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VMA; the primary end-product of catecholamine metabolism excreted in the urine. Urinary VMA levels are used in screening patients for pheochromocytoma.
va·nil·lyl·man·del·ic ac·id (VMA),(vă-nil'il-man-del'ik as'id),
Misnomer for 4-hydroxy-3-methoxymandelic acid (α,3-dihydroxy-2-methoxybenzeneacetic acid); the major urinary metabolite of adrenal and sympathetic catecholamines (for example, from both epinephrine and norepinephrine); elevated in most patients with pheochromocytoma.
vanillylmandelic acid/va·nil·lyl·man·del·ic ac·id/ (vah-nil″il-man-del´ik) an excretory product of the catecholamines; urinary levels are used in screening patients for pheochromocytoma. Abbreviated VMA.
vanillylmandelic acid (VMA)
a urinary metabolite of epinephrine and norepinephrine. It may be measured in the urine to determine the levels of these catecholamines. A greater than normal amount of VMA is characteristic of a pheochromocytoma or neuroblastoma. Increased concentrations of this acid may raise the blood pressure and indicate the presence of tumors of the adrenal glands or nervous system, muscular dystrophy, and myasthenia gravis; they may be caused by stress, exercise, or certain drugs or foods. Normal amounts in the urine of adults after 24-hour collection are 1.5 to 7.5 mg; in the urine of infants, it is 83 mg/kg of body weight. Also called 3-methoxy-4-hydroxymandelic acid.
va·nil·lyl·man·del·ic ac·id(VMA) (vă-nil'il-man-del'ik as'id)
The major urinary metabolite of adrenal and sympathetic catecholamines; elevated in most patients with pheochromocytoma.
an excretory product of the catecholamines found in the urine; used as a test in the diagnosis of phaeochromocytoma.