Suprarenal (adrenal) Gland

Question 0

Half moon shape

Answer 0

Left suprarenal gland

Question 1

Pyramid shape

Answer 1

Right suprarenal gland

Question 2

Arterial supply

Answer 2

Inferior phrenic artery via SUPERIOR SUPRARENAL ARTERY

Aorta via MIDDLE SUPRARENAL ARTERY

Renal artery via INFERIOR SUPRARENAL ARTERY

Question 3

Venous drainage

Answer 3

Right suprarenal vein –> inferior vena cava

Left suprarenal vein –> left renal vein

Adrenalectomy: suprarenal vein must be ligated as soon as possible to prevent release of catecholamines

Adrenal medulla receives venous blood that drains from the cortex (high cortisol)

Synthesis of phenylethanolamine-N-methyltransferase (key enzyme in epinephrine synthesis) requires high levels of cortisol)

Question 4

Adrenal cortex

Answer 4

From mesoderm!

Question 5

3 zones

Answer 5

Zona Glomerulosa (15%)

• aldosterone
• renin-angiotensin system

Zona fasciculata (78%)

• cortisol
• CRF, ACTH

Zona reticularis (7%)

• dehydroepiandrosterone (DHEA) & androstenedione
• CRF, ACTH

Question 6

Cause:

• aldosterone-secreting adenoma (Conn’s disease)
• adrenal hyperplasia

SSX: hypertension, hypernatremia, weight gain (water retention), hypokalemia, ⬇️ plasma renin

Tx: surgery or Spironolactone

Answer 6

Primary hyperaldosteronism

Question 7

Cause:

• ACTH-secreting adenoma within adenohypophysis (70%)
• adrenal adenoma (25%)
• adrenal hyperplasia (5%)
• oat cell CA of the lung

SSX: mild hypertension, osteoporosis, impaired glucose tolerance

Tx: ketoconazole (inhibits steroid biosynthesis)

Answer 7

Cushing syndrome (hypercortisolism)

Question 8

21-hydroxylase deficiency (90%)

• No synthesis of aldosterone, cortisol
• Intermediates are funned into androgen biosynthesis

11-B-hydroxylase deficiency

Answer 8

Congenital adrenal hyperplasia (CAH)

Question 9

Cause: autoimmune destruction of adrenal cortex, adrenal tuberculosis, fungal infection, adrenal hemorrhage

SSX: fatigue, anorexia, weight loss, hypoglycemia, hypotension & skin hyperpigmentation (⬆️ MSH)

Tx: steroid replacement therapy

Answer 9

Primary adrenal insufficiency (Addison disease)

Question 10

Cause: hypothalamic or pituitary disorder causing ⬇️ ACTH
- MC cause: iatrogenic suppression of ACTH

SSX: similar to Addison disease but no skin hyperpigmentation

Tx: steroid replacement therapy

Answer 10

Secondary adrenal insufficiency

Question 11

Contains chromaffin cells (modified postganglionic sympathetic neurons derived from neural crest cells)

Preganglionic sympathetic axons (through splanchnic nerves) synapse on chromaffic cells causing catecholamine secretion
- 90% epinephrine & 10% norepinephrine

Answer 11

Adrenal medulla

Question 12

Usually benign, neural crest origin

Usually found in adrenal gland
- extra-adrenal sites: organ of Zuckerkandl (near the aortic bifurcation)

Associated with: MEN IIa
(Pheochromocytoma, hyperparathyroidism & medullary CA), Von Recklinghausen neurofibromatosis

SSX: persistent or paroxysmal hypertension, tremor, profuse sweating, pallor, chest & abdominal pain

Dx: ⬆️ urinary vanillylmandelic acid, metanephrinem hyperglycemia, inability to suppress catecholamine with clonidine

Tx: surgery or Phenoxybenzamine (a-adrenergic antagonist)

Answer 12

Pheochromocytoma

Question 13

Extra-adrenal neoplasm containing primitive neuroblast of neural crest origin

Site: along sympathetic chain ganglia (70%) or within adrenal medulla (40%)

Site of metastasis: bone marrow, liver, orbit

MC solid tumor in children

SSX: opsoclonus “dancing eyes” (rapid, irregular, horizontal & vertical eye movements)

Dx: small cells in Homer-Wright pseudorosettes, ⬆️ urinary vanillylmandelic acid & metanephrine

Tx: surgery excision, radiation & chemotherapy

Answer 13

Neuroblastoma