Is VMA increased in pheochromocytoma?
Vanillylmandelic acid (VMA) and other catecholamine metabolites (homovanillic acid: HVA and dopamine) are typically elevated in patients with catecholamine-secreting tumors (eg, neuroblastoma, pheochromocytoma, and other neural crest tumors).
What are the 2 diagnostic test for pheochromocytoma?
These tests may include: CT scan, a specialized X-ray technology. MRI , which uses radio waves and a magnetic field to produce detailed images. M-iodobenzylguanidine (MIBG) imaging, a scanning technology that can detect tiny amounts of an injected radioactive compound taken up by pheochromocytomas or paragangliomas.
What is the difference between catecholamines and metanephrines?
Metanephrines are made when your body breaks down hormones called catecholamines. These hormones are made by the adrenal glands. Catecholamines help your body respond to stress. They are sometimes called “fight or flight” hormones.
What labs are abnormal with pheochromocytoma?
The tests of choice to establish the diagnosis of pheochromocytoma are urinary normetanephrine and platelet norepinephrine. A combination of 131I-MIBG scintigraphy and diagnostic tests in urine, blood, or platelets does further improve the sensitivity.
What is VMA pheochromocytoma?
5.4. Vanillylmandelic acid (VMA) is produced in the liver and is a major product of norepinephrine and epinephrine metabolism excreted in the urine. Therefore VMA is a poor diagnostic marker for pheochromocytoma given that very little is derived from catecholamine and metanephrines.
What causes elevated VMA?
Moderately elevated VMA (vanillylmandelic acid) can be caused by a variety of factors such as essential hypertension, intense anxiety, intense physical exercise, and numerous drug interactions (including some over-the-counter medications and herbal products).
Can you have pheochromocytoma with normal metanephrines?
Conclusions: Normal plasma concentrations of metanephrines exclude the diagnosis of pheochromocytoma, whereas normal plasma concentrations of catecholamines and normal urinary excretion of metanephrines do not.
What is the most sensitive test for pheochromocytoma?
Biochemical diagnosis of pheochromocytoma is traditionally performed by examining plasma and total urinary levels of catecholamines and their metabolites over 24 hours. Recent studies have indicated that urine total metanephrines is the most sensitive laboratory test for pheochromocytoma.
Is VMA a metanephrine?
Vanillylmandelic Acid (VMA) Metanephrine and normetanephrine are metabolic products of epinephrine and norepinephrine.
What causes catecholamines to be high?
Abnormally high levels of catecholamines can be a sign of rare adrenal tumors, such as: Neuroblastoma, nerve tissue cancer that typically affects children. Paraganglioma, a tumor that’s often noncancerous and affects nerve cells controlling blood pressure.
What is the best test for pheochromocytoma?
The most commonly ordered blood test for pheochromocytoma is the plasma free metanephrine test. Though more convenient to obtain than a 24-hour urine collection, plasma free metanephrine testing is plagued by frequent false positive results.
What can mimic a pheochromocytoma?
Various tumors including neuroblastomas, ganglioneuroblastomas and ganglioneuromas may mimic pheochromocytomas/paragangliomas. Symptoms associated with pheochromocytoma/paraganglioma, such as high blood pressure, may be induced by the use of certain medications.