Hyperfunction Flashcards
Where is the origin of Cushing’s Disease?
Pituitary gland
Where is the origin of Cushing’s syndrome?
Anywhere except the pituitary gland
What is an exogenous cause of Cushing’s? Is this ACTH dependent or independent?
Iatrogenic (overuse of steroids)- ACTH independent
What are two endogenous causes of Cushing’s which are ACTH dependent?
ACTH producing pituitary adenoma, ectopic ACTH production
What is the main cause of ectopic ACTH production?
Carcinoid tumours
What are two endogenous causes of Cushing’s which are ACTH independent?
Adrenal tumours, non-lesional adrenal gland atrophies
Cushing’s syndrome is excess production of what hormone?
Cortisol
Who is Cushing’s syndrome most common in?
Women aged 20-40
What are 4 common clinical features of Cushing’s?
Easy bruising, facial plethora, striae, proximal myopathy
What eye problem does Cushing’s cause?
Cataracts
What does Cushing’s do to BP?
Raised
What effects does Cushing’s have on bone?
Osteoporosis and increased risk of avascular necrosis
What will the levels of ACTH be in Cushing’s caused by a pituitary adenoma, or ectopic?
High ACTH
What will the levels of ACTH be in Cushing’s caused by an adrenal adenoma or exogenous steroids?
Low ACTH
Give 3 examples of screening tests for Cushing’s?
Overnight dexamethasone suppression test, 24h urinary cortisol, late night salivary cortisol
What is the main diagnostic test for Cushing’s?
Low dose dexamethasone suppression test
What is the commonest cause of cortisol excess?
Iatrogenic Cushing’s due to prolonged use of (usually oral) high dose steroid treatment
What are two end results of long term steroid use?
Chronic suppression of pituitary ACTH production and adrenal atrophy
When should you investigate for a cause of secondary hypertension?
If the patient presents young or there is high clinical suspicion
What is primary hyperaldosteronism?
Autonomous production of aldosterone, independent of its regulators
What regulates aldosterone production?
K+ and angiotensin II
What is the commonest cause of secondary hypertension?
Primary aldosteronism
What features characterise primary aldosteronism?
Hypertension, periodic muscle weakness/paralysis, nocturia and polyuria
What happens to levels of potassium in primary aldosteronism? What can this result in?
Hypokalaemia, may cause metabolic alkalosis
What happens to levels of renin and aldosterone in primary aldosteronism?
High aldosterone, low renin
Aldosterone has many CV actions. What are the end points of this in primary aldosteronism?
Hypertension, left ventricular hypertrophy and atheroma
What is Conn’s Syndrome?
Primary aldosteronism caused by an adrenal adenoma
What is the commonest cause of primary aldosteronism?
Bilateral adrenal hyperplasia
What are some rare causes of primary aldosteronism?
Genetic defects and unilateral hyperplasia
What is the suppression test used for primary aldosteronism?
Saline suppression test
Explain the saline suppression test?
Failure of plasma aldosterone to suppress by > 50% with 2l of normal saline confirms the diagnosis
How can you confirm the subtype of primary aldosteronism?
Adrenal CT and adrenal vein sampling
What is the management for primary aldosteronism caused by an adrenal adenoma (Conn’s Syndrome)?
Unilateral laparoscopic adrenalectomy
What are the results of an adrenalectomy in a patient with Conn’s Syndrome?
Cures hypokalaemia and often hypertension
What is the treatment for primary aldosteronism caused by bilateral adrenal hyperplasia?
Mineralocorticoid antagonist (spironolactone)
