Dopamine Agonists - Cabergoline (first choice) - Bromocriptine - Quinagolide

Pituitary Flashcards by S B

what hormones are produced in anterior pituitary

ACTH
TSH
LH/FSH
GH
Prolactin

How well did you know this?

Not at all

Perfectly

what are the peripheral counterparts of the hormones of the anterior pituitary

ACTH – Cortisol
TSH – Thyroxine
LH/FSH – Testosterone or Estradiol
GH – IGF-1

How well did you know this?

Not at all

Perfectly

what are hormones are baseline tests done on

TSH, fT4
LH/FSK
Testosterone 
GH
IGF-1 
PRL

How well did you know this?

Not at all

Perfectly

what is the principle of dynamic tests

too much hormone - try to suppress it

too little hormone - try to stimulate it

How well did you know this?

Not at all

Perfectly

what are the Dynamic Pituitary Function Stimulation Tests

Synacthen (synthetic ACTH)

Insulin stress test or
Prolonged Glucagon test

Water deprivation test

How well did you know this?

Not at all

Perfectly

what are the two classifications of pituitary tumours

≤ 1cm: Microadenoma

> 1cm: Macroadenoma

How well did you know this?

Not at all

Perfectly

what can a non functioning pituitary adenoma cause

Compression on optic chiasma
Compression on other structures 			eg cranial nerve 3,4,6
Hypoadrenalism
Hypothyroidism
Hypogonadism
(Diabetes Insipidus)
GH deficiency

How well did you know this?

Not at all

Perfectly

what is the typical vision loss associated with a pituitary adenoma

Bitemporal hemianopia

How well did you know this?

Not at all

Perfectly

what can cause raised prolactin

Physiological

breast feeding + pregnancy
stress
sleep

Drugs

Hypothyroidism

Stalk lesions - iatrogenic, road accident

Prolactinoma

How well did you know this?

Not at all

Perfectly

what drugs cause raised prolactin

Dopamine antagonists eg metoclopramide
Antipsychotics e.g. phenothiazines
Antidepressants
others e.g. estrogens, cocaine

How well did you know this?

Not at all

Perfectly

what affect does dopamine have on prolactin

negative feedback

e.g. increase dopamine, decrease prolactin and vice versa

How well did you know this?

Not at all

Perfectly

Sx of raised prolactin

Female

early presentation
galactorrhoea
menstrual irregularity
amenorrhoea
infertility

Male

late presentation
impotence
visual field abnormal
headache
anterior pituitary malfunction

How well did you know this?

Not at all

Perfectly

what is a Prolactinoma

benign tumour (adenoma) of the pituitary gland that produces prolactin

How well did you know this?

Not at all

Perfectly

Ix for prolactinoma

Serum prolactin
MRI pituitary
Visual fields Ex
Pituitary function test

How well did you know this?

Not at all

Perfectly

Mx of prolactinoma

Dopamine Agonists

Cabergoline (first choice)
Bromocriptine
Quinagolide

How well did you know this?

Not at all

Perfectly

what is acromegaly also known as if it is before epiphyseal fusion

gigantism

How well did you know this?

Not at all

Perfectly

what are features of acromegaly

thickened soft tissue
hypertension
cardiac failure
headaches
snoring/sleep apnoea
DM
Visual field loss
Hypopituitarism 
Early CV death
Colonic polyps and colon cancer

How well did you know this?

Not at all

Perfectly

Diagnosis of acromegaly

IGF-1 will be raised

Oral glucose tolerance test (suppression test)

How well did you know this?

Not at all

Perfectly

other Ix of acromegaly

visual fields
CT/MRI pituitary
Pituitary function tests

How well did you know this?

Not at all

Perfectly

when is drug therapy used in acromegaly

either in-operably tumour
OR
post surgery, GH > 1

How well did you know this?

Not at all

Perfectly

what does GH antagonist Pegvisomant do

binds to GH receptor and blocks GH activity
does not decrease tumour size
last line in therapy

How well did you know this?

Not at all

Perfectly

what are the hormone imbalances seen in Cushing’s Syndrome

excess Cortisol
excess mineralocorticoid
excess androgen

How well did you know this?

Not at all

Perfectly

what does excess cortisol cause

Protein loss

Myopathy; wasting
Osteoporosis; fractures
Thin skin; striae, bruising

Altered Carbohydrate/Lipid metabolism; Diabetes mellitus, Obesity

Altered psyche; psychosis, depression

How well did you know this?

Not at all

Perfectly

what does excess mineralocorticoid cause

hypertension

oedema

what does excess androgen cause

Virilism Hirsutism Acne oligo/amenorrhoea

what is Cushing's characterised by

``` Thin Skin Proximal myopathy Frontal balding in women Conjunctival oedema (chemosis) Osteoporosis ```

what is the SCREENING test for Cushing's

Overnight 1mg dexamethasone suppression test (oral)

what values are suggestive for Cushing's in an overnight dexamethasone suppression test

Cortisol > 100 = abnormal

what is the DEFINITIVE test for Cushing's

2 day 2mg/day Dexamethasone suppression test

what result on the definitive test would suggest there is no Cushing's

Cortisol

what are some causes of Cushing's syndrome

Pituitary adenoma Adenoma of adrenal Ectopic cancer (thymus/lung/pancreas) Pseudo - alcohol, depression, steroids

if the cause of Cushing's was ectopic what would the Ix show

Abnormal Low dose Dexa Test | ACTH > 300

if the cause of Cushing's was pituitary what would the Ix show

Abnormal Low dose Dexa Test | ACTH

if the cause of Cushing's was adrenal what would the Ix show

Abnormal Low dose Dexa Test | ACTH

Tx for Cushing's

Pituitary cause - transsphenoidal pituitary adenomectomy Adrenal cause - Adrenalectomy Ectopic cause - remove source or bilateral adrenalectomy

what can testosterone cause

polycythaemia | - abnormally increased concentration of haemoglobin in the blood

what goes growth hormone do in adults

``` decreases abdo fat increases muscle mass, strength, exercise, capacity, stamina improves cardiac function decreases cholesterol and increases LDL increases bone density ```

how is GH given

daily SC injection

what are the risks of testosterone replacement

prostate enlargement - problem if pre-existing prostate cancer Polycythamia - monitor FBC Hepatitis - only from oral tablets, monitor LFTs

what is the anterior pituitary also known as

Adenohypophysis

what is the neurohypophysis also known as

posterior pituitary

what is the anterior pituitary gland derived from and what does it do

the Rathke's pouch | area where hormones are secreted

what are the trophic and non-trophic hormones secreted from the anterior pituitary

trophic - TSH, ACTH, FSH, LH non-trophic - GH and Prolactin

what is the posterior pituitary derived from

Extension of neural tissue consists of modified glial cells and axonal processes

what hormones does the posterior pituitary secrete

ADH (vasopressin) | Oxytocin

what conditions can affect the posterior pituitary

Diabetes insipidus | Syndrome of inappropriate ADH secretion (SIADH)

what is diabetes insidious

lack of ADH secretion | can lead to life threatening dehydration

what is SIADH

Ectopic secretion of ADH by tumours | Primary disorder in the pituitary

what is pituitary adenomas associated with

MEN 1

how are pituitary adenomas classified

by cell type and the hormone they produce

what can a large adenoma lead to

visual field defects | panhypopituitarism

what are the common functional pituitary adenoma

Prolactinoma Growth hormones secreting ACTH secreting

what is the most common ACTH secreting tumour

Bilateral adrenocortical hyperplasia

what is a craniopharyngioma and what is it derived from

Benign brain tumour Derived from remnants of Rathke’s pouch

features of a craniopharyngioma

slow growing, often cystic, may calcify | excellent prognosis

symptoms of craniopharyngioma

headaches visual disturbances may cause growth retardation in children

Tx of craniopharyngioma

Radiation

when do craniopharyngioma present

50% in childhood

Sx of craniopharyngioma

children - growth failure adults - amenorrhea, decreased libido, Diabetes insipidus)