Pituitary Flashcards by Imogen Smedley

What hormones are secreted by the anterior pituitary?

FLAT PIG
FSH
LH
ACTH
TSH
PRL
MSH
GH

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What is hormones are secreted by the posteriorly pituitary?

ADH vasopressin

Oxytocin

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Why does hypopituitarism present earlier in pre-menopausal women?

Since get secondary amenorrhea

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Hypopituitarism is a deficiency of 1 or more hormones produced by the pituitary gland - true or false

True

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What are trophic hormones?

Produced by anterior pituitary

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What is the commonest cause of hypopituitarism?

Pituitary adenoma

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How does a pituitary adenoma cause hypopituitarism?

Pituitary adenoma secretes excess of 1 type of hormone which causes deficiency of other hormones

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Name 2 iatrogenic causes of hypopituitaism

Head irradiation

During surgery

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What is a macro and microadenoma?

Micro <1cm

Macro >1cm

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What visual field defect can a pituitary adenoma cause?

Bitemporal hemianopia

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What visual field defect can a craniopharyngioma cause?

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In hypopituitarism, what is the general order for loss of pituitary hormone function?

GGAT

Gonadotrophins > GH > ACTH > TSH

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What is Sheehan’s syndrome?

Vascular cause of hypopituitarism - to severe hypotension eg in obstetric blood loss

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What is pituitary apoplexy?

Infarction or haemorrhage of pituitary gland

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TB, syphilis and AIDS can all cause hypopituitarism - true or false

True

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A craniopharyngioma can cause hypopituitarism - true or flase

True (compression)

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When investigating hypopituitarism, measure pituitary hormones + those that they stimulate. Which 2 hormones are less useful to measure since they have variable release?

Cortisol, growth hormone

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What type of imaging is best to visualise the pituitary?

MRI

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When investigating hypopituitarism, measure pituitary hormones + those that they stimulate. Which hormones are measured?

TSH, fT4, LH/FSH, estrogen/ testosterone

all low

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ITT insulin tolerance: give _____, causes _____, should see rise in _____ + _____

ITT insulin tolerance: give INSULIN, causes HYPOGLYCAEMIA, should see rise in CORTISOL + GROWTH HORMONE

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ACTH-oma is also known as what?

Cushing’s disease

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GH-oma is also known as what?

Acromegaly

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Acromegaly causes gigantism in children if onset before _____

epiphyseal fusion

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What effect does Cushing’s disease have on

face shape
mood
energy levels
body composition
BMI
glucose
hair
menstruation

Moon face
Depression
Low energy
Lemon on sticks
High BMI
Hyperglycaemia
Thin hair / hirsutism
Oligomenorrhea

(Also: frequent infections, poor concentrations, buffalo hump, poor wound healing, hypertension)

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What is seen on an ABG in Cushing's disease?

Hypokalaemic metabolic alkalosis

What features of Cushing's disease are specific and help differentiate it from obesity?

Osteoporosis Proximal myopathy Frontal balding Striae stretch marks (purple)

Name 3 causes of Cushing's syndrome

Cushing's disease Exogenous steroids Adrenal tumour/hyperplasia Exogenous ACTH from SCLC

What is the initial investigations for Cushing's?

Low dose overnight dexamethasone suppression test

What is the low dose overnight dexamethasone suppression test?

Cortisol is too high - so try and suppress it Giving dexamethasone should stop (suppress) cortisol production) Give 1mg dexamethasone overnight - then measure in morning cortisol - if cortisol still high requires further testing Patients without Cushing's will have their morning cortisol spike suppressed

Pituitary adenoma can cause a headache - true or false

It can do

What test is used to differentiate between Cushing's and pseudo-Cushing's?

Insulin stress test

The low dose 1mg dexamethasone test tests for presence of Cushing's syndrome and the high dose dexamethasone test localises the pathology of Cushing's syndrome - true or false

True (i think)

What is the high dose 8mg dexamethasone suppression test?

Give higher dose of dexamethasone and then measure cortisol + ACTH

Following high dose 8mg dexamethasone suppression test in ectopic ACTH secretion - are cortisol and ACTH suppressed?

Cortisol - not suppressed | ACTH - not suppressed

Following high dose 8mg dexamethasone suppression test in Cushing's disease - are cortisol and ACTH suppressed?

Cortisol - suppressed ACTH - suppressed (Pituitary secreting excess ACTH, so when give

Following high dose 8mg dexamethasone suppression test in an adrenal adenoma/ hyperplasia - are cortisol and ACTH suppressed?

Cortisol - not suppressed | ACTH - suppressed

What is the commonest pituitary adenoma?

Prolactinoma

How is a prolactinoma diagnosed?

Measure PRL > MRI

How is a micro v maro prolactinoma differentiated?

MRI 6mth apart

What is the 1st line management of a prolactinoma?

Dopamine agonist cabergoline

Can acromegaly cause hepatosplenomegaly?

Yes

What is the first line investigation for acromegaly?

Measure IGF-1 OGGT oral glucose tolerance test (glucose should suppress GH, +ve if stays same), (then MRI pituitary)

What is the first line management of acromegaly?

Trans-sphenoidal surgery | 2nd line somatostatin analogue octreotide

What are the 2 types of diabetes insipidus?

Cranial and nephrogenic

What is the basic pathology of diabetes insipidus?

Too little ADH

What drug causes nephrogenic diabetes insipidus?

Lithium

What is the presentation of diabetes insipidus?

Polydipsia, polyuria

In diabetes insipidus, is plasma osmolality high or low? Is urine osmolality high or low?

Low urine osmolality (very dilute urine) | High plasma osmolality (high plasma Na/urea)

What is the first line investigation for diabetes insipidus?

Water deprivation test

Ambiguous results on a water deprivation test suggest what cause?

Psychogenic polydipsia

What is the management of cranial diabetes insipidus?

Synthetic ADH vasopressin

What is the management of nephrogenic diabetes insipidus?

Treat/stop cause

For DI, in a positive water deprivation test result, following water deprivation urine osmolality _____ + plasma osmolality _____. Then give exogenous ____, in cranial DI urine osmolality _____ and in nephrogenic DI urine osmolality ______.

For DI, in a positive water deprivation test result, following water deprivation urine osmolality STAYS SAME + plasma osmolality INCREASES. Then give exogenous ADH, in cranial DI urine osmolality INCREASES and in nephrogenic DI urine osmolality STAYS LOW

Is plasma osmolality low or high in SIADH?

Low plasma osmolality | lower than urine osmolality

Is sodium low or high in SIADH

Low sodium

What is the presentation of SIADH?

Confusion, lethargy, muscle cramps, N&V, oliguria, symptoms of underlying cause

What malignancy may cause paraneoplastic SIADH?

SCLC | Loads of others too

Can pneumonia cause SIADH?

Yes

What is the first line management of SIADH?

Fluid restriction

What drug can be used in the management of severe SIADH?

Tolvaptan

Why must sodium be corrected slowly in SIADH

To prevent central pontine myelinolysis