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MEH > Pituitary Disorders incl DI > Flashcards

Pituitary Disorders incl DI Flashcards

1
Q

Clinical presentation of pituitary tumours

A
  • pressure on surrounding structures > visual loss, headache, vomiting, nausea
  • abnormality on pituitary function > hyper/hypo secretion
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2
Q

Reason for visual field loss in pituitary tumours

A

Upwards (superior) growth of pituitary tumour
Pressure on the optic chiasm
bitemporal haemianopia

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3
Q

Consequences of sideways (lateral) growth of pituitary tumour

A

Pain
Double vision

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4
Q

Consequences of upwards (superior) growth of pituitary tumour

A

Visual field loss due to pressure on optic chiasm causing bitemporal hemianopia

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5
Q

what is hypopituitarism?
What is it commonly caused by?

A
  • diminished hormone secretion by the anterior pituitary gland (+ADH)
  • pituitary adenoma
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6
Q

Changes in hormone levels in hypopituitarism

A

all go down apart from prolactin increase
due to disinhibition hyperprolactinaemia

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7
Q

What is the best imaging modality for pituitary gland?

A

MRI

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8
Q

what does Growth hormone deficiency cause?

A

Short stature in children - pituitary dwarfism
Reduced quality of life in adults

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9
Q

what does Gonadotropin (LH + FSH) deficiency cause?

A
  • delayed puberty
  • loss of secondary sexual characteristics in adults
  • early sign: loss of periods
  • lack of libido
  • infertility + impotence
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10
Q

what does TSH deficiency cause?
Symptoms

A

Hypothyoidism
- low thyroid hormones
- weight gain
- fatigue
- bradycardia
- non elevated TSH
- low T4
- intolerance to cold

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11
Q

what does ACTH deficiency cause?

A

ACTH controls cortisol
- low cortisol
- tired
- dizziness
- hypotension
- hyponatraemia
Can be life threatening

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12
Q

What are the common hormones in excess in abnormalities in pituitary function?

A
  • prolactin
  • GH
  • ACTH
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13
Q

What are the rare hormones in excess in abnormalities in pituitary function?

A
  • TSH
  • LH/FSH
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14
Q

What does HPA stand for

A

Hypothalamic-pituitary-adrenal

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15
Q

What do you do if you think a hormone is too low?

A

Stimulation test

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16
Q

What do you do if you think a hormone is in excess?

A

Suppression test

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17
Q

Adrenal axis tests

A

Deficiency- synacthen test, insulin stress test
Excess- dexamethasone suppression test

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18
Q

Who should an insulin stress test not be done on and why?

A

patients with ischaemic heart disease or epilepsy
risk of triggering coronary ischaemia or seizures respectively

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19
Q

GH axis tests

A

Deficiency: insulin stress test
Excess: glucose tolerance test

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20
Q

2 types of prolactin-secreting pituitary tumours

A

Large tumour = macro-adenoma (>1 cm)
Small tumour = micro-adenoma (<1 cm) (more common)

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21
Q

Outline micro-prolactinomas incl. symptoms

A
  • most common pituitary tumours
  • F>M
  • <1cm
  • presentation of menstrual disturbances (or hypogonadism in men), galactorrhoea, infertility
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22
Q

How can PCOS and micro-prolactinomas be distinguished

A

PCOS has:
- presence of androgenic symptoms
- less elevated prolactin levels
- absence of pituitary lesion on MRI

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23
Q

what is the most common cause of hyperprolactinaemia?
+ physiological causes

A

prolactinoma - pituitary adenoma that secretes prolactin

pregnancy
stress
Suckling
exercise
drugs

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24
Q

Causes of hyperprolactinaemia

A
  • medications e.g. anti-emetics, antipsychotics
  • PCOS
  • prolactinoma
  • non functioning adenoma causing compression of pituitary stalk
  • pregnancy
  • profound hypothyroidism (rare)
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25
Q

how does hypogonadism arise from hyperprolactinaemia?

A
  • increased plasma prolactin
  • higher levels of dopamine for negative feedback
  • dopamine inhibits GnRH secretion
  • inhibition of FSH + LH secretion
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26
Q

How are prolactinomas treated?

A
  • dopamine agonists e.g. cabergoline, bromocriptine
  • not operation
    Ensure patient isn’t pregnant
27
Q

What does dopamine inhibit?

A

Prolactin

28
Q

What does prolactin inhibit?

A

Luteinising hormone
Ovulation and secretion of sex hormones

29
Q

Symptoms on hyperprolactinaemia in women

A
  • menstrual disturbance
  • fertility problems - hypogondasim
  • galactorrhea - excessive or inappropriate milk production
  • gynecomastia - hard breast tissue
30
Q

Symptoms of hyperprolactinaemia in men

A
  • present later than women - no periods
  • larger tumours
  • low testosterone - hypogonadism
  • ED
  • may have mass symptoms e.g. visual loss
31
Q

What is Acromegaly
What is it due to?

A
  • Large extremities - Large hands and feet
  • due to GH secreting pituitary adenoma in adults
32
Q

Clinical features of acromegaly

A
  • increased size of feet + hands
  • coarser facial features over time
  • chin protrusion
  • widely spaced teeth
  • frontal bossing of forehead
  • enlargement of tongue + soft palate > snoring + sleep apnoea
  • sweating, headaches, hypertension, DM
33
Q

Complications of untreated acromegaly

A
  • premature cardiovascular death
  • irreversible changes in appearance
  • increased risk of thyroid + bowel cancer
  • hypertension
  • diabetes
34
Q

Investigations of acromegaly

A
  • oral glucose tolerance test
  • IGF-1 levels
  • MRI to identify pituitary adenoma
35
Q

Biochemical test to confirm acromegaly

A
  • oral glucose tolerance test resulting in failure to suppress GH
  • elevated IGF-1
36
Q

Treatment of acromegaly

A
  • Surgical removal of tumour
  • Radiation therapy
  • dopamine receptor agonists e.g. cabergoline
  • somatostatin analogues e.g. octreotide
37
Q

Drug treatment of acromegaly

A
  • dopamine agonists e.g. cabergoline
  • somatostatin analogues e.g. octerotide
38
Q

outline monitoring of disease activity in acromegaly

A
  • oral glucose tolerance test post-surgery to indicate persistent disease
  • periodic colonoscopy due to increased colon cancer risk
  • assessment for sleep apnoea, diabetes + cardiovascular disease due to increased risk
39
Q

what causes Cushing’s disease

A

ACTH-secreting pituitary tumour

40
Q

Changes in appearance in Cushing’s disease

A
  • round pink face
  • round abdomen
  • thin skin
  • bruises easily
  • striae/stretch marks
  • osteoporosis- thin bones
  • high BP
    -diabetes
  • skinny arms and legs
41
Q

What is primary polydipsia?

A

When patient has normally functioning ADH but drinks excessive amounts of water > polyuria

42
Q

What is Diabetes insipidus caused by?

A
  • Cranial DI: ADH deficiency - in pituitary disease
  • nephrogenic DI: ADH resistance in kidney - metabolic + electrolyte disturbance, renal disease or nephrotoxic drugs
43
Q

Causes of cranial diabetes insipidus

A
  • idiopathic
  • brain surgery/tumour/infection
  • damage to pituitary/hypothalamus gland
44
Q

Causes of nephrogenic diabetes insipidus

A
  • nephrotoxic medications e.g. lithium
  • hypercalcaemia
  • hypokalaemia
  • PCOS
  • renal disease
45
Q

Presentation of diabetes insipidus

A

polyuria
polydipsia
dehydration
postural hypotension

46
Q

Investigations + confirmation of diabetes insipidus

A
  • high serum osmolality
  • low urine osmolality
  • high urine volume (>3L per 24 hours)
  • U&Es
47
Q

Diagnosis of diabetes insipidus

A

water deprivation test

48
Q

Outline the water deprivation test / desmopressin stimulation test

A
  • patient avoids all fluids for 8 hours before test
  • urine osmolality is measured
  • if low, desmopressin (synthetic ADH) is given
  • urine osmolality measured over 24 hours after
49
Q

Outline the results of water deprivation test

A
  • primary polydipsia: high UO after deprivation
  • Cranial DI: low UO after deprivation + high UO after desmopressin
  • nephrogenic DI: low UO after depravation+ desmopressin
50
Q

Consequences of untreated diabetes inspidus

A
  • dehydration
  • hypernatraemia
  • reduced consciousness
  • coma
  • death
51
Q

Management of cranial diabetes insipdius

A
  • desmopressin (synthetic ADH)
  • monitor serum sodium - risk of hyponatraemia
  • investigate for pituitary disease
52
Q

Management of nephrogenic diabetes insipidus

A
  • treat underlying cause
  • stop damaging drugs
  • drink according to thirst
  • thiazide diuretics
  • NSAIDs
  • low salt
  • low protein diet
53
Q

What organ produces IGFs?

A

Liver

54
Q

outline the clinical approach of the investigation of a suspected pituitary tumour

A
  • endocrine function assessment: hormone levels + biopsy of tumour w antibiotics for hormone
  • visual field defects assessment
  • MRI scan
55
Q

what is hypopituitarism often due to?

A

pituitary adenoma > progressive loss of anterior pituitary function

56
Q

what is panhypopoituitarism?

A

deficiency in all anterior pituitary hormones

57
Q

What is hyperpituitarism?
What is it commonly caused by?

A
  • Excess pituitary hormone production (prolactin, GH + ACTH)
  • due to functional hypersecreting pituitary adenoma
58
Q

What is a pituitary apoplexy

A

Bleeding into or impaired blood supply of the pituitary gland

59
Q

Symptoms of pituitary apoplexy

A

Sudden onset headache
Double vision
Cardinal nerve palsy
Visual field loss
Hypopituitarism

60
Q

What is the most common causes of pituitary disorders?
Describe this

A

Pituitary adenoma
- benign tumour
- often non functioning (do not produce any hormones) - have negative effect due to pressure exerted

61
Q

What hormones are most commonly affected by Hypopituitarism?

A
  • ACTH
  • ADH
  • TSH
  • Growth hormone
  • Gonadotrophin (LH/FSH)
62
Q

What hormones are most commonly affected in hyperpituitarism?

A

Prolactin
Growth hormone
ACTH

63
Q

What can a GH excess cause in childhood vs adulthood?

A

Childhood - gigantism
Adulthood - acromegaly

64
Q

Why can growth hormones excess cause diabetes mellitus?

A

GH antagonises insulin

MEH (23 decks)

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