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Year 2 - ENDO > 1 - Hyposecretion of anterior pituitary hormones > Flashcards

1 - Hyposecretion of anterior pituitary hormones Flashcards

1
Q

What are primary and secondary endocrine diseases?

A

primary - problem with the endocrine gland/hormone released

secondary - problem with the pituitary gland/(stimulating) hormone released

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2
Q

Define hypopituitarism and panhypopituitarism

A

Decreased production of ALL anterior pituitary hormones (PANhypopituitarism) or of specific hormones

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3
Q

Broadly speaking, what can panhypopituitarism be caused by?

A 
Most likely to be acquired
Congenital defects (rare)
Gene mutations (more rare)
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4
Q

Give some causes of panhypopituitarism?

A
  • tumours - craniopharyngiomas, adenomas, metastases and cysts
  • radiation (GH is the most vulnerable and TSH is resistant)
  • infection - meningitis
  • traumatic brain injury
  • infiltrative disease (infiltrates the pituitary stalk) e.g. sarcoidosis
  • inflammatory - hypophysitis
  • pituitary apoplexy
  • post-partum infarction (Sheehan’s syndrome)
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5
Q

In what order does loss of pituitary secretion occur?

A 
Gonadotrophins 
GH
Thyrotrophin
Corticotrophin
Prolactin
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6
Q

What are the symptoms of someone who has developed panhypopituitarism through gene mutation of the PROP1 gene?

A
  • deficient in GH and at least 1 other anterior pituitary hormone
  • short stature
  • hypoplastic pituitary on MRI
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7
Q

What are three main types of panhypopituitarism? Briefly describe what they are

A
  • > Simmond’s Disease - panhypopituitarism
  • > Sheehan’s Syndrome - postpartum hypopituitarism secondary to hypotension/postpartum haemorrhage
  • > Pituitary Apoplexy - intra-pituitary infarction of haemorrhage
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8
Q

Describe the onset of Simmond’s disease and state some of its causes

A

onset is insidious

Can be caused by:
•	Infiltrative diseases 
•	Craniopharyngioma
•	Cranial injury
•	Pituitary adenomas 
•	Following surgery
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9
Q

What are the symptoms of Simmond’s disease?

A

(mainly due to loss of adrenal, gonadal and thyroid function)
• Impotence - GnRH
• Loss of libido - GnRH
• Secondary amenorrhoea or oligomenorrhoea - GnRH
• Fatigue - ACTH/TSH

NOTE: deficiency of GH has less of an impact in adulthood, because you have fully grown

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10
Q

State the cause of Sheehan’s syndrome

A

in pregnancy, lactotrophs become very enlarged (high prolactin) and the pituitary becomes very large. The anterior pituitary is hanging by a very thin stalk. During delivery women have a large postpartum haemorrhage., and hence the pituitary will become deprived of a decent blood supply.
Ischaemia and necrosis of the pituitary.

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11
Q

How does Sheehan’s syndrome present?

A
  • failure of lactation (no prolactin)
  • lethargy/anorexia/weight loss - deficiency of TSH/ACTH/GH
  • failure to resume menses post delivery
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12
Q

What is pituitary apoplexy? Describe its onset.

A

Similar to Sheehan’s syndrome but isn’t specific to women
It is caused by intra-pituitary infarction or haemorrhage (in an already pre-existing adenoma (common)
This also has a RAPID presentation

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13
Q

What are the symptoms of pituitary apoplexy?

A
  • visual defect field (compressed optic chiasm) - BITEMPORAL HERMIANOPIA
  • severe, sudden onset headache
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14
Q

How can you test a person to check that their producing a hormone at a normal level?

A

STIMULATION/PROVOCATION TEST - administration of various releasing hormones

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15
Q

Why is a single measurement of most hypothalamic hormones not useful?

A

Most hypothalamic hormones tend to be released in pulses

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16
Q

How are the releasing hormones administered in stimulation/provocation tests?

A

intravenously

17
Q

Specifically, how are each of the anterior pituitary hormones stimulated and measure in a stimulation/provocation test?

A

ACTH + GH - ‘street hormones’ —–> (make the person hypoglycaemic) inject insulin and measure cortisol and GH
TSH —–> give TRH and measure TSH
FSH/LH —–> give GnRH and measure FSH/LH

(if you want to have a lot at the pituitary, you can do a pituitary MRI)

18
Q

What is the name given to the secondary endocrine gland failure that results from a lack of corticotrophin release from the pituitary?

A

Hypoadrenocorticalism

19
Q

What are the effects of a lack of somatotrophin in children and in adults?

A

Children – stunted growth (pituitary dwarfism)

Adults – loss of GH effects are uncertain

20
Q
  1. For each of the following anterior pituitary hormone deficiencies, state the replacement used and the parameter that is monitored during treatment:
    a. ACTH
    b. TSH
    c. Women – LH/FSH
    d. Men – LH/FSH
    e. GH
A 
a.	ACTH
Give hydrocortisone
Monitor serum cortisol
b.	TSH
Give thyroxine
Monitor serum T4
c.	Women – LH/FSH
Give E2 plus progestagen
To check - Symptom improvement, withdrawal bleeds 
d.	Men – LH/FSH
Give testosterone
Monitor libido and serum testosterone 
e.	GH
Give GH 
Monitor IGF I
21
Q

What are the effects of a lack of somatotrophin in children and in adults?

A

Children – stunted growth (pituitary dwarfism)

Adults – loss of GH effects are uncertain

22
Q

Give some causes of short stature

A 
Genetic:
- Down’s syndrome
- Turner’s syndrome
- Prader-Willi syndrome
Emotional Deprivation
Systemic disease
- Cystic Fibrosis
- Rheumatoid arthritis
Malnutrition
Malabsorption
- Coeliac disease
Endocrine Disorders
- Cushing’s syndrome
- Hypothyroidism
- GH deficiency
- poorly controlled T1DM
Skeletal dysplasias
- Achondroplasia
- osteogenesis imperfecta
23
Q

Describe the growth axis

A
  • hypothalamus stimulates the release of GHRH (and inhibitory somatostatin)
  • GH is released from the anterior pituitary
  • GH acts as a hormone, but also stimulates the liver to produce IGF I, which mediates growth effects
24
Q

Briefly describe the causes of short stature in children

A

Prader-Willi syndrome
Pituitary dwarfism
Laron Dwarfism

25
Q

How does Prader-Willi syndrome lead to short stature in children?

A

GH deficiency secondary to hypothalamic dysfunction
(defects are from the hypothalamus)

(tertiary hypopituitarism)

26
Q

How does pituitary dwarfism syndrome lead to short stature in children?

A

defects are from the anterior pituitary

secondary hypopituitarism

27
Q

How does baron dwarfism lead to short stature in children?

How can this be treated?

A

Mutation in GH receptor - GH receptor defect

Short stature because because IGF I levels are low (because somatotrophin isn’t having its effect)

IGF-1 treatment in childhood can increase height

28
Q

How is short statues diagnosed in children?

A

using the mid-parental height

  • a predicted adult height is produced based on the average of the mothers and fathers height
  • it is important to follow the progression of height across the centiles - a drop of more than 2 centiles is flagged
29
Q

What are the causes of acquired GH deficiency in adults?

A

TRAUMA
PITUITARY TUMOUR
PITUITARY SURGERY
CRANIAL RADIOTHERAPY

30
Q

What is the gold standard method of testing the ability of the pituitary to release growth hormone?

A

Insulin-induced hypoglycaemia
Hypoglycaemia is a potent stimulus for growth hormone release

Plasma GH is measured at specific time-points (before and after)

31
Q

State three alternative triggers to increase GH release to insulin-induced hypoglycaemia in the provocation test?

A

Arginine
Glucagon
Exercise

32
Q

Describe how the insulin-induced hypoglycaemia test is used to test GH secretion.

A

In a normal subject, the insulin-induced hypoglycaemia will give a massive rise in GH secretion
If you have a partial deficiency of GH then your response will be reduced

33
Q

How is GH deficiency diagnosed in adults?

A

Lack of response to GH stimulation test (e.g. insulin-induced hypoglycaemia)
Low plasma IGF I
Low plasma IGF-BP3

34
Q

What is given in GH therapy and how is it administered?

A

Preparation:
Human recombinant GH (SOMATOTROPIN)

Administration:
Daily, subcutaneous injection
Monitor clinical response & adjust dose to IGF-1

35
Q

What are the signs and symptoms of GH deficiency in adults?

A
  • Reduced lean mass, increased adiposity, increased waist:hip ratio
  • Reduced muscle strength & bulk -> reduced exercise performance
  • Decreased plasma HDL-cholesterol & raised LDL-cholesterol
  • Impaired ‘psychological well being’ and reduced quality of life
36
Q

What are the potential benefits of GH therapy in adults?

A
  • Improved body composition
  • Improved muscle strength and exercise capacity
  • Normalisation of HDL-LDL
  • Increased bone mineral content
  • Improved psychological and mental wellbeing and quality of life
37
Q

What are the potential risks of GH therapy in adults?

A
  • Increased susceptibility to cancer (no evidence)
  • Expensive
  • Increased risk of cardiovascular accidents
  • Increased growth of soft tissue e.g. cardiomegaly
38
Q

which adenohypophyisis hormones are ‘stress’ hormones?

A

growth hormones and ACTH

Year 2 - ENDO (20 decks)

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