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IM Endo Adrenal USMLE 2


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Another name for Primary Adrenal insufficiency
Addison's Dz
shock, dehydration, confusion, vomiting, hyperK and Hypoglycemia

What are the (3) causes?
Addisonian (or adrenal) crisis

(2) main causes of Addison's Dz
Autoimmune (80%);

TB (15%)
MCC of Secondary adrenal insufficiency

(2) other causes
Exogenous steroid drugs

Sheehan's syndrome;
Pituitary infarct
How is Aldosterone made?

(2) functions
Angiotensin II acts on the zona glomerulosa to convert cortisone to aldosterone

Increase sodium reabsorption;
secretion of K+ and H+
What does a deficiency in aldosterone cause w/ electrolytes?

18-yo man w/ hemophilia A who was recently mugged (receiving multiple blows to head and abdomen) is now complaining of dizziness, abdominal pain, dark patches on his elbows and knees, and uncontrollable cravings for pizza and french fries
Primary Adrenal Insufficiency
(Addison's Dz)
How is secondary insufficiency distinguished from Addison's Dz?
No hyperpigmentation;

Normal aldosterone secretion;

Signs of hypopituitarism
(hypothyroidism or hypogonadism)
What is Cortisol's relation to glucose?
Stimulates gluconeogenesis by increasing protein and fat catabolism;

Decreases utilization of glucose and sensitivity to insulin
How does cortisol promote an anti-inflammatory state?
Inhibits Arachidonic Acid;

Inhibits IL-2 production;

Inhibits release of histamine from Mast cells
Hemorrhagic necrosis of the adrenal medulla during the course of meningococcemia
Waterhouse-Friderichsen Syndrome
hyperpigmentation, salt cravings, orthostatic hypotension, amenorrhea
Addison's Dz
(primary adrenal insufficiency)
Describe the ACTH (Cortrosyn) test to Dx Adrenal insufficiency etiology

How does it distinguish b/t primary and secondary?
Give ACTH and measure at zero and 30 minutes.
A level of < 18 at 30 = adrenal insufficiency

Measure plasma ACTH after test:
Primary = high ACTH
Secondary = low ACTH
Tx for adrenal insufficiency

what additional Tx for Addison's only?
Glucocorticoid replacement
(especially at times of stress)

additional for Addisons:
Mineralcorticoid replacement
What disease presents with the exact opposite of Addison's?
Cushing's Dz
Symptoms of excess Cortisol production
Cushing's syndrome
Cushing's syndrome caused by excess ACTH secretion of pituitary
Cushing's disease
What lung cancer is associated w/ ectopic ACTH production?
Small (Oat) cell lung CA
Etiology of Cushing's syndrome (Adrenal excess)
Exogenous corticosteroid therapy;

Adrenal neoplasm;

Ectopic ACTH production
HTN, hair loss, central obesity, hump on the back of neck, abdominal purplish striae, hirsuitism, proximal muscle weakness, osteoporosis
Cushing's syndrome
How is the ectopic ACTH Sx different from the ACTH Sx released directly from the adrenals?
Ectopic ACTH Sx:
Weight gain and proximal muscle weakness only

B/c: the ACTH in ectopic from is usually the inactive form.
How can Cushing's Dz be distinguished from Cushing's Syndrome?
Cushing's Dz:

presence of Hyperpigmentation
42-yo woman on long-term steroids for asthma has excess adipose tissue in her neck and upper trunk, a wide "moon face", and very fine hair
Cushing's Syndrome
(2) main lab tests to Dx Cushing's Syndrome

which is more specific as to finding the etiology?
Overnight Dexamethasone Suppression test

High-Dose Dexamethasone Suppression test
(more specific)
Describe the Overnight Dexamethasone test
1 mg of dexamethasone is given at night, then plasma cortisol is measured in the morning.

if < 5ug/100mL, it EXCLUDES Cushing's as the Dx
What are the 3 Dx from Dexamethasone Suppression test & ACTH that follows?
(3 results from test)
Give 8 mg dexamethasone, then measure ACTH:

1. If ACTH is decreased or undetectable w/ no supression =
Adrenal etiology

2. ACTH is Normal or Increased w/ no supression =
Ectopic ACTH etiology

3. ACTH is High w/ partial supression = Pituitary etiology
What are the electrolyte (Cl, K and Na) findings w/ Cushing's syndrome?

What is found in urine?



In Urine:
24-hour Urinary free cortisol > 100 ug/24hr
Tx of Cushing's from Pituitary adenomas
Transsphenoidal surgery

(radiation for children and refractory to surgery)
Tx of Cushing's from Adrenal Adenoma
Unilateral resection, followed by 3 to 12 months of glucocorticoid replacement
(until normal adrenal comes out of suppression)
Tx of Cushing's from Bilateral Adrenal Hyperplasia
Bilateral resection and lifelong replacements of glucocorticoids and mineralcorticoids
Tx of Cushing's from Ectopic ACTH production
Remove source of neoplasm
Isolated excess production of Aldosterone

- Another name for it?

"Conn's syndrome"
Etiology of Conn's syndrome

Which is MCC?
1. Unilateral aldosterone-producing Adenoma

2. Bilateral hyperplasia of Zona Glomerulosa
HTN, signs of HyperK (muscle cramps, palpitations), signs of glucose intolerance (polyuria, polydipsia); may also be asymptomatic
Conn's syndrome
Dx test for Conn's syndrome
Measure plasma aldosterone to plasma renin activity ratio

a ratio > 20 = Conn's syndrome (hyperaldosteronism)
44-yo woman has HTN, muscle cramps and excessive thirst

(Conn's syndrome)
What is the Tx for Conn's syndrome if it is due to hyperplasia?
1. Spirolactone or ACEi to control BP

2. Low-sodium diet
tumor of the adrenal medulla resulting in the intermittent release of catecholamine excess
(4) Disease Etiologies of Pheochromocytomas
(Pheochromocytoma, PTH tumor, medullary thyroid CA);

(Pheochromocytoma, PTH tumor, mucosal Neuromas);


Von Hippel-Lindau Dz
Pheochromocytoma, retinal angioma, CNS hemangioblastomas, renal cell CA, pancreatic pseudocysts, ependymal cystenoma
Von Hippel-Lindau Dz
38-yo woman on labetalol presents w/ poorly controlled hypertension, frequent headaches and palpitations
what are the 5 "H" Sx of pheochromocytoma?
Hot (diaphoretic);
Heart palpitations;
Hyperhidrosis (hand sweating)
Dx test for Pheochromocytoma
Elevated urine Vanillylmandelic Acid
(urine catecholamines)
Tx for pheochromocytoma
Surgical resection of mass;

Alpha-adrenergic blocker
(may also add B-blocker)
What is a possible misdiagnosis of Pheochromocytoma?
Anxiety disorder
What Dx is known for the "Rule of 10s":
10% are extra-adrenal; 10% are bilateral; 10% are malignant; 10% are familial; 10% are pediatric; 10% calcify; 10% recur after resection

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