addison disease

Question 1

also known as

Answer 1

primary adrenal insufficiency

Question 2

what is addison disease

Answer 2

destruction of the adrenal cortex resulting in glucocorticoid (cortisol) and mineralocorticoid (aldosterone) deficiency

Question 3

most common cause of addisons disease in developed countries

Answer 3

autoimmune destruction of the adrenal cortex

Question 4

most common cause of addisons disease worldwide

Answer 4

tuberculosis

Question 5

other causes of addisons disease

Answer 5

adrenal metastasis (e.g from lung, breast, renal cancer), opportunistic infections in people with HIV (CMV, mycobacterium avium), watterhouse freidrichson syndrome, congenital adrenal hyperplasia

Question 6

adrenal cortex is made up of 3 layers

Answer 6

• zona glomerulosa
• zona fasciata
• zona reticularis

Question 7

the zona glomerulosa secretes

Answer 7

aldosterone which is part of the renin angiotensin aldosterone system which acts to:

• decrease plasma potassium concentration
• increase plasma sodium concentration
• increase blood volume and pressure

Question 8

aldosterone is secreted in response to elevated

Answer 8

levels of renin

Question 9

how does aldosterone work

Answer 9

• it binds to receptors on the principal cells on the distal convoluted tubule which stimulate the Na+/K+ pump which drives potassium from the plasma into the cells which then flows down its concentration gradient to be excreted as urine
• at the same time it also drives sodium from the cell into the plasma allowing more sodium to flow from the tubule into the blood down its concentration gradient, water flows in the direction of sodium via osmosis so blood volume increases and blood pressure increases

Question 10

aldosterone also stimulates

Answer 10

the proton ATPase in the alpha-intercalated cells causing more protons to be excreted into the urine meanwhile ion exchangers on the basal surface of the cell move the negatively charged bicarbonate ion into the extra-cellular space which increases the pH

Question 11

the hypothalamus

Answer 11

secretes corticotrophin releasing hormones (CRH) which stimulates the anterior pituitary to secrete adrenocorticotrophin hormone (ACTH) which targets the cells of the bona fasciulata specifically causing its cells to release cortisol

Question 12

cortisol main function is to

Answer 12

increase hepatic gluconeogenesis (glucose production from non-carbohydrate precursors) which increases the blood glucose levels

Question 13

the bona reticualris cells secrete

Answer 13

androgens including dehydroepiandrosterone which is a precursor of testosterone, adrenal glands are involved in the production of testosterone in men and woman but in men they only contribute a tiny amount as most is produced by the testes

Question 14

in males testosterone levels are

Answer 14

high and responsible for development of male reproductive tissue and secondary sex characteristics

Question 15

in females testosterone levels are

Answer 15

low and responsible for growth spurt in development, underarm and pubic hair in puberty and increased sex drive during adulthood

Question 16

in addisons disease

Answer 16

the adrenal cortex is destroyed so there is deficiency of cortisol and aldosterone so none of there processes can occur

Question 17

reduction in aldosterone production

Answer 17

causes potassium retention and sodium and water excretion this causes

• low blood volume and blood pressure which causes a compensatory tachycardia
• hyperkalaemia and hyponatraemia
• hypoviolaemia and metabolic acidosis

Question 18

reduction in cortisol

Answer 18

causes reduction in gluconoegensis so in times of stress can cause hypoglycaemia

Question 19

why does addisons disease cause hyperpigmentation

Answer 19

loss of cortisol means that no negative feedback takes place so the hypothalamus produces much more CRH than normal, this stimulates the anterior pituitary to produces PROPIOMELANOCORTIN which is a precursor to ACTH and MSH (melanocyte stimulating hormone) which causes hyper pigmentation

Question 20

loss of androgens (testosterone)

Answer 20

is not that symptomatic in males as they have enough produced from the testes out in females can cause loss of libido and sparse pubic and axillary hair

Question 21

addison disease has an

Answer 21

insidious onset and is commonly not picked up until a major physiological stress (infection, injury, surgery) causing an ADDISONIAN crisis where there is a sudden requirement for glucocorticoids and mineralocorticoids (but mostly cortisol)

Question 22

symptoms of addisons disease

Answer 22

• fatigue and weakness
• weight loss
• dizziness
• anorexia
• vomiting and diarrhoea
• abdominal pain
• hyper pigmentation
• postural hypotension
• sparse axially and pubic hair in females
• tachycardia
• depression

Question 23

metabolic abnormalities

Answer 23

• ACTH levels are elevated, cortisol levels are low
• hyponatraemia and hyperkalaemia
• increased renin and low aldosterone
• hypoglycaemia

Question 24

addisons is diagnosed using

Answer 24

the short synthacten test
measure plasma cortisol before and 30 minutes after an IV/IM injection of ACTH
- baseline >250 is normal
- post- ACTH >550 is normal

if the values are any less than these then this is abnormal

Question 25

to check if addisons is caused by autoimmune destruction

Answer 25

adrenal autoantibodies

Question 26

management of addisons disease

Answer 26

• hydrocortisone (to replace cortisol) 15-20mg daily

- fludrocortisone (to replace aldosterone)

Question 27

hydrocortisone can cause

Answer 27

exogenous cushings syndrome however, STEROIDS SHOULD NEVER BE STOPPED SUDDENLY IN ANYONE AS IT CAN TRIGGER AN ADRENAL CRISIS

Question 28

hydrocortisone and fludrocortisone can cause

Answer 28

secondary hypertension so blood pressure should be carefully monitored

Question 29

acute adrenal insufficiency is also known as

Answer 29

adrenal crisis

Question 30

acute adrenal insufficiency is

Answer 30

a life threatening condition where the body is acutely deprived of cortisol (and aldosterone)

Question 31

causes of acute adrenal insufficiency

Answer 31

• patients with addisons disease who have suddenly stopped there steroids to get an acute illness infection or surgery
• patients with meningococcemia (waterhouse- fredreichsen- syndrome)
• withdrawal of exogenous steroids
• pituitary necrosis (pituitary apoplexy, sheehans syndrome)
• post- bilateral adrenalectomy

Question 32

presentation

Answer 32

• severe vomiting and diarrhoea
• low blood pressure (hypotension)
• abdominal pain
• may have hyper pigmentation if they have addisons or a purpuric rash if caused by meningococcemia

Question 33

if you suspect adrenal crisis what should you do

Answer 33

carry out investigations but do not wait for the results treat immediately!!

Question 34

investigations of adrenal crisis

Answer 34

• hyponatraema and hyperkalaemia
• low cortisol and high ACTH
• hypoglycaemia
• blood urine and sputum culture is infection suspected

Question 35

management of adrenal crisis

Answer 35

• 100mg hydrocortisone
• IV fluids
• IV glucose if they are hypoglycaemic
• IV antibiotics if you suspect meningococcaemia

Question 36

waterhouse- friderichsen- syndrome

Answer 36

bilateral adrenal cortex haemorrhage most commonly caused by neisseria meningitidis (meningococcus)

Question 37

waterhouse-friderichsen- syndrome causes

Answer 37

an adrenal crisis

Question 38

symptoms of waterhouse- friderichsen- syndrome

Answer 38

• fever
• headache
• hypotension can cause shock
• purpuric rash
• abdominal pain

Question 39

INVESTIGATIONS for waterhouse-friedrichsen- syndrome

Answer 39

treat before they come back!!

• blood cultures
• abdominal CT
• Low cortisol levels
• hypoglycaemia, hyperkalaemia, hyponotraemia

Question 40

treatment of waterhouse-friedrichsen- syndrome

Answer 40

in ICU

• IV ceftriaxone
• IV hydrocortisone
• IV fluids