Chapter 21: Adrenal Flashcards
vascular supply: superior adrenal
inferior phrenic artery
vascular supply: middle adrenal
aorta
vascular supply: inferior adrenal
renal artery
drainage of left adrenal vein
left renal vein
drainage of right adrenal vein
inferior vena cava
Innervation of medulla
sympathetic splanchnic nerve
innervation of adrenal cortex
no innervation of adrenal cortex
lymphatic drainage of adrenal
lymphatics drain to subdiaphragmatic and renal lymph nodes
what makes up the adrenals
made up of adrenal cortex and adrenal medulla
incidence of incidentaloma of adrenal mass on CT scan
1%-2% of abdominal CT scans show incidentaloma (5% are metastases)
two things to know about asymptomatic adrenal masses
- benign adenomas are common
- adrenals are also common site for metastases
what to do when you see an asymptomatic adrenal mass?
check for functioning tumor: urine metanephrines/vma/catecholamines, urinary hydroxycorticosteroids, serum K with plasma renin and aldosterone levels
- Consider CXR, colonoscopy, mammogram to check for a primary tumor
when is surgery indicated for asymptomatic adrenal mass?
ominous characteristics (non-homogenous), is > 4-6 cm, is functioning or is enlarging
how do you follow an incidentaloma?
need repeat imaging every 3 months for 1 year, then yearly
approach for adrenal CA resection
anterior approach for adrenal CA resection
Common metastases to adrenal
Lung CA (#1), breast CA, melanoma, renal CA
Management: cancer history with asymptomatic adrenal mass
Need biopsy
what if you have isolated metastases to the adrenal gland?
some isolated metastases to the adrenal gland can be resected with adrenalectomy
layers of the adrenal cortex
GFR = salt, sugar, sex steroids
- Glomerulosa: aldosterone
- Fasciculata: glucocorticoids
- Reticularis: androgens / estrogens
precursor for androgens / cortisol / aldosterone
cholesterol -> progesterone -> androgens/cortisol/aldosterone
what enzyme do all zones of the adrenal cortex contain?
all zones have 21- and 11-beta hydroxylase
Released from the hypothalamus and goes to anterior pituitary gland
Corticotropin-releasing hormone (CRH)
Released from the anterior pituitary gland and causes the release of cortisol
ACTH
Has a diurnal peak at 4-6 am
Cortisol
Inotropic, chronotropic, and increases vascular resistance; proteolysis and gluconeogenesis; decreases inflammation
Cortisol
Stimulates renal sodium resorption and secretion of potassium and hydrogen ion
Aldosterone
What stimulates aldosterone secretion?
Stimulates by angiotensin II and hyperkalmeia, and to some extent ACTH
What is significant of excess estrogens and androgens by adrenals?
Almost always cancer
Enzyme defect in cortisol synthesis
Congenital adrenal hyperplasia
- MCC congenital adrenal hyperplasia
- Precocious puberty in males
- Virilization in females
- Increased 17-OH progesterone leads to increased production of testosterone
- Is salt wasting (decreased sodium and increased potassium) and causes hypotension
21-hydroxylase deficiency (90%)
Tx: 21-hydroxylase deficiency
Cortisol, genitoplasty
HTN secondary to sodium retention without edema; hypokalemia; also have weakness, polydipsia, and polyuira
Hyperaldosteronism (Conn’s syndrome)
1 cause of primary hyperaldosteronism
Adenoma (85%)
Causes of primary hyperaldosteronism (Conn’s syndrome)
Adenoma (85%), hyperplasia (15%), ovarian tumors (rare), cancer (rare)
Causes of secondary hyperaldosteronism (Conn’s syndrome)
More common than primary disease
- CHF
- Renal artery stenosis
- Liver failure
- Bartter’s syndrome (renin-secreting tumor
Dx for primary hyperaldosteronism
- Salt load suppression test (best, urine aldosterone will stay high)
- Aldosterone:renin ratio > 20
- Labs: low K, high Na, high urine K, metabolic alkalosis
- Plasma renin activity will be low
Localizing studies for hyperaldosteronism (Conn’s syndrome)
MRI, NP-59 scintigraphy (shows hyper functioning adrenal tissue; differentiates adenoma from hyperplasia; 90% accurate); adrenal venous sampling if others nondiagnostic
What do you need to consider for pre-op optimization in hyperaldosteronism?
Pre-op need control of HTN and K replacement
Hyperaldosteronism: adenoma tx
Adrenalectomy
Hyperaldosteronism: hyperplasia treatment
Seldom cured (increased morbidity with bilateral resection)
- Try medial therapy first using spironolactone (inhibits aldosterone), calcium channel blockers, and potassium
- if bilateral resection is performed (usually done for refractory hypokalemia), patient will need fludrocortisone postoperatively
Adrenal insufficiency, Addison’s disease
Hypocortisolism
1 cause hypocortisolism
Withdrawal of exogenous steroids
1 primary disease: hypocortisolism
Autoimmune disease
Causes of hypocortisolism (Addison’s disease)
Withdrawal of exogenous steroids (#1), pituitary disease, adrenal infection / hemorrhage / metastasis / resection