cushings/hypopituitarism/diabetes insipidus

Question 1

what is cushings syndrome

Answer 1

the term is used to refer to the signs and symptoms that develop after prolonged elevation of cortisol

excess cortisol >
protein loss ie myopathy, osteoporosis, thin skin, altered carbohydrate/lipid metabolism and altered psyche

excess mineralocorticoid > HPT, oedema

excess androgen > virilism, hirsutism, acne, oligo/amenorrhea

Question 2

what is cushings characterised by

Answer 2

thin skin - striae, bruising
proximal myopathy
frontal balding in women
conjuncitval oedema
osteoporosis
moon face
buffalo hump

not just obese

“lemon on matchsticks”

Question 3

screening tests for cushings

Answer 3

dexamethasone suppression test
if cortisol >130mmolL that is abnormal

(dexamethasone should negatively feedback on the hypothalamus and pituitary (lowers ACTH and CRH) and so if cortisol is not suppressed we see cushings syndrome

urine free cortisol
if cortisol/creatinine ratio is <25 that is normal

diurnal cortisol variation

MRI brain

chest CT

abdominal CT

Question 3

diagnostic tests for cushings

Answer 3

high dose dexamethasone

Question 4

what is cushings disease

Answer 4

pituitary tumour pathology

Question 5

what causes cushings syndrome (overall)

Answer 5

exogenous steroids (ie long term high dose patients)

cushings disease (pituitary adenoma releasing excessive ACTH)

adrenal adenoma

paraneoplastic cushings ie when excess ACTH is released from a cancer ie SCLC

Question 6

tx for cushings

Answer 6

pituitary - hypophysectomy and external radiotherapy if recurs
bilateral adrenalectomy

adrenal - adrenalectomy

ectopic - remove or bilateral adrenalectomy

Question 7

drug tx for cushings

Answer 7

metyrapone

ketaconazole (heptatoxic)

pasireotide LAR (somatostatin analogue)

Question 8

causes of hypopituitarism

Answer 8

> pituitary tumours

> other local brain tumours

> iatrogenic surgery

granulomatous disease

vascular disease

trauma

secondary metastatic lesions

autoimmune

Question 9

clinical signs of hypopit.

Answer 9

menstrual irregularities
infertility/impotence
gynaecomastia
abdominal obesity
loss of facial hair
loss of axillary and pubic hair
dry skin and hair
growth retardation
hypothyroid face

Question 10

tests for hypopit. anterior pit hormones

Answer 10

Question 11

tx for hypopit.

Answer 11

goal = hormone replacement

thyroxine 100-150mcg
hydrocortisone 10-25 mg and split 2-3 times per day
ADH desmospray
GH nightly
sex steroids

Question 12

how to inject testosterone

Answer 12

IM injection every 3/4 weeks

skin gel (testogel)

prolonged IM injection 10-14 weeks (nebido)

Question 13

what are the risks of testosterone replacement

Answer 13

polycythaemia

prostate enlargement - does not cause cancer but if its already there can make it grow

hepatitis

Question 14

benefit of growth hormone replacement

Answer 14

improves well-being and quality of life
improves bone strength etc

Question 15

causes of cranial DI

Answer 15

familial -
DIDMOAD

acquired -
idiopathic
trauma
tumour

Question 16

diagnostic test for DI

Answer 16

water deprivation test

check serum and urine osmolalities for 8hour and then 4 hour after giving IM DDA VP

> 1.8-2 then normal otherwise DI

Question 17

treatment for DI

Answer 17

desmospray
nasally - 10-60mcg/day

desmopressin oral tablets
100-1000mcg/oer day

desmopresson injection
1-2mcg IM per day

Question 18

a baseline urine to serum osmolality >2 usually avoids the need for a water deprivation test
T/F

Answer 18

true

Question 19

what are clinical signs of hypercortisolism

Answer 19

HPT
cardiac hypertrophy
hyperglycaemia (T2DM)
depression
insomnia

Question 20

what is hypopituitarism

Answer 20

when the pituitary does not produce a number of pituitary hormones

Question 21

A 60 year old man with Acromegaly has been under the care of the neurosurgeons for a pituitary operation to remove his pituitary tumour. 3 months after the operation he starts to become symptomatic with sweats, raised glucose levels and headaches. He is found to still be biochemically producing excess growth hormone. Which of the following medication types would be the best first line to treat his condition?

Answer 21

somatostatin analogues

eg octreotide are used 1st line generally to control excess GH - they work by blocking GH production

Question 22

how does cortisol increase plasma glucose

Answer 22

inhibits insulin-mediated glucose disposal

can often get DM with Cushings

Question 23

A 48 year old woman presents to her GP with newly diagnosed type 2 diabetes. She also describes central weight and sweats. Her mood has been irritable for several months and she feels generally weak, tired and run down even after she has been started on oral hypoglycaemic medication and her glucose levels normalise.

Which of the following is the best initial investigation?

Answer 23

suspect cushings >

overnight dexamethasone test

*screening = key word