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Endocrine- Pituitary > Pituitary Hypofunction > Flashcards

Flashcards in Pituitary Hypofunction Deck (58)
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1
Q

Is it common for pituitary hypo function to affect specific hormones?

A

No

2
Q

What is panhypopituitarism?

A

All the pituitary hormones are under secreted

3
Q

What 5 things does panhypopituitarism result in?

A
  • Hypothyroidism
  • Hypoadrenalism
  • Growth failure
  • Hypogonadism
  • Diabetes Insipidus
4
Q

Name some causes of panhypopituitarism?

A
Tumours or metastases
Infections
Iatrogenic
Granulomatous disease
Vascular disease
Trauma
Autoimmune
5
Q

What is Sheehan’s Syndrome?

A

This occurs during pregnancy when the pituitary gland enlarges and causes ischaemia of the gland

6
Q

What are some signs and symptoms of hypogonadism?

A

Menstrual irregularities
Infertility
Impotence
Gynaecomastia

7
Q

What are some general features of panhypopituitarism?

A

Abdominal obesity
Loss of facial, axillary and pubic hair
Dry skin and hair

8
Q

What therapy is always given first in panhypopituitarism?

A

Hydrocortisone 10-25mg/day

9
Q

Apart from hydrocortisone, what other hormone replacement therapies should be given in panhypopituitarism?

A
  • Thyroxine 100-150mcg/day
  • ADH desmospray nasal or tablets
  • Nightly SC GH
  • Sex hormone replacement
10
Q

What is the sex hormone replacement therapy in females?

A

HRT/progesterone/oestrogen pill

11
Q

What is the sex hormone replacement therapy in males?

A

Testosterone

12
Q

What is the relationship between testosterone therapy and prostate cancer?

A

Testosterone therapy does not cause prostate cancer however it can enlarge the prostate and cause growth of a cancer if it is already there

13
Q

What should always be done before starting testosterone therapy?

A

Screen for prostate cancer

14
Q

What are two other side effects of testosterone therapy and how are they monitored?

A

Polycythaemia- monitor FBC

Hepatitis- monitor FBC

15
Q

What is the only type of testosterone therapy that can causes hepatitis?

A

Oral

16
Q

What are 4 effects of GH when given to adults?

A
  • Improves wellbeing and quality of life
  • Decreases abdominal fat
  • Improves CV function
  • Decreases cholesterol
17
Q

What hormone mainly controls thirst and water regulation?

A

ADH

18
Q

Where is ADH synthesised and where is it released?

A

Synthesised- hypothalamus

Released- posterior pituitary

19
Q

Where is the predominant site of the action of ADH?

A

Kidneys

20
Q

What receptors does ADH stimulate in the kidneys?

A

V2

21
Q

What does ADH stimulating the V2 receptor do?

A

Allows the collecting ducts to become permeable to water via the migration of AQP2 channels, thus allowing reabsorption of fluid

22
Q

What is the overall result of ADH secretion?

A

Decreased diuresis and overall retention of water

23
Q

What other receptors does ADH target at high concentrations?

A

V1 in vascular tissues

24
Q

What effect does ADH have when it binds with V1 receptors?

A

Vasoconstriction

25
Q

What are changes in plasma osmolality sensed by?

A

Osmoreceptors in the anterior hypothalamus

26
Q

At what osmolality is ADH secretion suppressed?

A

< 280

27
Q

If plasma osmolality increases, what happens to the secretion of ADH?

A

Increases

28
Q

What is nephrogenic DI?

A

The renal tubules are resistant to ADH (receptor abnormality)

29
Q

What can cause nephrogenic DI?

A

Lithium, hypokalaemia, hypercalcaemia, genetics

30
Q

What is cranial DI?

A

A problem secreting ADH from the posterior pituitary as a result of hypothalamic disease

31
Q

What can cause cranial DI?

A

Tumours and metastases, granulomatous disease, trauma

32
Q

How do you calculate serum osmolality?

A

2Na + 2K + glucose + urea

33
Q

What is the normal range for serum osmolality?

A

285-295

34
Q

What are the main clinical features of DI?

A

Polyuria and polydipsia

35
Q

What is the most common cause of DI?

A

Hypothalamic-pituitary surgery

36
Q

What happens when DI occurs following hypothalamic-pituitary surgery?

A

It is transient and usually remits after a few days-weeks

37
Q

What is familial isolated vasopressin deficiency?

A

Causes DI from a young age and is dominantly inherited

38
Q

What type of disease is Wolfram Syndrome?

A

Rare, autosomal recessive

39
Q

What diseases does Wolfram Syndrome comprise?

A

DI, DM, optic atrophy, deafness

40
Q

Where is the mutation that causes Wolfram Syndrome?

A

WFS1 gene on chromosome 4

41
Q

What may an MRI show in Wolfram Syndrome?

A

An absent or poorly developed posterior pituitary

42
Q

What will plasma and urine osmolality be in DI?

A

Plasma- high

Urine- low

43
Q

What will the sodium concentration be in DI?

A

High

44
Q

What will happen when there is fluid deprivation in DI?

A

The urine still will not concentrate

45
Q

What is the main test for DI?

A

Water deprivation test

46
Q

What would be a normal response following a water deprivation test?

A

Serum osmolality remains within the normal range

Urine osmolality > 600

47
Q

What would be a DI response following a water deprivation test?

A

Serum osmolality rises above normal without adequate concentration of urine osmolality (serum > 300, urine < 600)

48
Q

What type of DI is present if desmopressin still will not concentrate the urine?

A

Nephrogenic

49
Q

What type of DI is present if desmopressin causes the urine osmolality to increase by 50%?

A

Cranial

50
Q

What treatment options are there for DI?

A
  • Nasal desmospray 10-60mcg/day
  • Oral desmopressin tablets 100-1000mcg/day
  • IM desmopressin injection 1-2mcg/day
51
Q

What is syndrome of inappropriate ADH secretion?

A

Ectopic production of ADH

52
Q

Name some causes of inappropriate ADH secretion?

A

Carcinoid tumours, pulmonary lesions, CNS damage, alcohol withdrawal, porphyria, drugs

53
Q

What does inappropriate ADH secretion cause?

A

Retention of water and hyponatraemia

54
Q

What is the presentation of inappropriate ADH secretion?

A

Usually vague, with confusion, nausea, irritability and later on fits and coma

55
Q

What is the main treatment of inappropriate ADH secretion?

A

Treat the underlying cause

56
Q

What is the most effective symptom relief for ectopic ADH production if patients can tolerate it?

A

Fluid restriction to 500-1000ml per day

57
Q

What drug is used for ectopic ADH production if fluid restriction isn’t tolerated?

A

Demeclocycline

58
Q

What drug can be used in the long run of inappropriate ADH secretion?

A

Vasopressin V2 antagonists