TBL Endocrine Flashcards
In what ways do secondary forms of hypertension, which are endocrine in origin differ from essential hypertension in which an etiology can be identified?
abrupt onset
greater severity
no positive family history of HTN
no specific age criterion
List 3 endocrine diseases that can cause secondary HTN
primary hyperaldosteronism
Cushing’s disease
pheochromocytoma
Explain the concept of pseudoresisitance
when medications cause tachycardia, volume expansion, and/or RAAS activation –> plasma volume expansion
can occur with alpha & beta blockers or direct vasodilators
What is a pheochromocytoma?
a tumor of chromaffin cells of the adrenal medulla –> excess secretion of catecholamines –> increased BP & other symptoms
When are most pheochromocytomas detected?
during surgery or abdominal imaging
or during autopsy
Pheochromocytoma can be associated with this disease
neurofibromatosis
**pts with neurofibromatosis should be screened for pheo
What is the triad of symptoms of a pheochromocytoma?
headache
excessive/generalized sweating
palpitations
**other symptoms: pallor, weight loss, feelings of panic & anxiety
What types of blood pressure patterns can emerge with a pheochromocytoma?
sustained HTN without BP spikes
persistent HTN state w spikes reaching crisis level
normotensive state with brief & sudden spikes in BP
(blank) is seen in more than 50% of pts with pheochromocytoma
orthostatic hypotension
What are the symptoms of a pheochromocytoma-related hypertensive crisis?
dizziness flushing visual disturbances panic/anxiety nausea vomiting epileptic aura
What are some diseases that can present like pheochromocytoma?
paroxysmal vasodilating headaches autonomic dysfunction anxiety or panic disorder acute hypoglycemia CAS cocaine use
What is necessary for the diagnosis of pheochromocytoma?
evidence of excess catecholamine production
What tests do you use to diagnose pheo?
measure urine & plasma catecholamines
urine metanephrines & vanillylmandelic acid
The best approach for pheochromocytoma screening
looking at catecholamines & their metabolites in timed urinary samples
The most sensitive test for pheochromocytoma
plasma free metanephrines
**O-methylated metabolites of catecholamines are continuously seeping from chromaffin tumors
T/F: Measurements of fractionated metanephrines are better than total metanephrines
True
What can you do if catecholamine levels are elevated but not that much?
give a clonidine suppression test –> if pheochromocytoma, clonidine would not suppress catecholamine release
**failure to suppress plasma catecholamines after clonidine therapy –> pheo
What kinds of imaging can be used for pheo?
MRI & CT
I-metaiodobenzylgaunidine (for more specificity)
The only effective therapy approach for pheo?
surgical treatment
This is essential during surgical removal of pheo…
alpha & beta blockers
This should be considered in any patient with spontaneous hypokalemia, moderately severe hypokalemia after using normal doses of diuretics, or refractory HTN
primary hyperaldosteronism
Does primary aldosteronism cause edema?
no, because of aldosterone escape
Patients with primary hyperaldosteronism often develop this comorbid condition
left ventricular hypertrophy –> heart failure
What other diseases present like primary hyperaldosteronism?
SIADH
Liddle’s syndrome
licorice ingestion
(blank) ingestion increases access of cortisol to its receptor and causes Na+ retension & K+ loss
licorice
How to diagnose primary hyperaldosteronism?
low K+ in serum
abnormally high K+ in urine
reduced renin activity
elevated plasma/urine aldosterone
How to treat hyperaldosteronism?
remove an adenoma
medical therapy with spironolactone in pts with bilateral adrenal hyperplasia or high operative risk
Eplerenone is a newer option
What’s Cushing’s syndrome?
excess cortisol production
Two types of Cushing’s syndrome
ACTH-dependent & ACTH independent
What causes 80% of ACTH dependent Cushings syndome?
ACTH secreting adenoma
can also be caused by an ACTH secreting small cell carcinoma of the lung
What causes the ACTH independent forms of Cushings syndrome?
adrenal adenoma or carcinoma
Signs & symptoms of Cushing’s disease
buffalo hump hypertension (increased beta receptors on blood vessels --> increased tone of vasculature) moon face proximal weakness hirtuism emo distubances skin abnormalities insulin resistance osteoporosis loss of libido
Increased (blank) risk in Cushings patients
cardiovascular
How do pts with ectopic ACTH secretion differ from pts with Cushings caused by increased cortisol secretion?
may not have typical symptoms of cortisol excess
instead, skin hyperpigmentation due to MSH overproduction
severe hypertension
hypokalemic alkalosis
Most common cause of Cushing’s syndrome?
exogenous steroid administration
Things that present like Cushings…
fat people with metabolic syndrome & cushingoid appearance
chronic alcohol excess
Best test for diagnosing Cushing’s syndrome?
24 hr free cortisol
**amount of free cortisol in urine can be decreased by renal disease
Test widely used to screen for Cushing’s syndrome
dexamethasone suppression test –> exogenous dexamethasone should reduce plasma cortisol values to less than 2 in normal patients
**measure urinary free cortisol as a confirmation test
How to treat Cushing’s syndrome?
excise the pituitary adenoma
can do adrenalectomy if adrenal adenoma or carcinoma
medical management with ketoconazole if all else fails
Other causes of Cushing’s disease
insulin resistance
sleep apnea
**both contribute to HTN
T/F: Hypertension generally remits with corrective surgery of Cushing’s syndrome unless exposure to excess cortisol has been sufficiently prolonged
True
(blank) should be avoided in pts with Cushing’s syndrome since they increase Ca++ excretion which can exacerbate the negative Ca++ balance state in Cushing’s
loop diuretics
