Adrenal Disorders for the USMLE

by / Tuesday, 03 August 2010 / Published in Internal Medicine

Adrenal Disorders

Cushing’s Syndrome

There are 3 sources of Cushing’s disease, they are listed in this table along with pertinent information

Pituitary Tumor Ectopic ACTH Production Adrenal Adenoma
ACTH High High Low
High-dose dexamethasone Suppression No suppression No suppression
Specific test MRI, petrosal vein sampling Scan the chest and abdomen Scan the adrenals
Treatment Removal Removal Removal

There is a common presentation of all patients with hypercortisolism:

  • Fat redistribution:  Truncal obesity, buffalo hump, thin arms/legs, “moon facies”
  • Striae and easy bruising: Due to a loss of collagen(cortisol thins the skin)
  • HTN: Due to fluid and sodium retention
  • Hirsuitism: from increased adrenal androgen levels
  • Muscle wasting


  1. 1mg overnight dexamethasone suppression test:  normally a person will suppress the 8am level of cortisol if given dexa at 11pm the previous night.  A normal test (suppression) will rule out hypercortisolism of all kinds.  ** a test may be elevated due to other factors such as depression, alcoholism, or excessive stress
  2. 24-hr urine cortisol:  this test adds specificity to the overnight dexamethasone test, if the overnight test was abnormal (failing to suppress ACTH), then this test confirms hypercortisolism.

** these tests are to diagnose the presence of Cushing’s syndrome, the location is still unknown at this point.

Diagnosing the location:

  • Looking at the ACTH can help identify the location
  • If ACTH is high – source of problem is the pituitary or ectopic ACTH production
  • If ACTH is low – source is the adrenal


  • Removal of whatever is causing the problem, identified by MRI or abdominal scan (depending on the location of the problem)

Addison’s Disease (adrenal insufficiency)

Can be primary (Addison’s) or secondary (Decr ACTH production from pituitary)

Addison’s disease:

  • MC is autoimmune disorder
  • Waterhouse-Friderichsen may be cause, which is hemorrhagic necrosis of the adrenal medulla during the course of meningococcemia

Signs and Symptoms:

  • Fatigue
  • Anorexia
  • Hyponatremia + hyperkalemia
  • Hypotension
  • Nausea/vomiting
  • Constipation
  • Hyperpigmentation (only in primary case)


  • Incr ACTH and Decr cortisol (in response to ACTH)
  • Hyperpigmentation
  • If cause is secondary, then cortisol will increase in response to ACTH


  • For acute Addison’s give fluids + hydrocortisone
  • For stable patient give prednisone
  • If patients do not respond to above treatments, give fludrocortisone (highest # of mineralocorticoids)

Adrenal Cortical Hyperfunction

1° Hyperaldosteronism (Conn’s Syndrome):

  • Most commonly due to an adenoma or hyperplasia of the zona glomerulosa of the adrenal gland

Signs and Symptoms:

  • Hypertension
  • Incr Na+
  • Incr Cl-
  • Decr K+
  • Decr renin


  • Incr aldosterone
  • Decr renin
  • CT showing adrenal lesion


  • If adenoma – surgical resection
  • If hyperplasia – spironolactone

2° Hyperaldosteronism:

  • Increased renin production 2° to decreased renal bloodflow(CHF, shock, renal artery stenosis)


  • Incr renin (this is used to differentiate between 1° and 2° causes)


  • Treat underlying cause
  • Treat HTN


Patient presents with:

  • Episodic HTN
  • Headache
  • Palpitations
  • Tachycardia
  • Diaphoresis


  • Best initial tests – high plasma and urinary catecholamine/plasma-free metanephrine and VMA levels
  • Most accurate tests – CT or MRI of adrenal glands


  • 1st – phenoxybenzamine to control BP
  • 2nd – propranolol (only after a-blockade with phenoxybenzamine)
  • 3rd – surgical resection

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