Clinical Aspects of Adrenal Disorders Flashcards
What is the name for 1y adrenal insufficency/hyposecretion?
Addison’s disease
Causes of addisons?
Autoimmune
Infection
Infarction
Iatrogenic
What enzyme is commonly affected in the “adrenal enzyme defects” that cause hypo-secretion?
21-hydroxylase
What infiltrates the cortex in autoimmune addisons?
Lymphocytes
What other associated autoimmune diseases are common in people with autoimmune addisons?
Thyroid disease
Type 1 DM
Premature ovarian failure
Symptoms associated with 1y adrenal failure/ Addisons?
Weakness/fatigue Weight Loss Skin pigmentation/Vitiligo Hypotension Vomiting/diarrhoea Salt cravings
Why does Addisons cause tanned skin/pigmentation?
High levels of circulating ACTH binds to the melanocortin 1 receptor on the surface of dermal melanocytes
What are some clues that can leads you from symptoms to diagnosis of adrenal failure?
A disproportion between severity of illness and circulatory collapse/hypotension/dehydration
Unexplained hypoglycaemia
Other endocrine features - hypothyroidism, body hair loss,
Amenorrhoea
Previous depression or weight loss
What is amenorrhoea?
Absence of a menstrual period in women of reproductive age
Tests to diagnose adrenal insufficiency ?
Routine bloods - Us and Es, FBCs
Random cortisol - If over 700 nmol/l it isn’t Addisons but if under 700 it is suspected
Synacthens test - injecting ACTH to see if adrenal gland responds properly
Should you do synacthens test in an unwell patient?
No - if suspicion is there just start treatment an do the test later
If a synacthens test comes back normal doe sit rule of adrenal insufficiency all together?
No - only rules out 1y adrenal insufficiency
How would you tell if the adrenal insufficency was 1y or 2y?
1y would have elevated ACTH in blood while 2y would have supressed
Treatment for addisons?
Glucocorticoid replacements (cortisol) = Daily doses of hydrocortisone 20-30mg for rest of life. Given in divided doses to mimin normal diurnal variation
Other drugs such as prednisolone and dexamethasone can be used bu aren’t commonly used
Mineralocorticoid replacements (aldosterone) =
A synthetic steroid - fludrocortisone 50-300 micrograms daily
What is diurnal?
During the day
What patients need special care in their treatments?
Hypo-adrenal patients on replacement steroids
Patients on steroids on doses high enough to supress the pituitary adrenal axis (7.5mg prednisolone daily)
Patients who recently just received treatment and whose Hypothalamus-pituitary axis may still be suppressed
What action should be taken for these patients who have a minor or short lived illness?
Double the glucocorticoid dose
What action should be taken for these patients who have had a major illness or operation?
100mg hydrocortisone IV-stat
50-100mg HV IV-hourly
As stress abates - reduce HC by 50% per day until back on usual replacement dose
What is the three important ‘self-care’ rules for patients on steroids?
Never miss a dose
Double the HC dose in event of intercurrent illness - flu, UTI etc
If severe vomiting or diarrhoea call for help without delay - likely to need IM HC injection
What is the most common endocrine cause of hypertension?
1y hyperaldosteronism
Causes of a 1y hyperaldosteronism?
Unilateral adenoma
Bilateral hyperplasia
Name some rarer endocrine causes of hypertension?
Cushing's Acromegaly Hyperparathyroidism Hypothyroidism Pheochromocytoma
What is hyperaldosteronism called?
Conn’s disease
What is hypersecretion of Cortisol called?
Cushing’s syndrome
Causes of cushing’s syndrome?
Adenoma
CArcinoma
Bilateral hyperplasia
What area of the adrenal gland does Conn’s and Cushing’s affect?
cortex
What hypersecretory disease comes from damage to the medulla?
Pheochromocytoma - excess catecholamines
What sort of hormone is cortisol? What is some of it’s effects
A catabolic hormone
Causes tissue breakdown (weakness of skin, muscle and bone), Na retention (heart failure/HT) and insulin antagonism (DM)
Classic cushing’s signs and symptoms?
Central obesity Hypertension Purple striae Moon face Poor wound healing and bruising Personality changes - depression, mood swings wtc
Is it cushings syndrome if it is caused by a pituitary tumour?
No it makes it cushing’s DISEASE
Causes of ACTH dependant Cushings?
Pit gland tumour - 75%
Ectopic ACTH secretion - e.g from a lung carcinoid - rare = 5%
ACTH independent cushings causes?
Adrenal tumour - adenoma or carcinoma
Corticosteroid therapy
Screening test for cushings?
24 hr urinary free cortisol - normal 14-135 nmol/L
1mg overnight dexamethasone suppression test taken at midnight - normal = <50nmol/l at 9am
How does xs aldosterone affect the body?
Causes excretion of K+ = hypokalemia
Increase in blood volume and pressure due to retention of sodium
Also throws the aldosterone-renin ratio out of balance as increased aldo decreases renin
Symptoms/signs for conn’s?
May be asymptomatic
Can get muscle pains, spasms or tingling
Excessive urination
Signs include high BP and hypokalemia
Screening for conn’s?
PA/PRA (Plasma adlo/plasma renin activity) test ratio - >20 = 1y hyperaldosteronism
If less than 20 either 2y hyperaldosteronism or essential hypertension - less reliable reading though
Confirmatory test for conn’s?
24 hr tests
Urine aldosterone = 12 micrograms/day
Urinary sodium - 200mEq/day during 4 days of salt loading
What does Phaeochromocytoma cause?
Hypertension
Paroxysmal attacks
What is involved in a paroxysmal attack?
Headache Sweating Palpitations Tremor Pallor Anxiety/fear
What is most cases of congenital adrenal hyperplasia caused by?
21-hydroxylase deficiency
Approach for congenital adrenal hyperplasia?
Is there clinical suspicion?
Test for functioning status - is it functioning? If not - 1y or 2y?
What is the cause?
If tumour - can it be removed?
