testosterone/check for symptom improvement
In women give HRT (E2 + progestagen) and monitor symptom improvement/withdrawal bleeds

20
Q

What happens to adults and children with GH (somatotrophin) deficiency? (2)

A

Children: pituitary dwarfism
Adults: not that much (may have reduced sense of well-being/lower quality of life and show less muscle mass + more fat tissue + loss of bone mineral density)

21
Q

Draw the GH (somatotrophin) axis. (4)

A

See bottom of page 4

  • GHRH (1)
  • Somatostatin (SS) inhibitor effect (1)
  • Somatotrophin from adenohypophysis (acting on peripheral tissues + liver)
  • IGFI/IGF II from liver
22
Q

Other than GH deficiency what else can cause short stature? (4)

A
  • Malnutrition or malabsorption (e.g. coeliac’s)
  • Genetic diseases e.g. Down’s syndrome, Prader Willi, Turner’s
  • Emotional deprivation
  • A consequence of other systemic diseases like cystic fibrosis
  • Endocrine disorders like Cushing’s, hypothyroidism, poorly controlled T1DM
  • Skeletal dysplasias (achondroplasia/osteogenesis imperfecta)
23
Q

Pituitary dwarfism causes slow growth in children. What is pituitary dwarfism caused by? (1)

A

It is caused by not producing enough or any growth hormone (somatotrophin) due to disease of the adenohypophysis itself

24
Q

Larown dwarfism can cause slow growth in children. What is Laron dwarfism caused by? (1)

A

It is caused by a defect in the GH receptor so the individual does not respond to GH even if levels are sufficient

25
Q

Name 2 diseases of the GH axis which can lead to short stature.(2)

A

Pituitary dwarfism
Laron dwarfism
Prader-Willi syndrome

26
Q

How does Prader-Willi syndrome cause short stature? (1)

A

In PWS the hypothalamus of the individual does not sufficiently promote GH release so you get apparent GH deficiency

27
Q

How is the treatment for short stature caused by Prader-Willi syndrome different to the treatment of short stature caused by Laron dwarfism? (3)

A
  • In PWS can give GH and by-pass the hypothalamic dysfunction
  • In Laron dwarfism GH treatment would not work because it is the actual GH receptor that is the problem
  • In Laron dwarfism can give IGF-1 (a downstream signalling molecule of GH)
28
Q

How is short stature diagnosed? (1)

A

Based on projected growth curves, these are based on father and mother’s height

29
Q

What can cause GH deficiency in adults? (2)

A
  • Trauma
  • Pituitary tumour or pituitary surgery
  • Cranial radiotherapy
30
Q

How can GH deficiency in adults be diagnosed? (3)

A
  • Generally use biochemical testing: stimulation tests
  • Stimulate in a number of different ways e.g. GHRH + Arg (synergistic), glucagon, exercise (10 minute step climbing if appropriate)
  • Gold standard insulin induce hypoglycaemia
31
Q

What are the benefits of GH treatment in adults? (2)

A

Better psychological well being
Increased bone mineral density
Increased muscle mass
Less adiposity

32
Q

Does GH therapy increase risk of cancer?

A

No - does not seem to

33
Q

What disadvantages of GH therapy are there? (1)

A

EXPENSIVE. 42K/year of treatment

Endocrinology (27 decks)

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