Methemoglobinemia

Methemoglobinemia is the presence in the blood metgemoglobin - product of oxidation of hemoglobin some industrial poisons (nitrate, nitrite, arsenic hydrogen, aniline and other) and drugs with a special sensitivity to them (sulfa drugs, quinine, phenacetin , and others). Very rare congenital forms methemoglobinemia associated with anomalies of hemoglobin molecule. When significant methemoglobinemia occurs oxygen starvation, cyanosis, methemoglobinuria.

Methemoglobinemia is the presence in the blood metgemoglobin (MtHb). Methemoglobinemia usually develops under the influence of toxic substances. Many substances entering the body through the digestive system, lungs or skin can cause transformation of hemoglobin into methemoglobin. These include nitrites and nitrates, vertoletov salt, arsenic hydrogen, aniline and its derivatives, phenylhydrazine, pyridine and others, as well as some drugs with long-term use or high individual sensitivity to them (phenacetin, antipyrine, sulfa drugs, quinine and other). Methemoglobinemia weak transferred easily and requires no treatment. When significant M is reduced transport blood oxygen arises oxygen starvation, cyanosis. MtHb does not destroy the red blood cells, but reduces their life, therefore in the blood decreases the content of erythrocytes and hemoglobin, increased the number of reticulocytes and content of bilirubin in the urine grow urobilinemia body. The blood gets brown. The liver and spleen are increasing, impaired kidney function (up to anuria). There methemoglobinuria (see). Congenital methemoglobinemia is a form of hemoglobinase, in which there is a combination of hemoglobin a and M Hemoglobin such people can 10-45% to be in the form of MtHb; these individuals are particularly sensitive to these poisons. Acute Meters find by spectroscopy: MtHb in acidic solutions gives a strip of light absorption at λ=630 MMK. In chronic methemoglobinemia in erythrocytes appear killed Ganza - Ehrlich found in smears of blood at electron microscope color (see the Blood, research methods). The most effective antidotes are reducing agents methylene blue (injected into a vein 0,1-0,15 ml of 1% solution of 1 kg of the patient's weight), ascorbic acid.
Oxygen therapy allows to maintain the supply of tissue dissolved in the plasma oxygen up until manifested the effect of reducing agents.