Poisoning with poison acting on blood

  • Poisoning with carbon monoxide
  • Many toxic substances are able to influence the composition and properties of blood. To such substances concern: arsenic hydrogen cyanide compounds, copper sulfate, lead, aniline, benzene, xylene, some vegetable poisons, etc. however, there is a certain group of toxic substances acting selectively on the blood. From this group of poisons, the highest value for forensic medicine have so-called hemoglobinuria, i.e. poisons that form methemoglobin, and poisons linking blood haemoglobin.
    Poisoning poisons, forming methemoglobin. These poisons are Chornovetsky potassium (vertoletov salt), attestative salt sodium nitrite), aniline, dinitrobenzene and some other substances. Poisoning by these poisons is relatively small.
    Methemoglobinaemia substances widely used in industry (for example, nitrite, potassium and sodium are used in the rubber industry, for preservation of meat and other), in medical practice (as vasodilators and others). Aniline is used as raw material for manufacture of dyes and production of a number of medicines, artificial resins, colored pencils, and for other purposes.
    Under the influence of these poisons the oxidation of ferrous iron contained in the oxyhemoglobin and hemoglobin, the trivalent with the formation of hemoglobin to methemoglobin. Oxygen is connected with iron in the composition of the hydroxyl group (OH). Methemoglobin very persistent connection, so no oxygen is transported to the tissues, causing acidosis. Education in the blood metgemoglobin detected by its color. The blood becomes reddish-brown, the color of purchase and organs. Cadaveric spots - slate-gray, sometimes brownish tint.
    Signs of Toxicity occur when blood levels of 30 % of methemoglobin, and death occurs in the presence in the blood of 70-80 %.
    Depending on the dose received poison and individual peculiarities of the organism poisoned the severity of poisoning may be different. For small cases can be considerable latent period. In severe poisoning, the first symptoms of poisoning may be after 1-2 h after administration of poison. Poisoning is characterized by the blueness of the mucous membranes, the fingers and ears, dizziness, headache, disorientation in space. Then join vomiting, shortness of breath, dizziness. The skin can purchase a grayish color. Severe poisoning may develop rapidly and in a short time lead to death. Acute poisoning is accompanied by hemolysis of blood. In case of poisoning dinitrobenzene exhaled air has a smell of bitter almonds, and when aniline poisoning - the smell of aniline. Perhaps the development of Blackwater principally due to hemolysis and the blockage of the renal tubules.
    Methemoglobinaemia able to temporarily deposited in liver and fat cells. This may explain the repeated methemoglobinaemia with the release of poison in the blood. A large part of nitrites is excreted in the urine.
    Diagnosis of poisoning is based on the anamnesis, the results of chemical analysis of substances causing intoxication, clinical picture, the data of Toxicological studies. Qualitative determination of methemoglobin is carried out by a spectroscope the emergence of the absorption bands in the red part of the spectrum. Spectrophotometric method determines the number of methemoglobin in the blood. In severe poisoning methemoglobin is found in approximately 5-6 days.
    At showdown poisoned, in addition to the typical colour of blood, organs and cadaveric spots are marked venous plethora of all internal organs and serous membranes, minor bleeding in the heart, liver, spleen, kidneys, brain edema, possible necrotic changes in the upper divisions of the respiratory tract and lung inhalation poisoning.
    Poisoning metgemoglobinoobrazovatelami are rare, mainly in the household. Usually they are the result of incorrect use of poisons inside instead of drugs or nutrients.

    Checklist
    1. Describe the mechanism of action hemoglobinuria poisons on the human body.
    2. What is the basis for forensic medical diagnosis death from poisoning with poison and form methemoglobin?
    3. What conclusion is based expert on death from poisoning by carbon monoxide?
    4. What is the meaning of laboratory tests in the diagnosis of death from poisoning hemoglobinuria poisons?
    5. What is the lethal concentration of carboxyhemoglobin in human blood?