Pituitary gland abnormalities (week 4) Flashcards

1
Q

What are the hormones secreted by anterior pituitary gland

A

Prolactin
ACTH
TSH
GH
LH and FSH

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2
Q

What are the hormones secreted by posterior pituitary gland

A

Oxytocin
ADH

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3
Q

Function of prolactin

A

stimulate breast milk production, breast tissue growth

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4
Q

Function of ADH (anti diuretic hormone)

A

Controls how much water is excreted into urine

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5
Q

Function of GH

A

growth and development

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6
Q

Function of ACTH

A

stimulates adrenal cortex to produce cortisol

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7
Q

Function of oxytocin

A

Stimulates uterine contraction during labour
Promotes breastfeeding

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8
Q

Pituitary pathologies can be

A

Hyperfunction / hypofunction

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9
Q

Hyperfunction of the the pituitary is caused by

A

Secreting adenomas

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10
Q

Adenomas can be (function, size)

A

Secreting / non-secreting
Micro/Macro

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11
Q

How may macro adenomas cause hypopituitarism

A

Due to large infarction of the pituitary gland tissue

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12
Q

Symptoms of non-secreting adenomas

A

Headaches
Impaired visual field

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13
Q

Investigation for non-secreting adenomas

A

MRI
Hormone tests to exclude other causes

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14
Q

Management for non-secreting adenomas

A

Surgery
Radiotherapy

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15
Q

Types of secreting adenomas

A

Prolactinoma
GH secreting adenoma
ACTH secreting adenoma
TSH secreting adenoma (very rare)

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16
Q

What does TSH secreting adenoma cause

A

Secondary hyperthyroidism (very rare)

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17
Q

Most common secreting pituitary adenomas

A

Prolactinoma

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18
Q

Symptoms of hyperprolactinaemia due to prolactinoma

A

females - oligomenorrhea/amenorrhea, infertility, vaginal dryness, galactorrhea
Males- erectile dysfunciton, gynaecomastia, reduced facial hair
Both- headaches, low sex drive, impaired visual fields

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19
Q

Investigations for prolactinoma

A

Serum prolactin level
Serum level of other hormones
MRI

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20
Q

Results of investigations for prolactinoma

A

Raised prolactin
Decreased level of other hormones
Lesions / tumour seen on MRI

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21
Q

Management for small prolactinoma

A

Dopamine agonists
Hormone therapy - oestrogen

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22
Q

Management for larger prolactinoma

A

Surgery

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23
Q

What dopamine agonists are used for prolactinoma

A

cabergoline

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24
Q

Side effects of cabergoline (dopamine agonists)

A

Nausea / vomiting
low mood
obsessive compulsive behaviour

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25
Q

If a patient with small prolactinoma has been taking dopamine agonists for over a year and has not experienced any symptoms, what should you do? - continue the treatment ?

A

Stop dopamine agonist because hyperprolactinaemia is likely to resolve
Start again if hyperprolactinaemia persist

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26
Q

Hormone replacement therapy is used in prolactinoma if

A

fertility and galactorrhea are not issues

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27
Q

Types of causes of hyperprolactinaemia

A

Physiological
Pathological - prolactinoma

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28
Q

Physiological causes of hyperprolactinaemia

A

Pregnancy
Breastfeeding
Anxiety
Use of dopamine antagonists
Use of anti-psychotics

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29
Q

Examples of dopamine antagonists

A

Risperidone
Metoclopramide

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30
Q

What is SIADH (syndrome of inappropriate ADH production)

A

Excessive ADH production due to pathology in posterior pituitary / ectopic ADH

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31
Q

What damage to the brain can cause SIADH

A

subarachnoid haemorrhage (bleeding on the surface of the brain)

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32
Q

What are the non-pituitary cause of SIADH

A

Small cell lung cancer
Lymphoma
Infections
Pneumothorax
Cystic fibrosis
Chemotherapy

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33
Q

What is a common PMH in patients with SIADH

A

Lung cancer (small cell lung cancer)

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34
Q

Symptoms of SIADH is caused by

A

hyponatraemia

35
Q

Symptoms of SIADH

A

Muscle cramping
Nausea
Vomiting
Confusion / reduced GCS level
Seizures

36
Q

Investigations for SIADH

A

Urea and electrolytes
Plasma osmolarity
Urine osmolarity
Urine sodium
MRI

37
Q

Results for investigations for SIADH

A

U&E - hyponatraemia
Plasma osmolarity - reduced
Urine osmolarity - raised
Urine sodium - raised

38
Q

Why is there hyponatraemia in SIADH

A

Because excessive ADH causes excessive retaining of water = blood becomes very diluted = hyponatraemia and reduced plasma osmolarity

39
Q

Why is urine osmolarity raised in SIADH

A

Because water is retained in the body and not passed out into the urine so urine becomes very concentrated

40
Q

Management of mild SIADH

A

Fluid restriction
Treat the underlying cause via surgery

41
Q

Management of moderate-severe SIADH

A

Rapid correction of hyponatraemia by
1. Hypertonic saline
2. Loop diuretics
3. Democlocycline (tetracycline)
4. Vasopressin antagonist

42
Q

Mechanism of democlocycline

A

Blocks ADH and induces partial nephrogenic diabetes insipidus

43
Q

What is panhypopituitarism

A

reduction in all hormones produced by the pituitary gland

44
Q

What causes panhypopituitarism

A

Surgery / radiotherapy
Haemorrhage, infarction - Sheehan’s
TB meningitis
Sarcoidosis

45
Q

What is Sheehan’s syndrome

A

Maternal hypopituitarism due to excessive bleeding during labour

46
Q

Symptoms of panhypopituitarism

A

hypothyroidism - MOMS SO TIRED
prolactin deficiency - oligo/amenorrhea, infertility, sexual dysfunction, breast atrophy, hypogonadism
Adrenal deficiency
GH deficiency - obesity, muscle weakness, reduced exercise tolerance
ADH deficiency (diabetes insipidus)

47
Q

Types of ADH deficiency

A

Cranial diabetes insipidus
Nephrogenic diabetes insipidus

48
Q

ADH deficiency (diabetes insipidus) can be due to

A
  1. ADH production deficiency = cranial diabetes insipidus
  2. Kidneys become ADH resistant i.e. they stop responding to ADH = nephrogenic diabetes insipidus
49
Q

What chemical can cause nephrogenic diabetes insipidus

A

Lithium toxicity

50
Q

Symptoms of ADH deficiency

A

Polyuria
Polydipsia
Thirst
Lethargy
Confusion/ reduced GCS
Seizures

51
Q

Investigations for ADH deficiency

A

U&E
Plasma osmolarity
24 hour urine collection - urine sodium and urine osmolarity
Fluid deprivation test

52
Q

Results of investigations that suggests ADH

A

U&E - hypernatraemia
Plasma osmolarity - raised
Urine sodium - low
Urine osmolarity - low
Fluid deprivation test - urine becomes concentrated

53
Q

Describe the fluid deprivation test

A

Deprive patients from fluid for a certain amount of time
Then administer desmopressin (synthetic ADH)
If urine becomes concentrated = ADH deficiency

54
Q

How does ADH deficiency cause hypernatraemia and raised plasma osmolarity

A

Because more water is passed out into the urine making the blood very concentrated and urine very diluted

55
Q

Treatment for ADH deficiency

A

Desmopressin

56
Q

What is phaeochromocytoma

A

Catecholamine-releasing tumour arising from the adrenal gland

57
Q

Where is phaeochromocytomas derived from

A

Chromaffin cells of adrenal medulla

58
Q

Are phaeochromocytomas malignant

A

Only 10% are and metastasise to elsewhere

59
Q

Apart from the adrenal medulla, do catecholamine releasing tumours appear at other sites

A

Yes but rare, sympathetic neurone
= paraganglioma

60
Q

Most common association with phaeochromocytoma

A

Persistent hypertension

61
Q

Phaeochromocytomas mainly occur in which age group

A

30-50 years old

62
Q

Symptoms of phaechromocytoma

A

Hypertension (can be episodic)
Fatigue
Sweating
Palpitations
Tremor
Weight loss
Anxiety
Postural hypotension
Hypertensive retinopathy

63
Q

Symptoms of phaeochromocytomas can be exacerbated by

A

Stress
Exercise
Surgery
Opiates
Beta Blockers

64
Q

Investigations for phaeochromocytoma

A
  1. Plasma metanephrine
  2. Urine metanephrine
  3. Adrenal imaging
  4. CT chest, abdomen, pelvis
65
Q

What is metanephrine

A

Substance released when catecholamines are broken down

66
Q

Management for phaeochromocytomas

A
  1. Alpha blockade first then Beta blockade
  2. surgery
67
Q

Which one should be used first, alpha blockade or beta blockade

A

alpha blockade

68
Q

Why should we use alpha and beta blockades before surgery for phaeochromocytoma

A

To increase blood volume and prevent hypertensive crisis

69
Q

Example of an alpha blockade

A

Phenoxybenzamine

70
Q

What is MEN syndrome

A

Multiple endocrine neoplasia; the formation of multiple hormone secreting tumours at multiple endocrine sites

71
Q

What causes MEN syndrome

A

Mutation in tumour suppression gene

72
Q

Inheritance pattern of MEN syndrome

A

Autosomal dominant

73
Q

Types of MEN syndrome

A

MEN 1
MEN 2a
MEN 2b

74
Q

Conditions associated with MEN 1 (the P syndrome)

A
  1. Pituitary adenoma (esp prolactinoma)
  2. Parathyroid gland hyperplasia
  3. Pancreatic tumours
75
Q

What are the pancreatic tumours that can present in MEN 1

A

Insulinoma
Gastrinoma

76
Q

What type of pituitary adenoma is the most common in MEN 1

A

Prolactinoma (acromegaly second)

77
Q

Describe the hormone level changes due to parathyroid gland hyperplasia

A

Serum Ca2+ elevated
Serum PTH elevated
Urine calcium:creatinine elevated

78
Q

What symptoms are caused by hypercalcaemia (Stones, Bones, Groans, Moans)

A

Renal calculi
Abdominal pain, nausea, vomiting
Psychosis
Lethargy
Depression
Painful bones
Osteoporosis
Fragility fractures
Hypertension

79
Q

Investigations for MEN 1

A

Genetic test
Hormone level (Ca2+, PTH, prolactin, urine Ca:creatinine)
Screen asymptomatic family members

80
Q

What are the conditions associated to MEN 2a

A
  1. Parathyroid hyperplasia
  2. Medullary thyroid carcinoma
  3. Phaeochromocytomas
81
Q

What are the conditions associated to MEN 2b

A
  1. Marfanoid
  2. Neuroma
  3. Medullary thyroid carcinoma
  4. Phaeochromocytoma
82
Q

Investigations for MEN 2

A

Genetic test
For phaeochromocytoma -plasma and urine metanephrine
For medullary thyroid carcinoma - calcitonin level and fine needle aspiration of the tumour
For parathyroid hyperplasia

83
Q

Management for MEN syndromes

A

Surgery