TBL Prep Flashcards
What are some endocrine causes of secondary HTN?
primary aldosteronism-pretty common, may present with hypokalemia
pheochromocytoma
Cushing’s disease
What are some differences in presentation in secondary HTN that can help distinguish it from essential HTN?
abrupt onset greater severity absent fhx any age of onset sometimes tachycardia & volume overload
What is a pheochromocytoma?
tumor of neuroectodermal origin that causes release of a bunch of catecholamines, raises BP
How common is pheochromocytoma as a cause of secondary HTN? People with which condition should be screened for it?
1% of cases of secondary HTN
screen patients with neurofibromatosis
What is the typical triad of symptoms of pheochromocytoma? Which other symptoms may be present?
triad–headache, excessive sweating, palpitations
other features–pallor, weight loss, anxiety
Give 3 possible patterns of BP elevation w/ pheochromocytoma.
- sustained HTN w/o BP spikes
- sustained HTN w/ BP spikes to a crisis level
- normotensive w/ BP spikes
Which symptom when seen with HTN should send off bells in your head for pheochromocytoma?
orthostatic hypotension
Which symptoms are seen with a pheochromocytoma-related HTN crisis?
dizziness flushing visual disturbances anxiety N/V epileptic aura
What are some other things that should be on the ddx for pheochromocytoma?
paroxysmal vasodilating headaches autonomic dysfunction anxiety acute hypoglycemia CAD cocaine
What are some lab tests that help in the diagnosis of pheochromocytoma?
urinary & plasma catecholamine measurements
urinary metanephrines
urinary vanillylmandelic acid
What used to be considered the most reliable lab test for pheochromocytoma? What is the most reliable one now?
Past–urinary assay of catecholamines
Current–plasma free metanephrines, most sensitive, even b/w spells of spilling out catecholamines
What is it about plasma free metanephrines that makes them so reliable even b/w “spells” with pheochromocytoma?
continuous production of O-methylated metabolites from catecholamines seeping from chromaffin stores in tumors
Which is better–measure only total metanephrines? Or measure fractionated too?
best to include fractionated too b/c some tumors release only one type
How can you distinguish false positives from true positives when testing for pheochromocytoma?
true pos. have catecholamines 2-3X normal high end of reference range.
If b/w 1000-2000 & hard to distinguish can use the clonidine suppression test
Abdominal CT or MRI also helpful sometimes
What is involved in the clonidine suppression test when diagnosing pheochromocytoma?
if the excess catecholamines are b/c of excess SNS the clonidine will decrease it.
If a pheochromocytoma–no real effect.
Describe the treatment for pheochromocytoma.
surgical removal (whether benign or malignant)
with alpha & beta blockers pre-op
volume attention (often volume depleted)
1 wk for symptoms to go away
often metastasizes or recurs–f/u important.
When do you usu see primary hyperaldosteronism?
30-50s
cause of resistant HTN in African Americans & Caucasians
Which symptoms pop up in primary hyperaldosteronism? When should you think about it as a possible diagnosis?
hypokalemia, metabolic alkalosis & refractory HTN
weakness
polyuria, polydipsia
nocturia
T/F Edema is a common feature of primary hyperaldosteronism b/c of the Na+ retention.
False. there are enough Na+ wasting forces counteracting it that it isn’t usu seen.
What are common complications of primary hyperaldosteronism?
LV hypertrophy–>heart failure
perhaps b/c aldosterone is pro-fibrotic & increases oxidative stress
Which conditions can mimic primary hyperaldosteronism?
licorice ingestion
Cushing’s syndrome
Liddle’s syndrome
Why could eating a bunch of licorice cause endocrine changes?
glycyrrhizic acid inhibits renal 11-beta-hydroxysteroid dehydrogenase (which metabolizes steroids)
now you have more active cortisol. Na+ retention & K+ loss.
Not all primary hyperaldosteronism patients exhibit hypokalemia…so what is the best test to check for it?
urinary aldosterone excretion after 3 days of salt loading
What is an appropriate screening test for primary hyperaldosteronism? When should this test be taken ideally?
Morning–when aldosterone is the highest
plasma aldosterone-renin ratio
Look for ratio>30
What are other tests to consider using in primary hyperaldosteronism?
plasma K+ levels 24-hour K+ excretion Plasma aldosterone-renin ratio fludrocortisone test CT adrenal vein sampling
What is the best treatment for a unilateral adrenal adenoma, causing primary hyperaldosteronism?
surgical resection
What is the best treatment for bilateral adrenal hyperplasia or adenomas?
medical management including: spironolactone eplerenone Diuretic Salt & H2O control other anti-HTN meds
What are the drawbacks of spironolactone?
can cause impotence & gynecomastia in high doses
eplerenone is also an aldosterone antagonist, but has fewer of these side effects
T/F Ca++ channel blockers are a good addition to medical management of primary hyperaldosteronism.
False. They don’t do anything to aldosterone.
What is the most common cause of ACTH-dependent Cushing’s syndrome?
Cushing’s disease–ACTH-secreting adenoma
messes w/ the adrenal gland–excess of cortisol.
What makes up the other cases of ACTH-dependent Cushing’s syndrome?
oat cell
small cell carcinoma of lung
carcinoid tumor of bronchus or thymus
WHat are some examples of ACTH-independent causes of Cushing’s syndrome?
adrenal adenoma
adrenal carcinoma
macro or micronodular hyperplasia
What is the most affected age group for Cushing’s syndrome? Is HTN a major feature?
HTN is a major feature b/c of excess cortisol
25-40
What is the usual presentation of Cushing’s syndrome?
moon facies buffalo hump abdominal fat striae proximal muscle weakness/fatigue HTN hirsutism easy bruising insulin resistance increased cardio risk prothrombotic state amenorrhea loss of libido osteoporosis
What is the presentation of patients with Cushing’s syndrome from excess ectopic ACTH secretion?
hyperpigmentation from too much POMC
severe HTN
hypokalemic metabolic alkalosis
WHat are 2 exogenous things that can look like true Cushing’s syndrome?
too much steroid use
chronic alcoholism
What is an appropriate screening test for Cushing’s?
dexamethasone suppression test
should drop cortisol to s
What is a good confirmatory test for cushing’s?
24 hour urinary free cortisol
-only a problem if renal failure
if>100–>cushing’s
What is the 5 year survival for Cushing’s? What is the surgical approach?
50% b/c of excess glucocorticoids
transsphenoidal approach to the pituitary
or adrenalectomy when approrpiate
Give some drugs used in the medical management of Cushing’s.
ketoconazole–good long term
mitotane–steroidogenesis inhibitor, adrenolytic
mifepristone–blocks glucocorticoid receptora ctivation
If you’re thinking about treating the HTN of a Cushing’s patient…what should you consider?
K+ sparing! spironolactone, amiloride
NOT loop diuretics
careful w/ beta blockers
Screening in HTN patients for endocrine abnormalities is really only high yield for what?
primary hyperaldosteronism
