Adrenals

Question 1

What is Addison’s disease?

Answer 1

Primary adrenal insufficiency
- autoimmune destruction

Low aldosterone - hypovolemia, hyponaterimia, hyperkalemia, metabolic acidosis.

Low cortisol - weak, tired. Over activity in pituitary … increased in melanocytes stimulating hormone … pigmented skin (mainly in joints)

Low androgens… women decreased sex drive, pubic hair loss

Question 2

What’s the action of aldosterone?

Answer 2

Acts on sodium-potassium pump, and ATPase pump (⬇️ H+)

Decreases K+
Increases Na+
Increase blood volume and pressure

Question 3

Where is cortisol released from?

Answer 3

Zone fasciculata

Question 4

What’s the action of cortisol?

Answer 4

Increases blood glucose levels (gluconeogenisis in liver) (amino acid from muscle) and (free fatty acid from adipose tissue)

Question 5

What is symptoms are seen in an Addisonian crisis?

Answer 5

Pain in back,
Vomiting and diarrhoea,
Low blood pressure ,
Death!

Question 6

What is Waterhouse friederichsen syndrome?

Answer 6

Sudden increase in blood pressure leads to rupture of adrenal vessels, ischemia and adrenal gland failure —- addisonian crisis

Question 7

What’s the diagnostic test for Addison’s disease?

Answer 7

1) measure random cortisol - usually <100nmol/L
2) short ATCH stimulation test - after 30mins lack of response to exogenous ATCH (<600)
3) plasma ATCH - determines 1’ vs 2’ and 3’ hypoadrenalism.

4) long ATCH stimulation test - hourly intervals 5hrs then 8 for 24hrs.
Normal - increase >1000 in 4 hours >550 over baseline
Addisons - impaired throughout
Secondary - delayed but normal response seen.

5) adrenal autobodies

Question 8

Management of Addison’s disease?

Answer 8

Hydrocortisone (20mg AM, 10mg PM)

Fludrocortisone (50-300 ug, OD) adjust to normal electrolyte, blood pressure and renin levels.

Double dose during illness.

Question 9

What’s secondary hypoadrenalism?

Answer 9

Pituitary produces no or low ATCH

Treatment with hydrocortisone

(Or Could be due to long term steriod therapy)

Question 10

What tumours can cause Cushing’s syndrome?

Answer 10

Pituitary tumour
Ectopic ACTH tumours (small cell lung cancer, carcinoid tumours)

Adrenal adenomas
Adrenal carcinomas

Question 11

How to diagnose Cushing’s syndrome?

Answer 11

48hrs, low dose dexamethosone suppression test (normal - cortisol <50 2 hours after last dose of dex)

24hr urinary free cortisol (normal - <700nmol/24hrs)

Circadian rhythm studies

Then detect CAUSE eg ATCH and cortisol levels 9am vs midnight, high dose dex suppression test, CRH stimulation.

Question 12

What condition is 5-HIAA increased in?

Answer 12

Phaeochromocytoma

Question 13

Which antibody is associated with Addison’s disease?

Answer 13

21-hydroxylase auto-antibodies

Question 14

What causes blood test results in congential adrenal hyperplasia?

Answer 14

Low aldosterone (salt wasting Crisis , ⬆️K+ and H+), 
low cortisol (low glucose, high ACTH - hyperplasia), 
high testosterone (virilization of external genitalia in females, males - no symptoms or larger penis or precocious puberty)

Commonly 90% (AR) - Due to gene disfunction of 21-hydroxylase enzyme (CYP21A2) increased shunting to ZR layer and increase testosterone.

Question 15

How to diagnose congential adrenal hyperplasia?

Answer 15

Bloods - high 17-hydroxy-progesterone, +/- ATCH stimulation test.

Genes - CYP21A2 gene

Carrier screening

Karyotype !!

Hormone Levels

Question 16

How to treat congential adrenal hyperplasia?

Answer 16

Peds endocrinologist
Adrenal insufficiency - give fludrocortisone (min) and hydrocortisone (glu).
Salt wasting - increase steriods, give sodium/ fluids/glucose
? Surgery for ambiguous genitalia.

Question 17

In Addison’s what’s the advice for steroids and sick day rules?

Answer 17

Keep fludrocortisone same

Double glucocorticoids

Question 18

What features are seen in conns syndrome?

Answer 18

Cons is high aldosterone-- leads to hypernatermia (thrist) and hypokalemia (muscle weakness) and alkalosis (loss of +H).
Also hypertension (resistant to treatement)

Question 19

What are the features of phaeochromocytoma?

Answer 19

Hypertension, headaches, papitations, sweating, anxiety

Question 20

Diagnositic test for phaeochromocytoma?

Answer 20

24hour urinary collection of metanephrines (or vanillymandelic acid or catecholaimes)

Blood test for metanephrine.

Ct and MRI to localise the lesion.

Question 21

Treatment of phaeochromocytoma

Answer 21

Surgery is definitive Mx

But stabilise with medical management first:

• alphablocker - phenoxybenzamine
• beta blocker - propanol

Question 22

What investigations for conns syndrome?

Answer 22

Renin:aldosterone ratio.

High resolution CT abdominal

Adrenal vein sampling