Adrenal stuff

Question 1

How to diagnose Cushings?

Answer 1

(1) demonstrate cortisol excess
- overnight dexamethasone suppression test
- diurnal cortisol levels
- 24hr urinary free cortisol

Question 2

How to determine cause in Cushings?

Answer 2

• ACTH suppressed in adrenal Cushings
• ACTH normal/high in ACTH dependent Cushings

(1) high dose dexamethasone to determine cause (pituitary or ectopic ACTH)
–> pituitary - decreased in cortisol
Ectopic - no change to cortisol

(2) CRH test
- bushings - brisk response - Increased ACTH
- Ectopic ACTH - fairly flat

Question 3

Cushings disease treatment (pituitary)

Answer 3

• trans-sphenoidal hypophysectomy
• adrenelectomy & pituitary radiotherapy
• adrenal synthesis inhibitors (metyrapone, ketoconazole)
• somatostatin analogues - pasireotide

Question 4

Treatment for Cushings adrenal

Answer 4

laparoscopic adrenelectomy

Question 5

Treatment for Cushings - ectopic ACTH

Answer 5

• resection of tumour (typically bronchial carcinoid)

- medical therapy

Question 6

What are the causes of adrenal insufficiency?

Answer 6

Primary (Addison’s disease)
- lack of glucocorticoids and mineralocorticoids

Secondary (hypopituitarism)

• lack of ACTH and glucocorticoids
• normal mineralocorticoids

Question 7

What are some causes of Addisons?

Answer 7

• Autoimmune (80%)
• infections (HIV/TB)
• congenital
• surgery
• metastases
• amyloid
• hemorrhage

Question 8

How to tell the difference in primary vs secondary adrenal insufficiency based on symptoms?

Answer 8

Both: weakness, tiredness, fatigue, anorexia, nausea, vomiting, weight loss

Primary: Hyperpigmentation, postural hypotension +++, vitiligo and other autoimmune conditions

Secondary: hypopigmentation, postural hypotension, other hypopituitarism symptoms and signs

Question 9

How to diagnose adrenal insufficiency?

Answer 9

• Measure ACTH
• Short synACTHen test (synthetic ACTH IM)
  Primary
• measure U&Es, renin and aldosterone (renin would be high, aldosterone low), adrenal antibodies)
  Secondary
• investigate as for pituitary disease (anterior pituitary function test and MRI pituitary)

Question 10

What is the treatment for adrenal insufficiency - emergency and maintenance?

Answer 10

Emergency: IV access +2-3L saline with monitoring of volume status. Hydrocortisone 100mg IV 6 hourly.
Maintenance:
- hydrocortisone 10-15mg on waking
- hydrocortisone - 5-10mg evening
- Fludrocortisone - 0.05-0.1mg/day

Question 11

Three causes of endocrine hypertension?

Answer 11

(1) excess aldosterone from zona glomerulosa
(2) cortisol or precursors from zona fasciculata
(3) catecholamines from medulla

Question 12

What is the renin-angiotensin system?

Answer 12

Juxtaglomerular cells release renin.
Renin cleaves angiotensinogen to angiotensin 1.
ACE converts this to angiotensin 2 (causes vasoconstriction).
Angiotensin 2 acts on cortex (ZG) to release aldosterone.
Aldosterone acts on MR to increase BP, Na retention, K wasting. –> metabolic alkalosis

Question 13

What activated renin secretion?

Answer 13

• JG cell baroreceptors detect reduced ECF and renal perfusion pressure
• Macula densa: low plasma Na (low osmolality)
• Carotid arch baroreceptors: low arterial pressure (reduced ECF, cardiac output and vascular tone)
• -> all activate sympathetic innervation of JG apparatus

Question 14

What is Conn’s syndrome?

- phenotype, treatment

Answer 14

• unilateral adrenal tumour / aldosterone producing adenoma

Phenotype
- high plasma aldosterone, high Na
- low plasma renin, low K
- ECF expansion, hypertension
SAME AS BILATERAL ADRENAL HYPERPLASIA

Treatment = surgical

• venous sampling and/or CT scan
• unilateral adrenalectomy

Question 15

What is bilateral adrenal hyperplasia?

Answer 15

• idiopathic bilateral hyperplasia. 60-70% of PA

Phenotype
- high plasma aldosterone, high Na
- low plasma renin, low K
- ECF expansion, hypertension
SAME AS CONN'S SYNDROME

Treatment - pharmacological
- anti-hypertensives e.g. MR blockers
spironolactone, eplerenone