ChemPath: Adrenal Disease
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What are the five layers of the adrenal gland?
• Capsule • Glomerulosa • Fasciculata • Reticularis • Medulla
What can cause adrenal glands to appear wasted?
Addison’s disease Long-term steroid use
What can cause adrenal glands to become hyperplastic?
Cushing’s disease Ectopic ACTH
By what factor is the output of cortisol from the adrenals greater than the output of aldosterone?
About 1000 (aldosterone is measured in picomoles, cortisol is measured in nanomoles)
How many arteries and veins do the adrenal glands have?
57 small arteries 1 vein
How is a blood sample to measure adrenal output taken?
A cannula is placed through the IVC into the adrenal vein
How is the venous drainage different for the left and right adrenal glands?
Left - drains into the left renal vein Right - drains directly into the IVC
What condition includes both primary hypothyroidism and Addison’s disease?
Schmidt syndrome (though it is now called Polyglandular Autoimmune Syndrome Type 2)
Describe the short synacthen test.
• Measure cortisol and ACTH at the start of the test • Administer 250µg synthetic ACTH by IM injection • Check cortisol at 30 and 60 mins • Healthy people should produce >550nM of cortisol within 30 mins
What is the differential diagnosis for hypertension with an adrenal mass?
• Phaeochromocytoma • Conn’s syndrome • Cushing’s syndrome
What are the disastrous consequences of phaeochromocytoma?
• Severe hypertension • Arrhythmia • Death
Outline the treatment of phaeochromocytoma.
• Urgent alpha blockade (with phenoxybenzamine or phentolamine or doxazocin) • Some fluids may be given after the alpha-blocker to prevent reflex tachcardia • A beta-blocker should be given after the alpha-blocker to prevent reflex tachycardia • Patients should receive high-dose alpha and beta-blockade before surgery as the action of surgery can cause the release of catecholamines from the adrenals
Name three genetic syndromes associated with phaeochromocytomas.
• MEN2 • Von Hippel Lindau syndrome • Neurofibromatosis type 1
Describe the levels of aldosterone and renin in Conn’s syndrome.
High aldosterone Low renin
List some tests used in Cushing’s syndrome.
• 9am cortisol • Midnight cortisol • Low-dose dexamethasone suppression test • Inferior petrosal sinus sampling (determines whether high levels of ACTH are from pituitary or ectopic from somewhere else)
Describe how low-dose dexamethasone suppression test is performed.
• The patient’s baseline ACTH and cortisol is measured at the start • Then they are given 0.5mg dexamethasone every 6 hours for 48 hours • This should suppress cortisol to <50nM • inferior petrosal sinus sampling with CRH stimulation
What proportion of endogenous Cushing’s syndrome is caused by Cushing’s disease?
85%
What is pseudo-Cushing’s syndrome?
Obesity can change your metabolism of cortisol to produce a clinical syndrome that looks like Cushing’s syndrome
List three endogenous causes of Cushing’s syndrome.
Pituitary-dependent Cushing’s disease Adrenal adenoma Ectopic ACTH
What is this?
Adrenal Glands