adrenal disease Flashcards
what does the zona glomerulosa produce
mineralocorticoids (e.g. aldosterone)
what does the zona fasiculata produce
glucocorticoids (cortisol)
what does the zona reticularis produce
androgen precursors (e.g. DHEA)
what does the medulla produce
catecholamines (e.g. adrenaline, noradrenaline)
what is the zona glomerulosa controlled by
renin angiotensin system
what is the zona fasciculata controlled by
CRH (hypothalamus) and ACTH (anterior pituitary)
what is the zona reticularis controlled by
CRH (hypothalamus) and ACTH (anterior pituitary)
what is the medulla controlled by
sympathetic nervous system
what is the effect of the zona glomerulosa
- increased sodium and water reabsorption
- increased potassium secretion
what is the effect of the zona fasciculata
- increased metabolism
- increased blood pressure
- anti-inflammatory effects
what is the effect of the zona reticularis
precursors used to produce sex steroids (testosterone)
what is the effect of the medulla
- increased heart rate/contractility
- increased vasoconstriction
- bronchodilation
what is primary adrenal insufficiency
- any condition associated with a reduction of steroids (mainly cortisol and aldosterone) due to failure within adrenal glands
- due to the negative feedback control of cortisol production, reduced levels will be associated with an increase in ACTH (causes increased skin pigmentation)
primary adrenal insufficiency causes
- infection: TB
- adrenal metastasis: lung, breast, renal, lymphoma
- autoimmune: Addison’s (most common cause)
- Waterhouse Friderichsen’s Syndrome (bilateral adrenal haemorrhage due to sepsis)
primary adrenal insufficiency presentation
- myalgia, arthralgia
- dizziness, weakness
- depression, psychosis
- abdominal pain, diarrhoea, vomiting
- lethargy, weight loss, hypoglycaemia, hypotension
- hyperpigmentation of skin (esp. palmar creases)
- vitiligo
- postural hypotension
primary adrenal insufficiency diagnosis
- bloods: low sodium, high potassium, low glucose
- diagnostic: short synacthen test
- give synthetic ACTH: cortisol should increase (normal)
- measure cortisol before and then 30-60mins after
- normal results: baseline >170, 30-mins >550
- Addison’s disease: no significant rise in cortisol
- chest x-ray
- CT CA
primary adrenal insufficiency management
steroid replacement
- aldosterone deficiency: 50-200mg fludrocortisone
- cortisol deficiency: 15-25mg hydrocortisone (given as divided dose and avoided at night to prevent insomnia)
sick days
- unwell/trauma/surgery: double steroid dose for at least a week
- vomiting: replace oral with IM
Addisonian crisis causes
bilateral adrenal haemorrhage, suddenly stopping long-term steroids, illness/trauma/surgery in those with primary adrenal failure
Addisonian crisis presentation
shock, weakness, reduced GCS (confusion/coma), hypoglycaemia
Addisonian crisis diagnosis
FBC, UEs, glucose, cortisol, ACTH, lactate, cultures
Addisonian crisis management
ABCDE, fluid resuscitation, IV hydrocortisone (100mg STAT), correct electrolyte imbalances, IV glucose infusion
what is bilateral adrenal hyperplasia
congenital form of primary adrenal insufficiency
bilateral adrenal hyperplasia causes
develops due to mutation in 21 alpha hydroxylase enzyme which results in reduced aldosterone, reduced cortisol and increased androgen (due to increased ACTH as result of reduced cortisol)
bilateral adrenal hyperplasia presentation in children
- dehydration
- salt crisis
- failure to thrive
- girls: ambiguous genitalia
- boys: early virilisation, adrenal mass
bilateral adrenal hyperplasia presentation in adults
- females: hirsutism, oligomenorrhoea, reduced stature, acne
- males: acne, short stature, precocious puberty, early virilisation
bilateral adrenal hyperplasia diagnosis
- bloods: low sodium, high potassium, low glucose
- diagnostic: short synacthen test
- give synthetic ACTH: cortisol should increase (normal)
- measure cortisol before and then 30-60mins after
- normal results: baseline >170, 30-mins >550
- chest x-ray
- CT CAP
- auto-antibody screen
- plasma renin and aldosterone
- morning ACTH: high
bilateral adrenal hyperplasia management
- steroid replacement (fludrocortisone and hydrocortisone)
- female children: karyotyping and gender assignment
what is secondary adrenal insufficiency
failure to produce adequate steroids as a result of ACTH deficiency
secondary adrenal insufficiency causes
- pituitary disease
- long term, excessive steroid use (develops due to high levels of synthetic steroid dampening down steroid axis)
- only corticosteroid production is reduced, mineralocorticoid production is maintained (meaning low cortisol and normal aldosterone)
- insufficiency will only become apparent following withdrawal from steroids
secondary adrenal insufficiency presentation
- myalgia, arthralgia
- dizziness, weakness
- depression, psychosis
- abdominal pain, diarrhoea, vomiting
- lethargy, weight loss, hypoglycaemia, hypotension
- vitiligo
- postural hypotension
secondary adrenal insufficiency diagnosis
- short synacthen test
- morning ACTH is low
secondary adrenal hyperplasia management
oral hydrocortisone
what is primary hyperaldosteronism
excessive amounts of aldosterone independent of functions of RAAS
primary hyperaldosteronism causes
- idiopathic bilateral adrenal hyperplasia (most common)
- conn’s syndrome (aldosterone secreting adrenal adenoma)
primary hyperaldosteronism presentation
- polyuria
- polydipsia
- headaches
- weakness, cramps, paraesthesia, muscle spasms
- hypertension that is young onset and treatment resistant
primary hyperaldosteronism diagnosis
- bloods: high sodium, low potassium
- first line: plasma renin and aldosterone
- diagnostic
- plasma aldosterone: renin ratio > 750
- saline suppression test (failure to suppress aldosterone production by 50 following consumption of water)
- CT abdomen to identify adenoma (incidentaloma -> adrenal mass identified on CT with no clinical findings)
primary hyperaldosteronism management
- medical: aldosterone antagonist (spironolactone)
- surgical: removal of adenoma in conn’s
what is Cushing’s syndrome
umbrella term that describes symptoms caused by cortisol excess
what is Cushing’s disease
Cushing’s syndrome caused by caused by ACTH secreting pituitary tumour
Cushing’s syndrome endogenous causes
- ACTH dependent: pituitary adenoma, ectopic secretion (small cell lung cancer)
- ACTH independent: benign adrenal adenoma, malignant adrenal carcinoma
Cushing’s syndrome exogenous causes
prolonged steroid use
Cushing’s syndrome presentation
- central obesity, with striae
- moon face with facial plethora
- proximal muscle wasting (thin arms and legs, proximal myopathy so find standing up difficult)
- skin: loss of scalp hair, skin thinning, easy bruising, frontal male pattern baldness
- psychiatric: euphoria, depression, psychosis
- virilisation and hirsutism
- oligomenorrhoea or amenorrhoea
- medical conditions: hypertension, osteoporosis, hyperglycaemia, susceptibility to infection, poor wound healing, oligomenorrhoea, amenorrhoea
- ‘lemon on a stick’
- more prone to diabetes because cortisol is insulin antagonist
- skin is paper thin
Cushing’s syndrome diagnosis
- blood glucose: hyperglycaemia
- 24 hour urinary cortisol increased
- screening: overnight dexamethasone suppression test
- CT/MRI head
- CT CAP
- plasma ACTH
- hypokalaemic metabolic alkalosis
Cushing’s syndrome management
- iatrogenic: stop steroid
- pituitary or adrenal adenoma: surgical excision
- ectopic secretion: depends on site/extent of primary
- adrenal enzyme inhibitors
- metyrapone
- ketoconazole
what is a phaeochromocytoma
catecholamine producing tumours of the adrenal medulla, which predominately produce noradrenaline
phaeochromocytoma presentation
- headache
- palpitations
- sweating
- hypertension
- feeling of utter terror intermittently
- facial flushing
- shortness of breath
- chest tightness
- abdominal pain
phaeochromocytoma diagnosis
- 24 hour urinary collection of metanephrines
- MIBG scan (uses chromaffin seeking isotope)
phaeochromocytoma management
- surgical excision of tumour
- before surgery is carried out, blood pressure needs to be protected by alpha blockage (phenoxybenzamine) followed by beta blockage (atenolol)
