S10 Adrenal Disorders Flashcards
“The deeper you go, the sweeter it gets” so what is each level of the adrenal cortex related to?
Zona glomerulosa - mineralcorticoids - salt
Zona fasciculata - glucocorticoids - sugar
Zona reticularis - androgens - sex
What is the clinical presentation if a person has a cortisol deficiency?
- weakness
- tiredness
- weight loss
- hypoglycaemia
What is the clinical presentation if a person has a mineralocorticoid deficiency?
- dizziness, low Na+, high K+
What is the clinical presentation if a person has an androgen deficiency?
- low libido
* loss of body hair in women
What is the clinical presentation of a person with a cortisol excess?
- weight gain
* cushingoid features
What is the clinical presentation of a person with a mineralocorticoid excess?
- high BP
* low K+
What is the clinical presentation of a person with a androgen excess?
- increased male characteristics in women
What is the clinical presentation if there is excess ACTH released from the pituitary?
Skin pigmentation due to melanocytes stimulation - seen in Addison’s and ACTH-driven Cushing’s
What is the clinical presentation of someone with excessive catecholamine secretion?
Acute episodes of:
- sweating
- anxiety
- palpitations
- high/low BP
- collapse
What biochemical tests do you do if someone has a suspected adrenal hormone deficiency?
- electrolytes - low Na+, high K+ if aldosterone deficiency, if ACTH deficiency, only Na+ is low and K+ is normal
- 0900 basal cortisol - low (should be high in morning)
- stimulation test, inject with synthetic ACTH
What biochemical tests do you do if someone has a suspected adrenal hormone excess?
- electrolytes - low K+, high Na+
- midnight cortisol - high (should be low)
- 24hr urine cortisol - high
- suppression test - failure to suppress
- androgens and derivatives - high
What biochemical tests do you do to assess the adrenal medulla function?
- 24 hour urine catecholamines - adrenaline, NA, dopamine, 3-methoxy-tyramine
- 24 hour urine metanephrines (breakdown products of adrenaline and NA) - metadrenaline, normetadrenaline
- plasma metanephrines (more sensitive than 24hr urine)
Avoid coffee, coke, bananas, chocolate and vanilla before testing
What condition are high levels of catecholamines, in 24hr urine testing, suggestive of?
Phaeochromocytoma
What radiological imaging is used in adrenal disease?
- CT scan
- MRI scan
- functional imaging - MIBG scan (shows uptake of adrenaline/NA phaeochromocytoma) and PET scan
What are the signs and symptoms of Addison’s disease?
- fatigue and weakness
- anorexia and weight loss
- abdominal pain and nausea
- dizziness
- pigmentation
- underweight and signs of weight loss
- general malaise
- vitiligo and thyroid autoimmune diseases
- postural hypotension
- pigmentation
What can cause primary adrenal failure?
- autoimmune
- infection
- infiltration
- malignancy
- genetic
- vascular
- iatrogenic
What are the clinical features of adrenal crisis?
- collapse
- hypotension
- dehydration
- pigmentation
- coma
What are the blood test results of someone in adrenal crisis?
- low Na+
- high K+
- high urea
- high creatinine
How do you treat adrenal crisis?
- quick rehydration with fluids
- IV hydrocortisone
- correction of hypoglycaemia
- find out the precipitating cause
In someone with Addison’s what is their response to synthetic ACTH compared to normal?
Normal is an increase in cortisol
In Addison’s there is a flat/little/no response
How do you treat Addison’s disease in the long term?
- glucocorticoid - hydrocortisone and prednisolone
- mineralocorticoid - fludrocortisone
Educate to prevent a crises
- given double dose of glucocorticoid at times of illness
- emergency hydrocortisone injection is vomiting
- have a steroid card and bracelet
When does ACTH deficiency occur?
Any cause of hypopituitarism (could be due to a tumour)
What are symptoms of ACTH deficiency similar to?
Those in primary adrenal failure e.g. weakness, weight loss, nausea, fatigue, etc
However there is no pigmentation as ACTH isn’t raised and there’s no hyperkalaemia as there’s no mineralocorticoid deficiency.
Why does hyponatraemia occur in an ACTH deficiency?
Due to the effect of cortisol on free water excretion
How do steroids lead to hypoadrenalism? And hypoadrenal crisis?
When taking long-term steroids, ACTH is suppressed (negative feedback) - an abrupt withdrawal can lead to hypoadrenal crisis
What is Cushing’s syndrome?
A clinical syndrome due to glucocorticoid excess
What are the symptoms and signs of Cushing’s syndrome?
- round pink face
- round abdomen
- skinny and weak arms and legs
- thin skin that easily bruises
- red stretch marks/striae on abdomen
- high blood pressure and diabetes
- osteoporosis
What are 4 causes of Cushing’s syndrome?
- pituitary tumour
- ectopic ACTH
- steroid drugs
- adrenal tumour
What is ACTH-independent Cushing’s syndrome?
When ACTH is suppressed by the high cortisol levels
What is ACTH-dependent Cushing’s syndrome?
When ACTH isn’t suppressed - so it’s an issue with ACTH/pituitary or ectopic ACTH production
What androgenic is symptoms may be present with Cushing’s syndrome?
- abnormal facial hair growth in women
- acne
- greasy skin
If due to a large tumour:
- androgenic alopecia
- deep voice
- clitoromegaly
How do you treat Cushing’s syndrome?
Adrenalectomy - laparoscopic
But if it’s a large tumour need open surgery
What is primary hyperaldosteronism?
What are the two causes?
Excess production of aldosterone from the adrenal gland
- Aldosterone secreting adrenal adenoma - Conn’s syndrome
- Bilateral adrenal hyperplasia
What does primary hyperaldosteronism lead to?
Hypertension and hypokalaemia
The elevated aldosterone is independent of the the RAAS
what is congenital adrenal hyperplasia (CAH)?
A rare but important inherited disorder - autosomal recessive
Results in adrenal crisis and ambiguous genitalia due to a block in the adrenal cortex pathway.
The lack of enzyme leads to low cortisol and aldosterone and high male hormones (androgens)
What is the presentation fo congenital adrenal hyperplasia?
- hypotension
- hyponatraemia
- hyperkalaemia
- hypoglycaemia
- virilization - development of male physcial characteristic in a female
How do you treat congenital adrenal hyperplasia?
- treat the adrenal crisis - IV hydrocortisone, fluids, treat hypoglycaemia
- determine the sex of the baby
- long term glucocorticoid and mineralocorticoids
- corrective surgery
What is phaeochromocytoma?
A tumour of the adrenal medulla
What is paraganglioma?
An extra-adrenal tumour
What are the symptoms of phaeochromocytoma and paraganglioma?
Acute episodes of:
- sweating
- panic attacks
- palpitations
- high/low BP
- collapse
What occurs in an acute crisis in phaeochromocytoma and paraganglioma?
- hypertensive crisis
- encephalopathy
- hyperglycaemia
- cardiac arrhythmias
- sudden death
What investigations do you do to confirm phaeochromocytoma and paraganglioma?
- 24 hour urine metanephrines (need 2-3 collections)
- plasma metanephrines
- is chromogranin A present? (Neuroendocrine marker)
How do you manage phaeochromocytoma and paraganglioma?
- alpha and beta blockades - phenooxybenzamine and bisoprolol before surgery to remove tumour
- block alpha receptors before beta receptors otherwise get hypertensive crisis
What conditions are treated with corticosteroid drugs?
- skin conditions e.g. eczema
- asthma
- inflammatory bowel disease
- rheumatoid arthritis
- other autoimmune conditions
Why does someone with Cushing’s syndrome get abdominal obesity?
When there are high levels of cortisol lipogenesis increases and leads to fat distribution on the abdomen
(At low cortisol levels, lipolysis occurs)
Why do the arms and legs of someone with Cushing’s syndrome become thinner?
Muscle wasting due to proteolysis of muscle
What is the low dose cortisol suppression test?
Give low douses of glucocorticoids e.g. dexamethasone if you screening to determine what a patient has. If cortisol is suppressed, no Cushing’s, if not, then Cushing’s
What is the high dose cortisol suppression test?
Give high doses of glucocorticoid e.g. dexamethasone to see if the pituitary is working to reduce cortisol levels.
It is given in such high doses that some negative feedback would occur so even with a pituitary tumour, ACTH will decrease. However if the high cortisol levels are due to an ectopic tumour producing ACTH, then even if ACTH levels are being lowered in the pituitary, there’s still high ACTH as ACTH secreted from an ectopic tumour won’t be effected by high glucocorticoid levels
Why do you get hyperpigmentation in Addison’s disease?
Have low levels of cortisol so ACTH synthesis is increased to try and bring back up the cortisol levels (negative feedback), ACTH is produced from POMC cleavage, another product is MSH (melanin-stimulating hormone) so needing more ACTH, results in more POMC so more MSH produced leading to increased skin pigmentation
