Adrenals Flashcards
What are the zones of the adrenal glands and what is secreted from each area?
Cortex:
- Glomerulosa: Mineralocorticoids
- Fasciculata- glucocorticoids
- Reticularis- sex steroids
Medulla: catecholamines: noradrenaline and adrenaline
What is primary hyperaldosteronism?
What happens to Na+ and K+ levels?
- Autonomous aldosterone overproduction from adrenal gland with subsequent suppression of plasma renin activity.
- Excess Na+ and water retention
- Increased renal K+ loss: hypokalaemia.
Give 3 causes of primary hyperaldosteronism.
- Adrenal adenoma: Conn’s syndrome- 70%
- Bilateral adrenal cortex hyperplasia- 30%
- Familial hyperaldosteronism
Rarely aldosterone producing adrenal carcinoma.
Give the epidemiology of Conn’s syndrome and Bilateral adrenal hyperplasia.
Conn’s: young females
BAH: older males
Primary hyperaldosteronism is 1-2% of hypertensive patients
Give 5 symptoms of hypokalaemia (due to primary hyperaldosteronism)
- Headaches, tiredness
- Polyuria, nocturia
- Muscle weakness, paraesthesia
Give the main clinical sign of primary hyperaldosteronism.
Give 2 complications of this.
- Hypertension which is difficult to control with antihypertensive medications
- Complications of hypertension include retinopathy, headaches.
Give 4 investigations for primary hyperaldosteronism.
- Salt loading: failure of aldo suppression post salt load confirms 1’ hyperaldosteronsim
- Postural test: patient upright for 4 hours: aldosterone adenoma decreases aldosterone production. BAH- adrenals respond to standing posture, increase renin production, leading to increased aldosterone.
- Fludrocortisone suppression test
- Bilateral adrenal vein catheterisation- elevated aldo in 1 vein indicates Conn’s (lateralisation). BAH is bilateral.
Give management for adrenal adenoma.
Give management for Bilateral adrenal hyperplasia.
Adrenalectomy- laproscopic.
BAH/ non-surgical candidates-
- Spironolactone (aldosterone inhibitor)- eplerenone if side effects not tolerated.
- Monitor K+, creatinine and BP.
Spironolactone side effects: gynaecomastia, impotence, muscle cramps
Give most common cause of exogenous Cushing’s syndrome.
Give 2 endogenous types of Cushing’s syndrome.
Exogenous: steroid exposure is most common cause.
Endogenous:
- ACTH- dependent (80%):
Excess ACTH from pituitary adenoma- Cushing’s disease.
Ectopic ACTH: e.g. lung tumour, pulmonary carcinoid tumour.
- ACTH- independent (20%):
Benign adrenal adenoma
Bilateral adrenal hyperplasia
Adrenal carcinoma: rare.
Give the epidemiology of Cushing’s syndrome for gender and age.
W:M 4:1
Age 20-40.
Give as many signs of Cushing’s syndrome as you can (11).
- Moon face + facial plethora
- Interscapular fat pad- “buffalo hump”
- Proximal muscle weakness
- Central obesity
- Pink/ purple stripe on abdomen/ breast/ thighs
- Easy bruising
- Kyphosis due to vertebral fracture
- Fractures
- Hypertension
- Ankle oedema: water retention from mineralocorticoid effect of excess cortisol
- Pigmentation in ACTH dependent cases
Give 2 first line high sensitivity tests for patients with a high-pre test probability for Cushing’s syndrome.
Give 2 investigations for differential diagnoses.
Overnight dexamethasone suppression test- dex at 11pm, measure cortisol at 8 am.
Low dose dexamethasone suppression test: small doses every 6 hours for 48 hours. Cortisol at 9am, 6 hrs after last dose.
Positive test is morning cortisol >50nanomol/L
- Serum glucose- high risk diabetes
- Pregnancy test
Give 4 tests to identify ACTH dependent Cushing’s syndrome
- Plasma ACTH
- Pituitary MRI
- High dose dex supp. test: differentiates CD and CS
- Inferior petrosal sinus sampling: test for ACTH conc. leaving sinus. > 2x baseline conc. = pituitary cause.
What is the medical treatment for Cushing’s syndrome?
What is the preferred treatment for Cushing’s syndrome?
What is treatment for persistent post-operative high cortisol?
What is Nelson’s syndrome?
- Metyrapone/ ketoconazole: inhibit cortisol synth.
- Surgical is preferred treatment.
Trans-sphenoidal resection of adenoma or surgery to remove adrenal adenoma/ carcinoma or ectopic ACTH. - Radiotherapy for persistent post-op. high cortisol.
Bilateral adrenalectomy may be complicated by Nelson’s syndrome: locally aggressive pit. tumour causing skin pigmentation.
Give 4 complications of Cushing’s syndrome
- Diabetes
- Osteoposis
- Hypertension
- Pre-disposition to infections: steroids are immunosuppressants.
If untreated, 5yr survival rate is 50%.
What is pheochromocytoma?
- Tumour from chromatin cells of adrenal medulla producing catecholamines.
- 10% bilateral
- 10% malignant
- 10% extra-adrenal: paragangliomas
Give 3 presenting symptoms of pheochromocytoma.
Give 3 other clinical signs.
Paroxysmal attacks of PHE:
- Palpitations
- Headaches
- Episodic sweating
- Hypertension
- Tachycardia
- Weight loss
- Fever
- Paleness of face
What patients should you consider phaeochromocytoma in?
Give 3 familial syndromes causing phaeochromocytoma.
- Consider in patients with young onset or resistant intractable hypertension.
- MEN2
- Von Hippel Lindau syndrome
- Neurofibromatosis type 1
Give 3 investigations for phaeochromocytoma
Give 2 imaging tests for tumour localisation.
- 24 hr urine collection- check for catecholamines, metanephrines and normetanephrines
- Plasma free metanephrines/ normetanephrines
- Genetic testing
CT> MRI
I-123 MIBG scintigraphy: similar structure to noradrenaline: incorporated into neurosecretory granules of phaeo: expensive, radioactive substance.
What percentage of adrenal cortex needs to be destroyed to result in adrenal insufficiency?
What is name for primary adrenal insufficiency?
90%
- Addison’s disease
Most common causes of adrenal insufficiency are iatrogenic, primary causes are rare.
Give two causes of iatrogenic adrenal insufficiency.
- Sudden cessation of long-term steroid therapy
- Post bilateral adrenalectomy.
Give 4 signs of Adrenal insufficiency.
- Increased pigmentation
- Postural hypotension
- Loss of body hair in women: androgen deficiency
- Associated autoimmune condition e.g. vitiligo.
Give 5 signs of Addisonian crisis
- Hypotensive shock- major haemodynamic collapse.
- Tachycardia
- Pale
- Cold
- Clammy.
Give 2 investigations to confirm diagnosis of adrenal insufficiency.
Give 3 investigations to identify cause of adrenal insufficiency.
- 9am serum cortisol less than 100nmol/L
- Short SynACTHen test: serum cortisol <550nmol after 30 mins.
- Long SynACTHen test
- Autoantibodies
- Abdo CT/ MRI/.
