Adrenal Disease Flashcards
Describe the cortex of the adrenal gland?
- Glomerulosa: Makes mineralocorticoids e.g. aldosterone.
- Fasiculata: Makes glucocorticoid e.g. cortisol.
- Reticularis: Makes androgens e.g. DHEA
Describe the medulla of the adrenal gland?
Produces catecholamines e.g. adrenaline (80%) and noradrenaline (20%).
What is the function of aldosterone?
Causes Na+ retention and K+ secretion via ENac and Na/K+ ATPase.
What regulates aldosterone production?
The RAAS
How is cortisol production regulated?
Hypothalamus produces corticotropin releasing hormone (CRH)
Anterior pituitary releases Adrenocorticotropic hormone (ACTH)
Adrenal cortex produces Cortisol.
Cortisol has negative feedback to both the hypothalamus and pituitary.
What would these blood results indicate?
High aldosterone
Low Renin
High ARR
Primary aldosteronism
What should the normal aldosterone-renin-ratio be?
<35
What medications should be stopped in primary aldosteronism?
- B blockers and MR antagonists
What investigations would you do to confirm primary aldosteronism?
A Saline Suppression Test
- Give 2L of saline over 4h
- 4h aldosterone >270 is
CT imaging to look for an adrenal adenoma.
How is primary aldosteronism managed?
Surgically
- Laproscopic adrenalectomy of an adrenal adenoma.
- Cures hypokalemia and hypertension
Medical
- Use MR antagonists
- e.g. Spironolocatone
What are some clinical features of Cushing’s syndrome?
Buffalo hump Striae Central obesity Proximal myopathy Poor would healing/easy bruising Thin skin Hypertension Moon face with plethoric cheeks.
What causes cushings syndrome?
Elevated cortisol
How do we test for elevated cortisol?
Perform 2 of …
- 24h Urinary free cortisol
- Urine cortisol:creatinine ratio x3
- Dexamethasone suppression test: Give high steroid at night and in the morning should be undetectable.
- Late night salivary cortisol: Should be low at night as cortisol has diurnal variation.
List causes of ACTH dependent cushings syndrome?
Pituitary adenoma (cushings disease)
Ectopic ACTH
Ectopic CRH
List causes of ACTH independent cushings syndrome?
Adrenal adenoma
Adrenal carcinoma
Nodular hyperplasia
How is congenital adrenal hyperplasia inherited?
Autosomal recessive disorder
What gene is most commonly affected in congenital adrenal hyperplasia?
CYP21 coding for 21-alpha hydroxylase
What are the clinical features of CDH in females?
Ambiguous genitalia
What are the clinical features of CAH in males?
- Adrenal crisis (hypotension, hyponatraemia)
- Early virilisation
How is CAH treated?
Mineralocorticoid and glucocorticoid replacement
What is pheochromocytoma?
Increased catecholamines due to a tumor of adrenal medulla or due to extra-adrenal tumors secreting catecholamine e.g. sympathetic ganglia.
What are the signs and symptoms of phaeochromocytoma?
- Hypertension
- headache
- palpitations
- pallor
- sweating
- tremor
- anxiety
- nausea, vomiting
- chest or abdo pain
- Normally have crisis of 15 minutes but in between feel well otherwise.
What genetic conditions are associated with pheochromocytoma?
MEN
Neurofibromastosis
Are most phaechromocytomas malignant or benign?
Benign
What imaging test are used to see adrenal glands?
CT ot MRI
Give examples of primary adrenal insufficiency?
Addisons disease
Autoimmune destruction
What are the clinical features of adrenal insufficiency?
- weight loss
- fatigue
- dizzy and low BP
- abdo pain, vomiting, diarrheoa
- skin pigmentation
How is adrenal insufficiency diagnosed?
- Biochemistry: Low sodium, high potassium, hypoglycemia
- Short synACTHen test: measure plasma cortisol before, and 30 mins after an IV ACTH injection. Normally >250 baseline and >480 post ACTH.
- High renin, low aldosterone
- May have adrenal autoantibodies.
What causes skin pigmentation in Addison’s disease?
High ACTH
What imaging should be used for the pituitary gland?
MRI
