The laboratory test of the BMC (for vanillin mindic acid) is prescribed quite often. The substance is usually found in the urine along with other hormones that are produced to combat stress by the adrenaline glands. According to some observations, in patients with a tumor secreting catecholomines, the level of such an acid is higher than normal.
The definition of vanillyl mindic acid is characterized by its structure. It is the end product of the exchange of catecholamines - norepinephrine and adrenaline.
Catecholamines are synthesized in the adrenal medulla, and their entry into the blood is a natural reaction of the body to mental and physical stress (fear, agitation, laughter). Norepinephrine and adrenaline are mediators that transmit impulses between nerve cells. Norepinephrine contributes to the narrowing of blood vessels and, thus, increases the level of blood pressure, adrenaline increases heart rate and increases the metabolic rate.
An increase in vanillin mindic acid in urine or blood is observed in some tumors that intensively produce catecholamines (pheochromocytoma, neuroblastoma).
This acid is present in urine in a small amount, which increases after stress. Pheochromocytoma, neuroblastoma and other neuroendocrine formations are capable of producing a large number of catecholamines, which provokes an increase in metabolic products.
The mechanism of formation of this substance
Vanillyl mindic acid is formed from norepinephrine and epinephrine not directly, but through intermediate metabolites: methanephrine, dihydroxyphenyl glycol and normetanephrine. Dihydroxyphenyl glycol is formed from norepinephrine with the participation of the MAO enzyme, normetanephrine and methanephrine from norepinephrine and adrenaline, respectively, with the participation of the COMT enzyme.
Value in medicine
Of particular importance in clinical medical practice is given exclusively to how much the content of vanillyl mindic acid in the urine is increased, which may indicate the presence of pheochromocytoma. Nevertheless, there is the likelihood of a false-positive diagnosis in stressful conditions. Measurement of methanephrine represents the most objective information about the absence or presence of this pathology.
Pheochromocytoma
Pheochromocytoma is a pathological neoplasm that produces adrenaline and norepinephrine. This tumor occurs at the age of 30-50 years. It has a predominantly benign character and does not give metastases. Symptoms of pheochromocytoma are caused by the periodic release of a large amount of catecholamines into the blood. And as a consequence:
- a sharp increase in pressure and complications caused by this condition (circulatory disorders in the heart and brain, exacerbation of angina pectoris);
- permanent arterial hypertension does not respond well to conventional treatment;
- severe headaches;
- heart palpitations;
- excessive sweating.
Pheochromocytoma is part of the MEN syndrome (multiple endocrine neoplasia, in which tumors occur simultaneously in several endocrine organs).
Surgical treatment allows you to get rid of the tumor and symptoms completely.
Neuroblastoma
Neuroblastoma is a malignant tumor of an early age, most often up to 2 years, 90% - up to 5 years. In rare cases, it can be congenital. It comes from primitive nerve cells of the sympathetic system, located in the abdominal cavity, on the adrenal gland, in the chest cavity, on the neck or in the small pelvis. At the time of diagnosis, 2/3 of the cases already have metastases and germination in nearby organs.
Symptoms of a tumor:
- weakness, fatigue, decreased appetite, fever, impaired behavior;
- anemia;
- joint pain;
- swelling.
Research Features
For laboratory diagnostics that investigate the level of vanillyl mandelic acid, urine or blood is taken for analysis. The study of daily urine gives better results in comparison with a blood test, as this eliminates the daily fluctuations of catecholamines.
Two days before the test, you can not eat vegetables, fruits, products containing vanilla sugar, cheese, chocolate, drink coffee, tea, beer. The following medications are canceled: sulfonylamides (etazol, streptocide, biseptol), diuretics, acellitic acid, methyldopa, iodine preparations. It is forbidden to carry out x-ray studies, use radiopaque drugs and smoke.
A positive laboratory test result and an increase in the concentration of vanillyl mandelic acid must be confirmed by visualization of the tumor or direct determination of urinary catecholamines.
Factors influencing the result
Failure to comply with the requirements for the analysis of urine for vanilla allyl mandelic acid, improper storage of containers and untimely departure to the laboratory may distort the results.
Factors that increase the level of a substance in the blood:
- emotional stress;
- physical exercise;
- medicines and chemicals: Aimalin, Glucagon, Epinephrine, Guanethidine (in initial doses), Levodopa (slightly increased), insulin (after a high dose or insulin shock), lithium preparations, rauwolfia alkaloids, "Nitroglycerin", "Aspirin", "Clofibrate" (the effect depends on the dosage), "Labetolol", "Methyldopa", nalidixic acid, "Guaiacol", "Phenazopyridine", "Oxytetracycline";
- food products: bananas, coffee, chocolate, tea.
Factors that lower acid concentration:
- Chlorpromazine;
- "Debrikovin";
- "Clofibrate" (the effect depends on the dosage);
- Disulfiram
- hydrazine derivatives;
- Guanethidine;
- Imipramine
- "Morphine";
- MAO inhibitors.
Research Objectives
The main goal of vanillin mindic acid analysis is to facilitate the diagnosis of neuroblastomas, pheochromocytomas and ganglioneuromas. The functional state of the adrenal cortex is also assessed.
Deviations from the norm
The level of vanillyl mindic acid in the urine is observed in tumors secreting catecholamines. To diagnose and exclude pheochromocytoma, further studies are recommended, including the study of urinary homovanilic acid excretion. In the case where the diagnosis of pheochromocytoma leaves no doubt, the patient should exclude the MEN, often concomitant with pheochromocytoma (this disease should also be excluded in family members of the patient with confirmed pheochromocytoma).
Reference values
These values are within:
- newborns up to 10 days of life - 1-5.05 mg / day;
- children from 10 days to 1 year - less than 2.0 mg / day;
- children from 1 year to 18 years old - less than 5.0 mg / day;
- adults - 2.1-7.6 mg / day.
We examined how the determination of vanillyl mindic acid in urine and blood is carried out.