Hyposecretion of Anterior Pituitary Hormones Flashcards

1
Q

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

A

Primary – problem with the endocrine gland/hormone released
Secondary – problem with the pituitary gland/hormone released
Tertiary – problem with the hypothalamus

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2
Q

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

A

Panhypopituitarism

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3
Q

What are three main types of panhypopituitarism?

A

Simmond’s Disease
Sheehan’s Syndrome
Pituitary Apoplexy

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4
Q

Describe the onset of Simmond’s disease

A

Very slow onset

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5
Q

State the cause of Sheehan’s syndrome

A

This is specific to WOMEN
It is caused by vasoconstrictor spasm of hypophysial arteries as a result of post-partum haemorrhage
This spasm causes pituitary infarction

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6
Q

What is pituitary apoplexy? Describe its onset.

A

This is similar to Sheehan’s syndrome but isn’t specific to women
It is caused by intra-pituitary infarction or haemorrhage potentially from a tumour This also has a RAPID presentation

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7
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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8
Q

What type of test do you do to test if someone is producing a hormone?

A

Stimulation/provocation test

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9
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

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10
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

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11
Q

State some causes of short stature.

A

Genetic
Malnutrition
Emotional deprivation
Endocrine disorders

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12
Q

State some acquired causes of GH deficiency in children.

A
Tumours of the hypothalamus and pituitary Other intracranial tumours nearby (e.g. optic nerve glioma)
Irradiation 
Head injury  
Infection or inflammation  
Severe psychosocial deprivation
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13
Q

As well as being its own hormone, GH stimulates the production of other hormones. State one important hormone that is stimulated by GH, its side of production and its effects.

A

IGF I = insulin-like growth factor I
It is produced in the LIVER
It mediates growth effects

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14
Q

What type of dwarfism is caused by a GH receptor defect?

A

Laron Dwarfism

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15
Q

Describe the IGF I levels in people with this Laron dwarfism.

A

LOW IGF I

Because functioning GH receptors are necessary for GH to stimulate the production of IGF I

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16
Q

Why are the Pygmies in Africa naturally short?

A

Their IGF I doesn’t function properly

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17
Q

Using GnRH as an example. State one example of tertiary hypopituitarism

A

Prader-Willi Syndrome

18
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

19
Q

State three other triggers for an increase in GH release.

A

Arginine
Glucagon
Exercise

20
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

21
Q

State some of the effects of growth hormone therapy in children and what groups of children respond better

A

Increased linear growth
Decease in body fat
Younger children respond better
Obese children respond better

22
Q

How is the human recombinant GH used in GH therapy administered and how frequently must it be given?

A

Subcutaneous or Intramuscular

It is given daily or 4/5 times a week

23
Q

Describe the absorption, metabolism and duration of action of the GH therapy

A

It has a maximal plasma concentration after 4-6 hours
Metabolism – renal and hepatic with a short half-life (20 mins)
Duration of action – it works on protein synthesis so it’s duration of action is going to be quite long.
IGF I levels peak after around 20 hours

24
Q

State some adverse effects of GH therapy.

A

GH is also a cell stimulation hormone so there is an increased risk of tumours

25
State some signs and symptoms of GH deficiency in adults.
``` Decreased muscle mass Increased adiposity Increased waist: hip ratio Decrease HDL and increased LDL Reduced muscle strength and bulk Impaired psychological wellbeing and quality of life ```
26
How can you diagnose GH deficiency in adults?
Lack of response to GH stimulation test
27
What are the potential benefits of GH therapy in adults?
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
28
What are the potential risks of GH therapy in adults?
Increased risk of cardiovascular accidents Cardiomegaly Increased susceptibility to cancer
29
Causes of symmonds disease
Infiltrative diseases Craniopharyngioma Cranial injury Following surgery
30
Symptoms of symmonds disease
Impotence Loss of libido Hypotension Tirednesss Secondary amenorrhoea or oligomenorrhoea Loss of body hair Waxy skin
31
Genetic causes of GH deficiency in children
Laron dwarfism Syndromes- prader willi, downs and turners Achondroplasia
32
How is prader wili syndrome an example of tertiary hypopituitary disease
Hypogonadism is one of the aspects of this disorder and the problem is at the level of the hypothalamus
33
Replacement APPH used for ACTH and what is monitored
Hydrocortisone | 9am cortisol
34
Replacement APPH used for TSH and what is monitored
Levothyroxine | Monitor T4
35
Replacement APPH used for LH and FSH in women and what is monitored
HRT | Symptom improvement such as libido
36
Replacement APPH used for LH/FSH in men and what is monitored
Testosterone undecanoate | Monitor libido and serum testosterone
37
Replacement APPH used for GH and what is monitored
Give GH | Monitor IGF 1
38
Nature of release of ACTH and GH
Pulsatile
39
Nature of release of LH and FSH
Cyclical
40
Signs of pituiraty apoplexy
Severe headache Ptosis Visual field defect
41
Signs of sheehans syndrome
Lethargy Anorexia Failure of lactation Failure to resume menses post delivery
42
What happens to pituitary during pregnancy
Enlarges due to lactotroph hyperplasia