Hyposecretion of anterior pituitary hormones Flashcards Preview

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Flashcards in Hyposecretion of anterior pituitary hormones Deck (45)
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1
Q

What is primary endocrine gland disease?

A

When it caused by disorder of the endocrine gland

2
Q

What is secondary endocrine gland disease?

A

When it is caused by disorder of the anterior pituitary

3
Q

What is tertiary endocrine gland disease?

A

When it is caused by disorder of the hypothalamus

4
Q

What is panhypopituitarism?

A

Decreased production of all anterior pituitary hormones

5
Q

How can panhypopituitarism be acquired? (6)

A
Tumours- hypothalamic and pituitary
Radiation- damage
Infection- meningitis
Traumatic brain injury
Infiltrative disease
Inflammatory
6
Q

How else can panhypopituitarism be caused?

A

Congenital (rare) or mutations (very rare)

7
Q

How does panhypopituitarism usually develop?

A

In an adult with progressive loss of pituitary secretion>

8
Q

What is the normal order of pituitary secretion loss?

A

Gonadotrophins
GH
Thyrotrophin
Corticotrophin

9
Q

What are the three main types of panhypopituitarism?

A

Simmond’s disease
Sheehan’s syndrome
Pituitary apoplexy

10
Q

What is the onset of Simmond’s like?

A

Insidious- very slow

11
Q

What are the causes of Simmond’s? (5)

A
Infiltrative processes
Pituitary adenomas
Craniopharyngiomas
Cranial injury
Post surgery
12
Q

What are the symptoms of Simmond’s mainly due to?

A

Loss of thyroidal, gonadal and adrenal function

13
Q

What are the symptoms of Simmond’s?

A
Secondary amenorrhoea
Impotence
Loss of libido
Tiredness
Waxy skin
Loss of body hair
Hypotension
14
Q

What is different about Sheehan’s compared to the other two?

A

It is specific to women

15
Q

How does Sheehan’s develop?

A

Develops acutely following postpartum haemorrhage resulting in pituitary infarction

16
Q

How does the postpartum haemorrhage lead to pituitary infarction?

A

The blood loss results in vasoconstrictor spasm of the hypophysial arteries and this leads to ischaemia and necrosis of the pituitary

17
Q

How does Sheehans and pituitary apoplexy compare?

A

Very similar but pituitary apoplexy is in men and women and just due to normal haemorrhages

18
Q

How do you diagnose hypopituitarism?

A

You can’t measure hypothalamic hormones so you measure basal values of the plasma for pituitary or target endocrine gland hormones

19
Q

Why will a single measurement not suffice?

A

Hypothalamic hormones are released in pulses

20
Q

What test can you use to find out if a person is producing hormones at a normal level?

A

Stimulation test

21
Q

What does a lack of somatotrophin cause in children and adults?

A

Pituitary dwarfism in children

Effects uncertain in adults

22
Q

What are other causes of short stature in children? (6)

A
Genetic- Down's, Turner's, Prader Willi
Malnutrition
Emotional deprivation
Systemic disease
Malabsorption
Endocrine disorders- Cushing's, hypothyroidism, GH deficiency
23
Q

What are the acquired causes of GH deficiency in children? (6)

A
Tumours of the hypothalamus or pituitary
Other intercranial tumours nearby (optic nerve glioma)
Irradiation
Head injury
Infection or inflammation
Severe psychosocial deprivation
24
Q

What are the genetic causes of GH deficiency in children?

A

Congenital (rare) - Deficiency of hypothalamic GHRH
Mutations of the GH gene (very rare)
Developmental abnormalities

25
Q

What controls GH at a hypothalamic level?

A

GHRH and somatostatin

26
Q

What are most endocrine-related causes of short stature due to?

A

Decreased production of GHRH

27
Q

What does GH stimulate the production of in the liver?

A

IGF-1 (insulin like growth factor) (liver is main source but is produced in many places)

28
Q

What does IGF-1 do?

A

Mediate growth effects

29
Q

What is laron dwarfism due to?

A

GH receptor defect

30
Q

Explain how GH receptor defect leads to Laron dwarfism?

A

As a result IGF-1 levels are low as somatotrophin isn’t having an effect

31
Q

What is the main presentation of Kallmann’s syndrome?

A

Hypogonadism and anosmia

32
Q

What is Kallmann’s caused by?

A

Genetic defect where the neurones in the embryo that will go on to produce GnRH are unable to migrate to the hypothalamus so their hypothalamus lacks GnRH neurones

33
Q

What other condition leads to hypogonadism and is a hypothalamic defect?

A

Prader Willi

34
Q

What is the standard way of testing the ability of the pituitary to produce GH?

A

Stimulate GH production by inducing hypoglycaemia (The gold standard is insulin induced hypoglycaemia)

35
Q

What is the main aim of pituitary deficiency treatment?

A

Restore homeostasis by replacing missing hormones

36
Q

What does growth hormone therapy lead to in children?

A

Acceleration of linear growth

Decreased body fat

37
Q

Which children respond better to growth hormone therapy?

A

Young and obese

38
Q

What is a common problem with GH therapy?

A

They develop resistance (antibodies)

39
Q

How is growth hormone therapy administered?

A

Subcutaneous or intramuscular

40
Q

When is GH administered?

A

Daily- In the afternoon as levels are normally high at night anyway

41
Q

What is the half life of GH like?

A

Short- 20 mins

42
Q

What does GH work on hence what is its action duration like?

A

Protein synthesis so long

43
Q

What are the adverse effects of GH?

A

Lipoatrophy at site of injection
Intracranial hypertension- headaches
Increased risk of cancer

44
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 and bulk
Decreased HDL and increased LDL
Impaired psychological wellbeing
45
Q

What are the 4 ways of diagnosing GH deficiency in adults?

A

Lack of response to GH stimulation test
GHRH and Arginine
Low plasma IGF-1
Low plasma IGF-BP3