Dichloroethane poisoning

Among toxic effects caused by substances dangerous to the human body, experts highlight poisoning with dichloroethane, a saturated halogen (chlorinated) derivative of ethylene.

Dichloroethane (ethylene dichloride or 1,2-DCE) is produced in huge quantities and is used in the production of polyvinyl chloride (PVC) and other polymeric materials, fumigants, adhesives and solvents, including for removing paraffins during oil refining, lead from leaded gasoline, and for removing stains in everyday life.

What is the harm of dichloroethane?

For humans, the harm of dichloroethane, like all chlorinated unsaturated hydrocarbons, is not only in its narcotic but also nephrotoxic effect. In case of poisoning with ethylene dichloride, all other systems of the body are also affected - from the lungs and stomach to the brain and central nervous system. The teratogenic and carcinogenic effect of 1,2-DCE on animals has been proven in vivo.

Is it possible to die from dichloroethane? A single ingestion of about 20-30 ml of the liquid substance leads to acute intoxication and is identified as a lethal dose, at which death can occur within 24 hours; 85-125 ml lead to death within five hours, and 150 ml or more – within three hours. The lethal content of 1,2-DCE in the blood is 90 or more mcg/ml (or 500 mg/l).

As clinical statistics from the last three decades show, even after blood purification by hemodialysis, the overall survival rate for acute dichloroethane poisoning did not exceed 55-57%. And without hemodialysis, the mortality rate for severe poisoning reaches 96%.

Causes dichloroethane poisoning

Dichloroethane is a highly flammable and volatile liquid, transparent, with a sweetish taste and the smell of chloroform, poorly soluble in water (8.7 g/l at a temperature of +20°C).

The main causes of poisoning are: inhalation of ethylene dichloride vapors (i.e., entry into the body through the lungs) and swallowing of the liquid substance or liquids containing it. Long-term contact of vapors with unprotected skin or liquid substance contact with large areas of the skin also leads to negative consequences - the development of severe dermatitis, and contact with the eyes - to corneal opacity.

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Risk factors

Risk factors for toxic effects of 1,2-DCE on the body primarily include careless handling of this substance at work and at home. Although cases of deliberate poisoning during suicides are not excluded.

In addition, poisoning of varying severity can occur when people breathe in toxic dichloroethane vapors that leak from hazardous industrial waste dumps and landfills: according to regulations, the level of dichloroethane in the air should not be higher than 3 mg/m3 (in industrial premises – three times higher), and in water bodies – no more than 2 mg/l. At the same time, according to the European Chemicals Agency (ECHA), the average background concentration in Western European cities is 0.4 μg-1.0 μg/m3, and near gas stations, garages and industrial facilities it increases to 6.1 μg/m3.

You can get poisoned by drinking contaminated water: according to FDA standards, the maximum permissible level of 1,2-DCE in drinking water is 1 μg/l, and domestic sanitary standards allow its presence up to 3 μg/dm3.

According to some data, in total, enterprises producing dichloroethane and products using it release up to 70% of the harmful substance into the air, at least 20% into the soil and almost 1.5% into water bodies.

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Pathogenesis

In elucidating the mechanism of action of dichloroethane, which is classified as a protoplasmic toxin (acting at the cellular level), researchers have found that after oral administration into the gastrointestinal tract, systemic absorption lasts no more than an hour with maximum plasma concentrations reaching an average of three to four hours.

Further pathogenesis is caused by the toxic effect not so much of dichloroethane itself, but of its metabolites, which enter the tissues of internal organs with the blood flow – directly into the cells. The liver suffers most of all, since under the influence of its enzymes – in particular, microsomal cytochrome P450 – in the endoplasmic reticulum of the cytoplasm of hepatocytes, oxidation of dichloroethane occurs with the splitting off of chlorine electrons (dechlorination). The result is the formation of toxic 2-chloroacetaldehyde and no less toxic monochloroacetic (chloroethane) acid, which damage the protein structures of cells and completely destabilize tissue trophism at the cellular level.

In addition, dichloroethane binds to cytosolic glutathione-S-transferases (GSTT1 and GSTM1), enzymes that metabolize xenobiotics and carcinogens. It has been experimentally established that, when bound to glutathione, dichloroethane is transformed to form S- (2-chloroethyl) glutathione, which is essentially an alkylating agent that introduces positively charged radicals into cellular proteins and nucleotides. Thus, it becomes a catalyst for reactions that lead to nephrotoxic effects, as well as damage to the vascular endothelium, resulting in a decrease in circulating blood volume and the development of metabolic acidosis.

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Symptoms dichloroethane poisoning

Short-term inhalation exposure – dichloroethane vapor poisoning – at high concentrations initially affects the central nervous system, and the first signs of the toxicogenic stage of poisoning include headache, dizziness, weakness and drowsiness, decreased muscle tone. Euphoria, inadequate reactions, disorientation and hallucinations indicate a disruption of brain and central nervous system functions.

After a short-term improvement in the general condition lasting several hours, the kidneys are exposed to the strong toxic effects of 1,2-DCE metabolites, with the development of acute renal failure and the cessation of urine formation and excretion. Muscle cramps, cyanosis (due to respiratory failure), a sharp decrease and increase in blood pressure, vomiting, gastralgia and diarrhea, as well as weakening of the contractions of the heart muscle (a symptom of myocardial dystrophy) appear. A person may fall into an unconscious state (toxic coma), followed by death.

At low concentrations of vapors, respiratory symptoms appear: irritation and inflammation of the respiratory tract with coughing and wheezing, increased salivation. In people with respiratory diseases, the entry of toxic vapors into the lungs quickly leads to their swelling and respiratory arrest.

Symptoms of acute oral exposure to liquid dichloroethane are similar to those of poisoning with its vapors, but they are more pronounced and manifest themselves as pain along the esophagus and in the epigastric region, nausea and frequent vomiting (with blood), bloody diarrhea. Since dichloroethane is classified as a hepatotoxic (hepatotropic) poison, the main blow falls on the liver - with damage to hepatocytes, an increase in the size of the organ, its inflammation (there may be a feverish state and yellowness of the skin). Clearly localized liver pain is noted on the third or fourth day after the appearance of the first symptoms of poisoning, that is, at the somatogenic stage.

If the worst case scenario of dichloroethane poisoning has been avoided, then in two to three weeks – thanks to treatment – the patient will begin to recover, but complications from individual organs may worsen his health for a long time.

Diagnostics dichloroethane poisoning

Symptoms of poisoning do not always indicate the substance that provoked it. Blood and urine tests can establish the presence of dichloroethane metabolites in the first 24 hours after the toxic substance enters the body.

Blood tests also reveal anemia and neutrophilic leukocytosis in victims.

Instrumental diagnostics consists of taking an ECG.

More information in the material - Diagnostics of acute poisoning

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Differential diagnosis

The task that differential diagnostics must solve is to distinguish ethylene dichloride poisoning from food poisoning, manifestations of acute anthropozoonotic infections, acute gastroenteritis or pancreatitis.

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Treatment dichloroethane poisoning

First aid provided in a timely manner will alleviate the victim's condition and improve the prognosis for the outcome of poisoning, for which it is necessary:

• call a medical resuscitation team or emergency assistance;
• provide access to fresh air; if breathing stops, give artificial respiration;
• If a toxic substance enters the stomach, take activated charcoal and intensively wash the stomach with water (up to 15 liters).

Antidotes for dichloroethane poisoning are limited to a synthetic derivative of L-cysteine (a precursor in the synthesis of the endogenous antioxidant glutathione) – Acetylcysteine (a 5% solution is administered intravenously by drip at a rate of 70-140 mg/kg). This agent accelerates the molecular breakdown of toxic metabolites of 1,2-DCE and activates the synthesis of glutathione in liver cells.

Medicines used in the treatment of the consequences of the toxic effects of dichloroethane have a clear symptomatic focus:

• glucose (infusions of 5% solution) and plasma-substituting drugs (Polyglyukin, Rheopolyglyukin, etc.);
• Unithiol (5% solution – 0.5-1 ml/kg, four times a day, intramuscularly);
• Cimetidine (0.2 g intramuscularly every 4-6 hours);
• lipoic acid (0.5% solution intramuscularly – 3-4 ml);
• injections of corticosteroids (most often prednisolone).

To functionally support metabolic processes in the body against the background of kidney and liver damage, plasmapheresis, hemosorption, and hemodialysis are performed; more details - Hemodialysis for acute poisoning

Vitamins are prescribed: ascorbic acid, thiamine, pyridoxine, cyanocobalamin.

Also read – Symptomatic Intensive Care for Poisoning

Prevention

Preventive measures against poisoning with dichloroethane and other chlorinated hydrocarbons include compliance with all safety regulations at work and at home.

Employees of enterprises dealing with this toxic substance must work in rooms with constant forced ventilation, in industrial filter respirators (gas masks) and in protective clothing.

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Forecast

It is possible to predict the outcome of dichloroethane poisoning, and intensive care and resuscitation specialists do this by objectively assessing the physiological and functional parameters of the patient's body and individual organs. For this, doctors have clear criteria and systems. Read more - Assessing the severity of patients' conditions and predicting the outcome

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