Incidentaloma laboratory findings: Difference between revisions
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==Overview== | ==Overview== | ||
Laboratory findings consistent with the diagnosis of incidentaloma include an abnormal 1 mg overnight dexamethasone for subclinical Cushing's syndrome that should be confirmed with 24-hour urinary free cortisol, serum ACTH concentration, and dehydroepiandrosterone sulfate (DHEAS). In patients with adrenal masses that have a probability for pheochromocytoma, routine measurement of 24-hour urinary fractionated metanephrines and catecholamines should be done. All patients with hypertension and an adrenal incidentaloma should be evaluated by measurements of plasma aldosterone concentration and plasma renin activity. | Laboratory findings consistent with the diagnosis of incidentaloma include an abnormal 1 mg overnight [[dexamethasone]] for subclinical [[Cushing's syndrome]] that should be confirmed with 24-hour urinary free [[cortisol]], serum [[Adrenocorticotropic hormone|ACTH]] concentration, and [[dehydroepiandrosterone sulfate]] ([[DHEAS]]). In patients with [[Adrenal gland|adrenal]] masses that have a probability for [[pheochromocytoma]], routine measurement of 24-hour urinary fractionated [[Metanephrine|metanephrines]] and [[catecholamines]] should be done. All patients with [[hypertension]] and an [[Adrenal gland|adrenal]] incidentaloma should be evaluated by measurements of plasma [[aldosterone]] concentration and plasma [[renin]] activity. | ||
==Laboratory Findings== | ==Laboratory Findings== | ||
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* An undetectable level of serum [[Adrenocorticotropic hormone|ACTH]] is also supportive of the diagnosis of subclinical [[Cushing's syndrome|Cushing’s syndrome]]. | * An undetectable level of serum [[Adrenocorticotropic hormone|ACTH]] is also supportive of the diagnosis of subclinical [[Cushing's syndrome|Cushing’s syndrome]]. | ||
* Hormonal evaluation in the patients with subclinical [[Cushing's syndrome]] showed the following: [11] | * Hormonal evaluation in the patients with subclinical [[Cushing's syndrome]] showed the following: [11] | ||
* Low baseline secretion of ACTH | * Low baseline secretion of [[Adrenocorticotropic hormone|ACTH]] | ||
* Lack of suppressibility of cortisol secretion after 1 | * Lack of suppressibility of [[cortisol]] secretion after 1 mg [[dexamethasone]] | ||
* Supranormal 24-hour urinary cortisol excretion | * Supranormal 24-hour urinary [[cortisol]] excretion | ||
* Disturbed cortisol circadian rhythm | * Disturbed [[cortisol]] [[circadian rhythm]] | ||
* Blunted plasma ACTH responses to corticotropin-releasing hormone (CRH) | * Blunted plasma [[Adrenocorticotropic hormone|ACTH]] responses to [[corticotropin-releasing hormone]] [[Corticotropin-releasing hormone|(CRH]]) | ||
=== Pheochromocytoma === | === [[Pheochromocytoma]] === | ||
* In patients with adrenal masses that have a probability for pheochromocytoma, routine measurement of 24-hour urinary fractionated metanephrines and catecholamines should be done. | * In patients with [[Adrenal gland|adrenal]] [[Mass|masses]] that have a probability for [[pheochromocytoma]], routine measurement of 24-hour urinary fractionated [[Metanephrine|metanephrines]] and [[catecholamines]] should be done. | ||
=== '''Aldosteronomas''' === | === '''[[Hyperaldosteronism|Aldosteronomas]]''' === | ||
* All patients with hypertension and an adrenal incidentaloma should be evaluated by measurements of plasma aldosterone concentration and plasma renin activity. | * All patients with [[hypertension]] and an [[Adrenal gland|adrenal]] incidentaloma should be evaluated by measurements of plasma [[aldosterone]] concentration and plasma [[renin]] activity. | ||
* | * Measurement of plasma [[aldosterone]] to [[renin]] ratio (ARR) is the best initial test for the evaluation of primary [[Hyperaldosteronism|aldosteronism]] (44, 106, 111). A range of ARR cutoff values from 20 to 100 | ||
* A serum aldosterone level below 0.25 nmol/liter (9 ng/dl) makes a diagnosis of primary aldosteronism highly unlikely (113, 114). | * A serum [[aldosterone]] level below 0.25 nmol/liter (9 ng/dl) makes a diagnosis of primary [[aldosteronism]] highly unlikely (113, 114). | ||
* Borderline values should be repeated: | * Borderline values should be repeated: | ||
# After correcting hypokalemia | # After correcting [[hypokalemia]] | ||
# While the patient is on salt restriction | # While the patient is on salt restriction | ||
# In the morning in a sitting position | # In the morning in a sitting position | ||
# After resting for at least 15 min before proceeding with confirmatory tests (44, 91) | # After resting for at least 15 min before proceeding with confirmatory tests (44, 91) | ||
* Patients with an elevated ARR should proceed with a confirmatory test such as the salt loading test or saline suppression test (44, 115). | * Patients with an elevated ARR should proceed with a confirmatory test such as the [[salt]] loading test or [[saline]] suppression test (44, 115). | ||
==References== | ==References== | ||
Revision as of 15:30, 31 August 2017
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief:
Overview
Laboratory findings consistent with the diagnosis of incidentaloma include an abnormal 1 mg overnight dexamethasone for subclinical Cushing's syndrome that should be confirmed with 24-hour urinary free cortisol, serum ACTH concentration, and dehydroepiandrosterone sulfate (DHEAS). In patients with adrenal masses that have a probability for pheochromocytoma, routine measurement of 24-hour urinary fractionated metanephrines and catecholamines should be done. All patients with hypertension and an adrenal incidentaloma should be evaluated by measurements of plasma aldosterone concentration and plasma renin activity.
Laboratory Findings
Subclinical Cushing's syndrome
- Subclinical Cushing's syndrome should be ruled out by performing the 1 mg overnight dexamethasone suppression test (DST).
- An abnormal 1 mg overnight dexamethasone should be confirmed with 24-hour urinary free cortisol, serum ACTH concentration, and dehydroepiandrosterone sulfate (DHEAS).
- An undetectable level of serum ACTH is also supportive of the diagnosis of subclinical Cushing’s syndrome.
- Hormonal evaluation in the patients with subclinical Cushing's syndrome showed the following: [11]
- Low baseline secretion of ACTH
- Lack of suppressibility of cortisol secretion after 1 mg dexamethasone
- Supranormal 24-hour urinary cortisol excretion
- Disturbed cortisol circadian rhythm
- Blunted plasma ACTH responses to corticotropin-releasing hormone (CRH)
Pheochromocytoma
- In patients with adrenal masses that have a probability for pheochromocytoma, routine measurement of 24-hour urinary fractionated metanephrines and catecholamines should be done.
Aldosteronomas
- All patients with hypertension and an adrenal incidentaloma should be evaluated by measurements of plasma aldosterone concentration and plasma renin activity.
- Measurement of plasma aldosterone to renin ratio (ARR) is the best initial test for the evaluation of primary aldosteronism (44, 106, 111). A range of ARR cutoff values from 20 to 100
- A serum aldosterone level below 0.25 nmol/liter (9 ng/dl) makes a diagnosis of primary aldosteronism highly unlikely (113, 114).
- Borderline values should be repeated:
- After correcting hypokalemia
- While the patient is on salt restriction
- In the morning in a sitting position
- After resting for at least 15 min before proceeding with confirmatory tests (44, 91)
- Patients with an elevated ARR should proceed with a confirmatory test such as the salt loading test or saline suppression test (44, 115).