Adrenal Gland Flashcards
(46 cards)
What causes Cushing’s syndrome?
Excess cortisol
What is the commonest cause of Cushing’s?
Exogenous cortisol (high-dose steroid medications)
What causes exogenous Cushing’s?
Prolonged high-dose steroid medications cause negative feedback on the pituitary and hypothalamus (decrease CRH ACTH). Cortisol production is shut down but the exogenous production is still great enough to cause Cushing’s
What is Cushing’s disease?
Pituitary adenoma causing Cushing’s syndrome
What are the ACTH dependent causes of Cushing’s?
Pituitary adenoma (Cushing's disease) Ectopic ATCH (or CRH) due to tumour (carcinoma, carcinoid)
What are the ACTH independent causes of Cushing’s?
Adrenal adenoma or carcinoma
Nodular adrenal hyperplasia
Why does Cushing’s cause hyperglycaemia?
Cortisol excess can inhibit the uptake of glucose in the muscles causing hyperglycaemia and insulin resistance
What are the signs + symptoms of Cushing’s?
Muscle wasting, proximal myopathy Thin extremities Thin skin Easy bruising and poor wound healing Abdominal striae Osteoporosis (whereas in obesity you would get increased bone density) Buffalo hump Central obesity Hyperglycaemia Appearance change over time Diabetes mellitus Psychosis, depression Facial plethora (redness) Cataracts Interscapular and supraclavicular fat pats Chemosis
What are the signs + symptoms caused by excess aldosterone in Cushing’s?
Hypertension
Oedema
What are the signs + symptoms caused by excess androgen in Cushing’s?
Virilism Hirsutism Acne Oligomenorrhoea Amenorrhoea Female frontal balding Lack of libido and impotence
What screening tests are done to establish cortisol excess in Cushing’s?
Overnight dexamethasone suppression test (normally cortisol is suppressed)
24hr urinary free cortisol
Late night salivary cortisol
What is the gold standard/diagnostic test for Cushing’s syndrome and what result is considered abnormal?
Low dose dexamethasone suppression test (done after a positive overnight dexamethasone suppression test)
>130nmol/L = abnormal
<50nmol/L = no Cushing’s
50-130nmol/L = other tests to bes considered
What test can be used for Cushing’s disease?
Raised ACTH (can be pituitary adenoma or ectopic ACTH)
Raised ACTH and cortisol in response to exogenous CRH (ectopic sources rarely respond)
Pituitary MRI
How is exogenous Cushing’s treated?
Stop medication if possible
What are the treatment options for Cushing’s disease?
- Hypophysectomy (surgical removal of pituitary adenoma)
- External radiotherapy
- Medical therapy to reduce ACTH
- Bilateral adrenalectomy (last resort)
What are the treatment options for an adrenal (ACTH independent) cause of Cushing’s?
- Adrenalectomy
2. Radiotherapy + adrenolytic drugs
What are the treatment options for an ectopic (ACTH dependent) cause of Cushing’s?
- Adrenalectomy
2. Radiotherapy + adrenolytic drugs (if carcinoma)
What drug treatments are available for Cushing’s syndrome?
Metyrapone
Ketoconazole
Pasireotide LAR
What is primary hyperaldosteronism?
When the adrenal cortex produces excess aldosterone
What is the pathogenesis of primary hyperaldosteronism?
Autonomous production of aldosterone independent of its regulators
This leads to sodium retention and potassium loss resulting in hypokalaemia and hypertension
What are the causes/subtypes of primary hyperaldosteronism?
Bilateral adrenal hyperplasia Adrenal adenoma Adrenal carcinoma Genetic mutations Unilateral adrenal hyperplasia
What is the most common cause/subtype of primary hyperaldosteronism?
Bilateral adrenal hyperplasia
What is Conn’s syndrome?
Primary hyperaldosteronism caused by an adrenal adenoma
What mutation is Conn’s syndrome linked to?
Mutation in K+ channels (KCHNJ5 mutations)
