Endocrinology - Clinical Flashcards
What syndrome results from hyperfunction of the adrenal gland?
Cushing syndrome
What causes Cushing syndrome?
Prolonged exposure to elevated levels of cortisol or exogenous glucocorticoid drugs
What other general features can be caused by excess cortisol?
1) Osteoporosis
2) Negative nitrogen balance
3) Increase appetite
4) Obesity
5) Increased susceptibility to infection
What is Cushing disease caused by?
A pituitary tumour producing excess ACTH
What are clinical features of Cushing?
- Obesity
- Hypertension
- Hirsutism
- Purple/red striae
- Acne
- Bruising due to thin skin
- Neuropsychiatric defects
- Menstrual disorders
- Impotence
- Glucose intolerance
- (Worsening) diabetes
- Fatigue
- Low mood
- Thin arms and legs (myopathy)
- Red cheeks
- Moon face
- Poor wound healing
- Distended abdomen
- Fat pads (buffalo hump)
What are possible causes of adrenal hyperfunction?
1) ACTH dependent - pituitary (Cushing’s)
2) ACTH independent - adrenal adenoma/carcinoma
3) Exogenous steroids
Why is Cushing’s syndrome hard to confirm?
Because it can’t be confirmed by one blood test - need 2 or 3 positives
Describe 3 tests used to confirm Cushing’s
1) Low dose dexamethasone suppression test - unsuppressed cortisol next morning → overproduction
2) 24h urinary cortisol
3) Loss of diurnal rhythm (mid night cortisol) - insert cannula before sleep and take sample when asleep → lack of change indicates under regulated production
What is an intervention treatment used to treat Cushing’s and describe it ?
Laparoscopic adrenalectomy
- Give replacement glucocorticoids (hydrocortisone) to prevent feeling like they have adrenal under function
- Many of the features improve → BP, diabetes but psychological disturbances may continue
What are the different modes of action for drug treatment for Cushing’s?
1) Inhibit steroid biosynthesis
2) Inhibit ACTH release
3) Inhibit glucocorticoid receptor
What medication is used to inhibit steroid biosynthesis to treat Cushing’s?
1) Metyrapone - 11β-hydroxylase inhibitor
2) Ketoconazone - 17α-hydroxylase and 11β-hydroxylase inhibitor
What medication is used to inhibit ACTH release to treat Cushing’s?
1) Pasireotide - SSTR5 (somatostatin analogue) agonist
2) Cabergoline - dopamine D2 agonist
What medication is used to inhibit the glucocorticoid receptor to treat Cushing’s?
Mifeprestone - also a progestogen receptor antagonist
What is pheochromocytoma?
Tumour of the adrenal medulla which secretes noradrenaline or adrenaline
Describe the presentation of pheochromocytoma
1) Headaches
2) Palpitations, heart racing
3) Sense of doom
4) Chest pain
5) Sweating
6) Weight loss
7) Episode of collapse
How do you diagnose pheochromocytoma?
24h urine catecholamines
How do you treat pheochromocytoma?
Surgical removal after pre-treatment with alpha and B blockade e.g. doxazosin
What are the signs and symptoms of hyperaldosteronism?
1) Resistant hypertension
2) Low K
3) Low renin
4) Elevated aldosterone
Describe primary hyperaldosteronism
1) Autonomous hypersecretion of aldosterone
2) Independent of RAS
3) Low/suppressed renin
What is an example of a primary hyperaldosteronism syndrome?
Conn’s syndrome - hypertension, hypokalaemia, alkalosis, unilateral adenoma
How do you confirm primary hyperaldosteronism?
1) Measurement of PRA (suppressed) and aldosteorne (high) in salt-replete individuals
2) Selective venous sampling
How do you treat Conn’s syndrome?
1) Remove the adenoma - laparoscopic
2) Drug treatment - spironolactone (aldosterone agonist, used as K sparing diuretic) or eplerenone
What disease is caused by hypofunction of the adrenal gland?
Addison’s disease