Andrenals Flashcards
What is the best screening method for phaeochromocytoma’?
Urinary total catecholamine level
Metanephrines + Vanilyl mandedic acid
What is phaeochromocytoma’ derived from?
Neural crest cells
What is the most common cause of Cushing’s syndrome?
Steroid administration
What is Cushing’s disease ?
Primary pituitary disease - adenoma ACTH hypersecreation
What is the cause of Conns syndrome?
Excessive production of aldosterone
What are the characteristics of Conns syndrome?
- HTN
- Renal damage
- Hypokalemic alkalosis
- Muscle weakness
What are the causes of Conns syndrome?
- Adenoma of zona glomerulosa
2. Idiopathic bilateral hyperplasia of zona glomerulosa
Primary hyperaldosteronism?
- Conn syndrome
Secondary hyperaldosteronism ?
(Associated with increased levels of hormones of the RAA system)
- Following dehydration
- Blood loss
- Cardiac and liver failure with 3rd spacing of fluid
- Renal artery stenosis
What are the principle causes of adrenal insufficiency ?
- Autoimmune adrenalitis
2. TB of adrenal glands
What is the most common cause of congenital adrenal hyperplasia?
21-hydroxylase deficiency
What drugs are given prior to surgery for phaeochromocytoma?
- Alpha blockade - phEnoxybenzamine
2. Beta blockade
What is Addison’s disease?
Adrenal insufficiency
Ectopic ACTH
- Oat cell carcinoma
- Bronchial carcinoma
- Bronchial adenoma
- Thymic tumours
- Islet cell tumours
- MTC
Mineralocorticoid excess
- Increase BP due to sodium and water retention
- Tiredness
- Muscle weakness
- Thirst
- Polyuria/noctuira
- Headache
Diagnosing mineralocorticoid excess
- Increase aldosterone
- Increase sodium
- Decrease potassium (QT prolongation and U wave)
- Decrease plasma renin (due to negative feedback caused by increase BP and aldosterone)
Glucocorticoid excess
- Plasma cortisol levels - increase with loss of diurnal variation
- 24hr cortisol levels
- Dexamethasone suppression test (no decrease in morning cortisol levels)
- Plasma ACTH levels
Undetectable - primary adrenocortical tumours
Levels will be suppressed after administration of CRH in Cushing’s disease (but not if ACTH is ectopic)
Addison’s disease
Adrenocortical hypofunction
- AI
- Withdrawal of corticosteroid tx
- Post adrenelectomy
- Drugs - ketoconazole, rifampicin, phenytoin
- Infection - tb, hiv
- Sarcoid
- Water house fredrichson syndrome
- Metastatic deposits
- Amyloidosis
- CAH
- Panhypopituitarysm
- ACTH deficiency
Addison’s diagnostics
- Low sodium
- Low cortisol
- High ACTH
- Short synacthen test - no increase in cortisol
Acute Addison’s
- Low BP
- Hypoglycaemia
- Low sodium
- Dehydration
Chronic Addison’s
- Anorexia
- Decrease postural BP (due to Na and water loss)
- WL
- Muscle wasting
- Circumural skin pigmentation (b/c ACTH)
