Methemoglobinemia, what is Methemoglobinemia

Treatment of methemoglobinemia is not always required. For example, if an increase in the level of methemoglobin is caused by taking certain groups of drugs, they are simply canceled. Subsequently, all blood counts are normalized.

The main goal of a standard course of therapy is to convert oxidized iron to normal. For this, patients are prescribed the introduction of a solution of methylene blue (“Chromosmon”). As a rule, this measure is enough so that all unpleasant symptoms disappear after a few hours. Also, in the framework of drug therapy, blood transfusions and ascorbic acid are prescribed. In infants with enzymatic pathologies, riboflavin is supplemented with therapy.

Many pregnant women who have been diagnosed with methemoglobinemia (you already know what it is) do not realize that the disease is very serious. Symptoms of pathology are usually only exacerbated by toxicosis. Such ladies first of all need quality medical care. A prolonged course of the disease can provoke fetal hypoxia and various developmental abnormalities. Therapy in this case is selected individually.

In acute toxic methemoglobinemia, the causes are eliminated first. Then oxygen therapy is prescribed, during which the patient breathes concentrated oxygen. A similar approach to treatment ensures the normalization of metabolic processes and the subsequent destruction of pathological hemoglobin.

One of the components of red blood cells is hemoglobin. It is a complex protein, iron is present in the composition. He is responsible for transporting oxygen throughout the body.

При развитии патологического процесса, как метгемоглобинемия, отмечается увеличение уровня гемоглобина в крови, который насыщен уже окисленным железом.

Главная отличительная особенность метгемоглобина в том, что он не способен соединяться с молекулами кислорода и переносить его к человеческим органам и тканям, вследствие чего наступает кислородное голодание организма.

В крови здорового человека метгемоглобин присутствует в незначительных количествах. Норма метгемоглобина в крови составляет примерно 1% (с погрешностью до 3%). Если его присутствие превышает указанную норму, наступает заболевание – метгемоглобинемия.

Биохимический анализ требует специальной предварительной подготовки пациента. Приём пищи производится не менеечасов до проведения анализа крови. Это основывается на том, что любой пищевой продукт способен оказывать влияние на показатели крови, изменяя тем самым результат анализа, что в свою очередь, может повлечь за собой неправильный диагноз и лечение. Так же, стоит ограничить приём жидкости. Противопоказан приём алкоголя, сладкого кофе и чая, молока, фруктовых соков.

Во время забора крови пациент находится в положении сидя или лёжа. Кровь для биохимического анализа забирают из локтевой вены. Для этого немного выше локтевого сгиба накладывается специальный жгут, затем вводится игла непосредственно в вену и, производится забор крови (примерно, 5 мл). После чего кровь помещают в стерильную пробирку, на которой обязательно указывают данные пациента, и только после этого её направляют в биохимическую лабораторию.

Общий белок – отображает содержание белка в сыворотке крови. Уровень общего белка может увеличиваться при различных заболеваниях печени. Снижение количества белка наблюдается при недостаточном питании, истощении организма.

  • у новорожденных он составляетг/л
  • у детей до года –г/л
  • от 1 до 4 лет –г/л
  • от 5 до 7 лет –г/л
  • от 8 до 15 лет –г/л
  • у взрослых –г/л

Альбумин – простой белок, растворимый в воде, составляющий около 60% всех белков сыворотки крови. Уровень альбуминов снижается при патологиях печени, ожогах, травмах, заболеваниях почек (нефритический синдром), недостаточном питании, на последних месяцах беременности, при злокачественных опухолях. Количество альбуминов увеличивается при обезвоживании организма, а также после приёма витамина А (ретинола). Нормальное содержание сывороточного альбумина составляетг/л у детей в возрасте до 3 лет, у взрослых –г/л. Альбумины составляют от 56,5 до 66,8 %.

Альфа-1-глобулины. Норма 3,5 — 6,0 %, что составляет 2,1 — 3,5 г/л.

Общий билирубин – жёлто-красный пигмент, который формируется в результате распада гемоглобина. В норме содержится 8,5 — 20,5 мкмоль/л. Содержание общего билирубина встречается при любом виде желтухи.

Glucose – is the primary source of energy in the body. The norm is 3,38 – 5,55 mmol / L. High blood glucose (hyperglycemia) indicates the presence of diabetes mellitus or impaired glucose tolerance, chronic diseases of the liver, pancreas and nervous system.

Total cholesterol is an important organic compound that is a component of lipid metabolism. Normal cholesterol is 3,9 – 5,2 mmol / L. An increase in its level may accompany the following diseases: obesity, diabetes mellitus, atherosclerosis, chronic pancreatitis, myocardial infarction, coronary heart disease, some liver and kidney diseases, hypothyroidism, alcoholism, gout.

  • up to 10 years 0,34 – 1,24 mmol / l
  • 10 – 15 years 0,36 – 1,48 mmol / l
  • 15 – 20 years 0,45 – 1,53 mmol / l
  • 20 – 25 years 0,41 – 2,27 mmol / l
  • 25 – 30 years 0,42 – 2,81 mmol / l
  • 30 – 35 years 0,44 – 3,01 mmol / l
  • 35 – 40 years 0,45 – 3,62 mmol / l
  • 40 – 45 years 0,51 – 3,61 mmol / l
  • 45 – 50 years 0,52 – 3,70 mmol / l
  • 50 – 55 years 0,59 – 3,61 mmol / l
  • 55 – 60 years 0,62 – 3,23 mmol / l
  • 60 – 65 years 0,63 – 3,29 mmol / l
  • 65 – 70 years 0,62 – 2,94 mmol / l

An increase in blood triglycerides is possible with acute and chronic pancreatitis, atherosclerosis, coronary heart disease, hypertension, diabetes mellitus, alcoholism, hepatitis, cirrhosis of the liver, obesity, cerebral vascular thrombosis, gout, chronic renal failure, etc.

ALAT – alanine aminotransferase. An enzyme necessary to determine the functional state of the liver. Normal content in krovinkat / l. An increased ALAT content is characteristic of myocardial infarction, damage to the heart and somatic muscles.

Classification

Depending on the origin, methemoglobinemia can be congenital or acquired.

  • fermentopathy (there is a sharp reduction in methemoglobin reductase, resulting in cyanosis of the skin and visible mucous membranes, the so-called “latent anemia” appears on the background of latent tissue hypoxia);
  • M-hemoglobinopathy (there is a synthesis of abnormal globins, manifested in children under six months of age).

There are six main stages of the disease, depending on the level of methemoglobin concentration in the blood:

  • stage I – the level of methemoglobin is at a level of less than 3% (symptoms are practically absent, the skin becomes grayish);
  • stage II – the level of the substance is in the range from 15 to 30%, cyanosis develops, the blood acquires a dark brown color;
  • stage III – methemoglobin level – from 30 to 50%, the patient suffers from headaches, heart rhythm is disturbed, fainting conditions occur, shortness of breath with the slightest physical exertion;
  • stage IV – methemoglobin concentration ranges from 50 to 70%, arrhythmia, convulsions appear, the condition is accompanied by central nervous system problems, up to loss of consciousness, falling into a coma;
  • stage V – the level of the substance in the blood exceeds 70%. There is a lack of air, with hypoxia, death occurs.

Causes and factors leading to the development of the disease

Every day a person uses various medications, comes into contact with chemicals, buys products in stores. Few people understand that poisoning directly with nitrates can provoke a disease such as methemoglobinemia. What it is?

Hemoglobin is a complex protein that is part of red blood cells. It contains iron and is responsible for transporting oxygen to all elements of the body. Methemoglobinemia is a pathology accompanied by an increase in hemoglobin saturated with oxidized iron. Its development is accompanied by weakness and headaches, shortness of breath with increased loads.

Methemoglobin is a form of hemoglobin that has lost the ability to bind and transport oxygen. Normally, it should be formed in the process of metabolism, and in the body is present in small amounts. With an increase in its concentration, tissues begin to experience oxygen deficiency, responding to changes in a specific clinical picture.

Methemoglobinemia may be:

  1. Primary, or congenital. In this case, methemoglobin accounts for 20 to 50% of the total complex protein.
  2. Secondary. Methemoglobin concentration ranges from excessively low to dangerously high.

Depending on the causes of development, methemoglobinemia can be of exogenous or endogenous origin. In the first case, the disease occurs under the influence of external factors, and in the second, it is diagnosed in patients with impaired synthesis and absorption of nitrates.

The congenital form of the disease is hereditary and most often develops for the following reasons:

  1. Fermentopathy – a decrease in the activity of methemoglobin reductase. This is a special enzyme characterized by the ability to reduce oxidized iron.
  2. M hemoglobinopathy. Pathology is manifested by the synthesis of hemoglobin, in the composition of which oxidized iron is initially present.

Elevated levels of methemoglobin are diagnosed in all newborn babies. This phenomenon is considered a variant of the norm. It is due to the low activity of enzymes and the stress that the child experiences during childbirth. Over time, the situation usually normalizes.

The reasons for the development of human methemoglobinemia secondary are many. As elements that contribute to the oxidation of iron, the following can be distinguished:

  • nitrates;
  • chlorobenzene;
  • aniline dyes;
  • potassium permanganate;
  • food and water contaminated with nitrates.

In addition, some drugs contribute to the development of the disease. For example, Paracetamol, Dapsone, Vikasol, Nitroglycerin, Lidocaine, etc. However, you should not be afraid to take these medications, since a negative reaction is possible only with a significant overdose.

Congenital methemoglobinemia is a hereditary pathology and occurs due to:

  • fermentopathy – reducing the activity of a particular enzyme, methemoglobin reductase, capable of reducing oxidized iron;
  • M-hemoglobinopathy, manifested by the synthesis of hemoglobin, which initially includes oxidized iron.

Most often, congenital methemoglobinemia occurs in the indigenous inhabitants of Alaska, Yakutia, Greenland.

Elevated methemoglobin levels are found in all newborn babies. This is the norm. This feature is associated with low enzyme activity and stress experienced during childbirth. Over time, the situation normalizes and the concentration of pathological hemoglobin decreases to normal values. But if the baby develops enterocolitis, provoked by bacteria with increased nitro-forming function and diarrhea, he may have acquired methemoglobinemia.

There are many reasons for the development of secondary pathology. As substances that provoke the oxidation of iron, can be:

  • Paracetamol;
  • Vikasol;
  • Nitroglycerine;
  • Amyl nitrite;
  • Dapson;
  • Nitroprusside;
  • Phenazopyridine;
  • Phenacetin;
  • Lidocaine;
  • Novocaine;
  • potassium permanganate (potassium permanganate);
  • sulfonamide drugs;
  • antimalarial drugs (quinine);
  • aniline dyes;
  • silver nitrate;
  • chlorobenzene;
  • trinitrotoluene;
  • nitrates;
  • food and water heavily contaminated with nitrates.

Do not be afraid to take the above medicines, since they can cause methemoglobinemia only with a significant overdose.

Specialists distinguish only two forms of methemoglobinemia, namely:

  1. Congenital or primary, when methemoglobin accounts for up to 50% of the total number of hemoglobin in the blood.
  2. Acquired or secondary – its levels can be very different.

The acquired form may be of exogenous or endogenous origin. If the disease is caused by the influence of certain external factors, its specific varieties are diagnosed, including water-nitrate methemoglobinemia against the background of excessive consumption of food and water with a high proportion of nitrates in its composition.

If the disease is caused by the influence of internal factors, then it is a consequence of the problem with the production and absorption of nitrates, which is typical for enterocolitis and other similar pathologies.

Regardless of the form of the disease, the stages of the development of the pathological process are distinguished:

  • The proportion of methemoglobin is 3%, the first manifestations appear – gray skin.
  • In the second stage, its presence increases to 30%, while the blood acquires a dark color, cyanosis appears.
  • The third stage assumes its presence in an amount of up to 50%. Symptoms of methemoglobinemia in this case will be headache, shortness of breath and regular fainting.
  • The fourth stage of the development of the disease involves a real danger, since its presence increases to 70%. This suggests the development of a coma in humans, supplemented by serious disorders in the central nervous system.
  • The fifth stage is the hardest. The presence of methemoglobin can reach 100%, which is fraught with sudden death due to oxygen deficiency.

Antibiotics, in particular Ceftriaxone, rarely cause methemoglobinemia

In infants, signs of hereditary methemoglobinemia are noticeable immediately after birth. In these children, blueness of the mucous membranes, skin of the lips, earlobes and nails is observed. As a rule, the disease is accompanied by a number of other disorders, among which the following are distinguished:

  • underdevelopment of limbs;
  • change in the normal shape of the skull;
  • thalassemia – a disorder of hemoglobin synthesis;
  • vaginal atresia (in girls);
  • lag in psychomotor development.

Consult a doctor if you suspect a congenital methemoglobinemia. What is it and how to properly treat the disease, the doctor should tell at the reception.

Methemoglobinemia: what is it, tests, symptoms, causes, treatment

The manifestations of this disease can be very diverse. They vary depending on the presence of chronic ailments, the general condition of the human body, as well as the stage of development of this disease. Often the symptoms are implicit or completely absent. In such cases, it can be detected only by performing a general blood test.

Typical manifestations of the disease are:

  • general malaise;
  • frequent headaches and dizziness;
  • rapid breathing;
  • sleep disturbances, frequent diarrhea;
  • nervousness;
  • problems with orienteering;
  • gray skin tone;
  • impaired breathing, including shortness of breath;
  • possible fainting;
  • cramps in the lower extremities;
  • problems with the functioning of the musculoskeletal system;
  • sudden mood swings, memory problems.

Among the signs of the disease, experts call diarrhea, which is one of the signals about an increase in the proportion of methemoglobin.

If the disease is inborn, it can be seen by the color of the skin, coupled with a lag in mental and physical development. In the future, the appearance of drowsiness and unreasonable crying is possible.

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An abnormal form of hemoglobin in which ferrous atoms are oxidized to ferric under the influence of toxic substances, oxygen-containing drugs, or due to hereditary disorders of hemoglobin molecules is called methemoglobin.

The transformation of natural hemoglobin into metahemoglobin occurs by its oxidation, as a result of which the iron formula Fe2 passes into the trivalent state – Fe3.

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Features

A distinctive feature of methemoglobin is that it is not able to connect with oxygen molecules and transfer it to human organs and tissues, as a result of which the body begins to starve to oxygen.

Methemoglobinemia is a disease in which a significant part of the hemoglobin in the red blood cells contains oxidized ferric iron. Hemoglobin, as an essential element, is responsible for the transport of oxygen throughout the body. Oxidizing to methemoglobin, it loses this property, which leads to hypoxia of organs and tissues.

There are three forms of methemoglobinemia:

  • Congenital An extremely rare form of the disease. Does not affect the duration and quality of life.
  • Genetic. With this form of the disease, a genetic predisposition becomes the cause of the increase in the proportion of methemoglobin. In this case, a congenital metabolic error occurs, which leads the body to a state of methemoglobinemia. The consequences of this form of the disease are very serious: mental retardation, microcephaly. Life expectancy is short, as a rule, people die at a young age.
  • Acquired. This form is more common. It occurs due to exposure to the body of substances that cause methemoglobinemia. It occurs as a result of taking a number of drugs or under the influence of toxic substances.

Symptomatic signs and consequences of methemoglobinemia depend on the form and level of methemoglobin:

  • Level 3-15% – a characteristic pale, gray or cyanotic skin tone appears, thickening of the nail plates.
  • The level of 15-20% – cyanosis appears.
  • Level 25-50% – physiological consequences are noted: migraine, general weakness, shortness of breath, chest pain, confusion.
  • The level of 50-70% – fainting, mental disorders, convulsions, coma.
  • A level of more than 70% is fatal.

Both adults and children, including newborns, are susceptible to methemoglobinemia.

A characteristic feature for all forms of methemoglobinemia is a chocolate-brown hue of blood, when sampling tests it does not change its color.

To diagnose the disease in an adult patient, the doctor evaluates the symptoms, prescribes laboratory tests. When making a diagnosis, it is very important to identify the cause of hypoxia.

If this condition is caused by poisoning, it is necessary to exclude the possibility of carbon monoxide entering the bloodstream. When this substance enters the blood, a strong compound is formed – carboxyhemoglobin.

Excessive amounts of methemoglobin in the blood can be observed in both women and men. However, men are susceptible to this disease by 66.59% less than women. Cases of fatal outcome in men with methemoglobinemia were not recorded.

To diagnose methemoglobinemia in newborns, the doctor performs special tests and studies to measure the level of methemoglobin in the blood.

In particular, such studies include:

  • Blood color. With the disease, it acquires a rich brown color.
  • Blood biochemistry. Increased bilirubin during biochemical analysis may indicate methemoglobinemia.
  • Analysis of the concentration of methemoglobin in the blood of the child.
  • General blood analysis. If the child is sick, the ESR level decreases, and hemoglobin and red blood cells increase.

In children with a hereditary disease, the following external signs of the disease are often observed:

  • Pronounced cyanosis on the skin and mucous membranes.
  • Skull deformity.
  • Lag in psychomotor development.

Methemoglobinemia affects both male and female children. However, newborn girls run the risk of acquiring the disease in a hereditary or congenital way much more often than boys.

The reason for the concentration of methemoglobin in the blood is the ingestion of pathogenic chemicals as a result of an overdose of drugs based on aniline and its derivatives. A substance that can convert hemoglobin to methemoglobin is called a methemoglobin former.

  • local anesthetics;
  • nitrates and nitrites;
  • nitrogen oxide;
  • primaquin;
  • naphthalene;
  • hydrazine derivatives;
  • sulfonamides.

It is worthwhile to be especially careful with medicines made on the basis of methemoglobin formers. Before using the drug, you must familiarize yourself with the instructions for use and dosage.

Cyanosis is one of the signs of pathology

To maintain health, it is worth knowing how to prevent the formation of excess methemoglobin in the blood. There are two ways to do this.

  1. To prevent the pathogenic effects of iron oxidizing agents that penetrate into the red blood cells before they damage the hemoglobin molecules. For this, the enzyme glutathione peroxidase is introduced into the blood. In this case, reduced glutathione acts on pathogenic oxidizing agents in the blood, neutralizes them and prevents the synthesis of methemoglobin. This method will help prevent the further development of methemoglobinemia, however, it can lead to the formation in the blood of substances obtained as a result of hemoglobin denaturation – Heintz bodies.
  2. Restore hemoglobin molecules damaged by oxidized iron. This method is used using two enzymatic systems: NAND-dependent and NANDP-dependent methemoglobin reductase. In the first system, the substances that repair the damaged hemoglobin are the products of the anaerobic stage of glucose processing (NAND), in the second – hexose monophosphate conversion (NANDF). As a result of hexose monophosphate conversion under the influence of hexose-6-phosphate dehydrogenase (G-6f-DG), a reducing agent is synthesized – nicatinamide – adenine dinucleotide phosphate (NANDPH). He takes part in the transformation of methemoglobin to hemoglobin in the presence of NADPH-methemoglobin reductase, as well as the reduction of oxidized ferric iron with the participation of NANDP-dependent glutathione reductase.

Methemoglobin is a hazardous substance. The synthesis of hemoglobin in methemoglobin leads to serious violations of the composition and quality of the blood. In order to avoid its concentration in the body, it is necessary to systematically carry out preventive procedures and monitor the dosage of the drugs used.

Each of us periodically uses various medicines, contacts with harmful substances, buys products on the market. But few people know that nitrate poisoning can cause a disease such as methemoglobinemia. What is this pathology and how to recognize it?

Hemoglobin is a complex protein that is part of red blood cells. It contains iron and provides oxygen delivery to all cells of the body. Methemoglobinemia is a disease in which the level of hemoglobin saturated with oxidized iron in the blood rises.

Methemoglobin is a form of hemoglobin that is not able to bind and carry oxygen. Normally, it is formed in the process of metabolism and is present in the body in small quantities, without affecting the transport function of red blood cells.

But with an increase in its concentration for one reason or another, the body is deficient in oxygen and reacts with a number of disorders.

Normally, the amount of methemoglobin does not exceed 1,5%.

The skin of patients with methemoglobinemia acquires a grayish-blue tint

  1. Primary (congenital). Methemoglobin accounts for 20–50% of the total hemoglobin volume.
  2. Secondary (acquired). The concentration of methemoglobin in the blood varies from extremely low to life-threatening. Depending on the causes, they distinguish:
    1. Methemoglobinemia of exogenous origin (i.e., provoked by external factors). For example, water-nitrate methemoglobinemia is the result of drinking water with a very high concentration of nitrates.
    2. Methemoglobinemia of endogenous origin (toxic). The disease occurs in patients with chronic enterocolitis with impaired synthesis and absorption of nitrates or other similar pathologies.

Elevated levels of methemoglobin are found in all newborn babies. This is the norm. This feature is associated with low enzyme activity and stress experienced during childbirth.

  • cyanosis of the skin (the skin acquires an abnormal shade – from gray to earth tones);
  • sudden respiratory failure;
  • weakness of the body;
  • severe headaches and frequent dizziness;
  • sudden loss of consciousness;
  • the occurrence of seizures;
  • heart rhythm disturbance;
  • disorientation in space;
  • violation of the musculoskeletal system;
  • fatigue;
  • sleep disturbance;
  • mood swings;
  • increased tearfulness.

Diagnostics and differential diagnostics

To diagnose the disease in an adult patient, the doctor evaluates the symptoms, prescribes laboratory tests. When making a diagnosis, it is very important to identify the cause of hypoxia. If this condition is caused by poisoning, it is necessary to exclude the possibility of carbon monoxide entering the bloodstream. When this substance enters the blood, a strong compound is formed – carboxyhemoglobin.

  • examination by a therapist;
  • blood spectroscopy;
  • general and clinical blood tests;
  • a sample with the internal introduction of methylene blue;
  • hemoglobin electrophoresis;
  • Genetics consultation (if necessary).

Blood spectroscopy is performed as follows: a drop of blood of a healthy person and a drop of blood of a patient who is diagnosed with a disease are applied to the sheet. As a rule, in a healthy person, venous blood acquires a red color, and with methemoglobinemia it remains dark brown.

A blood test is aimed at eliminating the occurrence of heart defects, diseases of the adrenal glands, lungs, which are also accompanied by blueness of the skin and a change in color, texture of the mucous membranes.

An important diagnostic sign of methemoglobinemia is the dark cinnamon color of the blood, which, when placed in a test tube or on filter paper, does not change its color to red. With a positive test, spectroscopy is carried out, the concentration of MtHb, the activity of NAD-dependent methemoglobin reductase, and hemoglobin electrophoresis are determined.

In a general blood test, compensatory erythrocytosis, an increase in Hb, reticulocytosis, and a decrease in ESR may be present. In the study of biochemical blood parameters, a slight bilirubinemia is determined due to an increase in the indirect fraction of the pigment. For chronic methemoglobinemia, the appearance of Heinz-Erlich bodies in red blood cells is typical.

In patients with enzymatic or toxic methemoglobinemia, a therapeutic test with the intravenous administration of methylene blue is indicative – after the injection, cyanosis quickly disappears, and the skin and visible mucous membranes turn pink.

When analyzing the causes of methemoglobinemia, it is important to find out if the patient has had contact with toxic substances, or has taken methemoglobin-forming drugs. If there is a suspicion of congenital methemoglobinemia, the pedigree is studied, a geneticist is consulted, the type of inheritance of the blood pathology is determined.

  • Level 3-15% – a characteristic pale, gray or cyanotic skin tone appears, thickening of the nail plates.
  • Level% – cyanosis appears.
  • Level 25-50% – physiological consequences are noted: migraine, general weakness, shortness of breath, chest pain, confusion.
  • The level of 50-70% – fainting, mental disorders, convulsions, coma.
  • A level of more than 70% is fatal.

To diagnose the disease in an adult patient, the doctor evaluates the symptoms, prescribes laboratory tests. When making a diagnosis, it is very important to identify the cause of hypoxia. If this condition is caused by poisoning, it is necessary to exclude the possibility of carbon monoxide entering the bloodstream. When this substance enters the blood, a strong compound is formed – carboxyhemoglobin.

Excessive amounts of methemoglobin in the blood can be observed in both women and men. However, men are susceptible to this disease by 66.59% less than women. Cases of fatal outcome in men with methemoglobinemia were not recorded.

Determining the presence of methemoglobinemia is not difficult. An important diagnostic sign is a dark brown shade of blood, which does not change its color in the air. If this test is positive, the following studies are carried out to confirm the diagnosis:

  • spectroscopy to determine the concentration of methemoglobin;
  • assessment of methemoglobin reductase activity;
  • hemoglobin electrophoresis (the amount of normal and pathological hemoglobin is determined);
  • general blood test – shows an increase in the level of red blood cells, hemoglobin, reticulocytes, a decrease in ESR (erythrocyte sedimentation rate);
  • biochemical blood test – reveals an increase in the amount of bilirubin and the appearance of Heinz-Erlich bodies in red blood cells.

In the toxic form of the disease, the test with methylene blue is the most indicative, after the introduction of which cyanosis quickly passes.

Differential diagnosis is carried out with diseases such as:

  • congenital heart defects, for which a typical change in the fingers is the type of “drum sticks”;
  • abnormalities of the development of the lungs, having similar manifestations with cardiac pathologies.

Determining the presence of a pathological process in the body is quite simple. Methemoglobinemia is indicated by a brownish tint of blood, which does not change color when interacting with oxygen. If this test shows a positive result, a comprehensive examination is prescribed to confirm the preliminary diagnosis. It consists of the following activities:

  • spectroscopy;
  • general blood analysis;
  • hemoglobin electrophoresis;
  • blood chemistry.

In the case of a toxic form of pathology, the test with methylene blue is considered the most indicative. After the introduction of this substance, cyanosis usually disappears.

The external sign of the disease is an unnatural dark brown color of the blood, which does not change to normal. Specific laboratory studies include determining the concentration of MtHb along with the activity of NAD-dependent methemoglobin reductase and spectroscopy.

According to the results of a general blood test, there is a decrease in the number of ESR in combination with compensatory erythrocytosis. After conducting a biochemical study, bilirubinemia becomes apparent. Heinz-Erlich bodies in red blood cells may also appear.

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Another specific study for such a disease is a therapeutic test, which involves the intravenous administration of methylene blue. After the injection, cyanosis quickly disappears, and the skin turns pink.

Treatment

If severe symptoms of the disease appear, consult a doctor. Pulling with treatment can be life threatening.

What will the doctor do

If the disease does not manifest itself clinically, then its treatment is not required.

If symptoms appear, then the level of methemoglobin in the blood has increased. Therapy is aimed at its transformation into hemoglobin and alleviation of the patient’s condition. To convert methemoglobin to hemoglobin, a number of intravenous drugs are used.

Additionally, oxygenation (oxygenation), the administration of a drug that improves respiratory function are prescribed. In especially severe cases, an exchange blood transfusion is prescribed.

In the absence of vivid symptoms, treatment may not be required, but it is very important to conduct a dynamic examination of the patient. If the disease was caused by a drug, the medication is canceled, the symptoms disappear.

For the effective treatment of methemoglobinemia, it is prescribed:

  • drug therapy aimed at converting methemoglobin to hemoglobin (intake of ascorbic acid, first in large doses, and then in a maintenance volume, the introduction of methylene blue at the rate of 1 mg per 1 kg of patient weight is recommended);
  • oxygen therapy (with severe cyanosis of the skin, when it acquires an earthy tint with cyanosis);
  • the introduction of ascorbic acid (approximate volume – 2 g);
  • intramuscular administration of vitamin B12;
  • glucose intake at a rate of 50 ml per day;
  • blood transfusion.

In case of toxic damage, complex treatment of the skin, mucous membranes is prescribed, passive oxygen therapy is recommended.

Patients with a lack of clinical manifestations do not need special therapy. With a significant concentration of MtHb in the blood and the developed symptoms of methemoglobinemia, drug therapy is prescribed that promotes the conversion of methemoglobin to hemoglobin. Ascorbic acid and methylene blue possess such reducing properties.

The course of hereditary and medicinal methemoglobinemia is usually benign. An adverse outcome is possible with severe forms of toxic methemoglobinemia with a high content of MtHb in red blood cells. Patients with a similar pathology should avoid contact with methemoglobin-forming substances, hypothermia and other provoking factors.

The treatment of the disease is carried out under the supervision of a hematologist. Corrections require only a state with spectrophotometry values ​​above 15 nm.

Patients with M-hemoglobinopathies (hereditary forms of the disease, which are characterized by a structural change in the hemoglobin molecule) do not need treatment.

The treatment of methemoglobinemia is based on the conversion of oxidized iron to normal. For this purpose, patients are prescribed the introduction of methylene blue (Chromosmon). In most cases, this is enough for all the symptoms of the pathology to disappear without a trace within a few hours. The dosage of methylene blue should be treated with special scrupulousness, since excessive amounts of it can lead to hemolytic anemia.

Symptoms of pathology in pregnant women may increase under the influence of toxicosis. Such women are primarily in need of medical attention, since prolonged hypoxia provokes severe violations of the fetus, and in the early stages spontaneous abortions.

Also in the framework of drug therapy are shown:

  • blood transfusion and ascorbic acid intake in case of enzyme deficiency;
  • the appointment of ascorbic acid and riboflavin in infants with fermentopathies.

No special diet is prescribed to patients. But nevertheless, it is recommended to exclude from the diet purchased vegetables, fruits, processed meat products (sausages, sausages, etc.) and other products that may contain nitrates.

Treatment with folk remedies is not carried out.

With methemoglobinemia, the outcome is favorable. Complications are usually observed only with the toxic form of the disease. They are caused by prolonged hypoxia (lack of oxygen), as a result of which all organs suffer. In especially severe cases, a fatal outcome is possible.

Treatment of patients with toxic M. and homozygous gene carriers with hereditary enzyme M. with significant (more than 20%) blood methemoglobin and severe symptoms is carried out with specific drugs that contribute to its recovery – ascorbic acid and methylene blue.

Ingestion of ascorbic acid (0,15-0,3 g 3 times a day) already during the first days reduces the concentration of methemoglobin in the blood to 10% of the total amount of Hb. Then they switch to maintenance doses (0,05-0,1 g 3 times a day) for a long time (2-3 months); it is necessary to take breaks lasting 2-4 weeks.

Methylene blue with intravenous administration has a quick effect and after 1 hour the relative concentration of methemoglobin in the blood decreases to 1% or lower. It is used in the form of the Chromosmon preparation, it is administered intravenously slowly at the rate of 1 mg per 1 kg of body weight or in capsules (100 mg each) 3-4 times a day. Patients with M-hemoglobinopathies do not need treatment and are resistant to any therapy.

Forecast and Prevention

Methemoglobinemia disease has a favorable prognosis. Complications are possible only with a toxic form of pathology and untimely seeking medical help. In rare cases, a fatal outcome is likely.

Methemoglobinemia is a serious enough disease, which is unacceptable to ignore the symptoms. Is it possible to avoid its development?

Doctors agree that it is quite easy to prevent an ailment. To do this, you must follow a number of rules:

  • Do not self-medicate, and take the prescribed drugs strictly according to the scheme;
  • avoid direct contact with toxic substances;
  • try not to eat foods grown with nitrates and contaminated water;
  • consult a geneticist before conceiving a child.

The rules of prevention in the case of a congenital form of pathology are somewhat different. Doctors recommend avoiding hypothermia, limiting physical activity and periodically engage in strengthening immunity.

The prognosis depends on the type of M. and the severity of the wedge, manifestations.

Prevention Medical-genetic consultations are necessary to exclude the possibility of marriage of heterozygous carriers M. Contact with chem. agents – methemoglobin formers both in production and in everyday life.

So that children and adults do not have problems with such an ailment as methemoglobinemia, one should strictly adhere to simple preventive recommendations:

  • strict adherence to the dosage of drugs;
  • preventing chemical compounds from entering the body, and for this, personal protective equipment should be used;
  • refuse to eat foods high in nitrates, since such a disease is the main symptom of poisoning with such a substance;
  • drinking only purified water;
  • Before you have a baby, you need to consult a geneticist;
  • avoidance of hypothermia;
  • continuous strengthening of the immune system;
  • regular passage of a full examination in a medical institution.

Methemoglobinemia in the vast majority of cases has a favorable prognosis, especially with the development of a hereditary and medical form. A fatal outcome develops only in those cases when oxidized hemoglobin reaches critical values.

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Features

For the prevention of methemoglobinemia, it is recommended to follow the recommendations of doctors:

  • Strictly avoid contact with methemoglobin-forming substances;
  • avoid overcooling the body;
  • take vitamins regularly;
  • practice hardening;
  • strengthen the immune system;
  • adhere to the principles of healthy and regular nutrition;
  • for future parents it is important to conduct a medical genetic examination in order to identify a heterozygous carrier.

With timely diagnosis and optimal treatment of methemoglobinemia, the prognosis is favorable. It is especially important to monitor the patient’s condition over time, since with a sharp increase in the content of methemoglobin in red blood cells, the risk of sudden death is high. If the concentration level of methemoglobin in the blood exceeds 70%, hypoxia and death occurs.

Patients diagnosed with methemoglobinemia need a gentle regimen at work and in everyday life. It is necessary to limit physical activity, avoid contact with substances of an oxidizing nature. It is also recommended to regularly ventilate the premises to avoid hypoxia against the background of a lack of oxygen.

Diagnosis and treatment of the disease should be carried out by an experienced specialist, under whose control complex therapy should be carried out with subsequent monitoring.

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Radiation sickness is a complex disease that occurs against the background of the effects of radioactive radiation on the human body. With such a disease, it is affected.

To avoid the development of the disease, you should:

  • clearly observe the dosage regimen of drugs;
  • avoid contact with harmful substances;
  • do not eat contaminated water and products grown with the use of nitrates;
  • consult with a geneticist during pregnancy planning to assess the likelihood of having a sick child.

With congenital pathology, you also need to:

  • avoid hypothermia;
  • limit physical activity;
  • strengthen the immune system.

Signs of water-nitrate methemoglobinemia

This form of the disease has specific characteristics. After poisoning with toxins, it begins to progress rapidly. After drinking even a small amount of contaminated water, the following symptoms may occur:

  • blue skin;
  • violation of orientation in space;
  • headache.

If you do not seek medical help in a timely manner, the condition may worsen. In this case, shortness of breath and arrhythmia, convulsions appear in patients.

In adults, water-nitrate methemoglobinemia usually proceeds in a mild form. In children, it is accompanied by a digestive disorder. Small patients, especially those who are breast-fed, are more susceptible to the disease. When they prepare a mixture using contaminated water, the likelihood of developing serious pathological processes increases several times.

Parents to note

In premature infants, as well as in full-term newborns, a high level of methemoglobin is observed. But even with jaundice and severe hypoxia, this level is not so significant as to ask what it is – methemoglobinemia, and make an appropriate diagnosis.

However, it is necessary to pay attention to the condition of the child in the first year of his life, because with viral enterocolitis, diarrhea, if the newborn has a tendency to metabolic acidosis, secondary endogenous methemoglobinemia can develop very quickly.

It is worth talking about the mixed form when a person was a hereditary gene carrier of the disease, but it began to develop under the influence of external factors.

clinical picture

The intensity of the manifestations of the pathology primarily depends on the concentration of methemoglobin in the blood. Today, its level is determined by spectrophotometry with a special co-oximeter device. Also, the manifestations of the disease are affected by:

  • age of the patient;
  • the presence of concomitant diseases, for example, pathologies of the heart and blood vessels;
  • the presence of provoking factors for the development of methemoglobinemia.

When the concentration of pathological hemoglobin is less than 20% of the total amount of hemoglobin, a person does not observe any changes in the functioning of the body.

The severity of symptoms depends on the amount of methemoglobin in the blood, the rate of M.’s development and the compensatory abilities of the cardiovascular, respiratory systems and hematopoiesis in the process of adaptation to hypoxia. When the content of methemoglobin in the blood is less than 20% of the total amount of Hb, M.’s symptoms are usually absent.

Hereditary Enzymopenic M. in homositic gene carriers is detected during the neonatal period and is characterized by cyanosis of the skin and visible mucous membranes, especially noticeable in the nasolabial triangle, earlobes, nail bed, and oral cavity. The color of the skin and visible mucous membranes varies from gray-earth to dark purple. Cyanosis (see

According to M.S. Kushakovsky (1968) and other researchers, patients have hemodynamic changes (tachycardia, increased cardiac output) that are compensatory in nature.

Often M. is combined with other congenital anomalies (atresia of the vagina and uterus, underdevelopment of the hands, changes in the shape of the skull, deformation and impaired function of the gut-intestinal tract, thalassemia, deficiency of the glucose-6-phosphate dehydrogenase enzyme, etc.).

Venous blood is unusually dark in color with a brownish tint, does not grow red with shaking. There are no changes in the hemogram (see) and the morphology of red blood cells, however, in patients with a relatively high methemoglobin content (more than 20%), secondary compensatory erythrocytosis is observed (up to 6,0-7.0 million cells in 1 μl) with an increase in the total content of H b to 17,0-24,0 g%, an increase in blood viscosity and a slowdown in ROE.

The amount of active Hb is reduced, and even in the presence of erythrocytosis, oxygen deficiency is detected in patients. The dissociation curve of oxyhemoglobin (see. Blood) is sometimes shifted to the left. Some patients have mild reticulocytosis and an increase (up to 1,5-2.0 mg%) of indirect serum bilirubin, which suggests the presence of slight hemolysis; at intensive hemolysis methemoglobin can be present in urine (see. Methemoglobinuria).

Patients with alpha-chain variants of M-hemoglobinopathy of cyanosis from the moment of birth, and with p-chain variants, cyanosis develops from 6 months of age. In addition to severe cyanosis, other symptoms are not observed.

Inherited Enzymopenic M. in heterozygous gene carriers (before sulfanilamide preparations enter the body) is asymptomatic; the concentration of methemoglobin in the blood is normal or slightly increased (1-2%), the activity of methemoglobin reductase is reduced by 50%.

Toxic M. of exogenous and endogenous origin proceeds sharply or chronically and in symptoms resembles a hereditary enzyme M; quite often combined with hemolysis (see).

Svetlana Borszavich

General practitioner, cardiologist, with active work in therapy, gastroenterology, cardiology, rheumatology, immunology with allergology.
Fluent in general clinical methods for the diagnosis and treatment of heart disease, as well as electrocardiography, echocardiography, monitoring of cholera on an ECG and daily monitoring of blood pressure.
The treatment complex developed by the author significantly helps with cerebrovascular injuries and metabolic disorders in the brain and vascular diseases: hypertension and complications caused by diabetes.
The author is a member of the European Society of Therapists, a regular participant in scientific conferences and congresses in the field of cardiology and general medicine. She has repeatedly participated in a research program at a private university in Japan in the field of reconstructive medicine.

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