Organophosphorus compounds belong to the category of pesticides, which are intended for the destruction of weeds, insects and rodents.
These insecticides are widely used not only in the agricultural industry, but also in everyday life. Many varieties of FOS are highly toxic and can cause serious poisoning both when they enter the body and in contact with the mucous membranes of the nasopharynx and eyes, as well as even with intact skin.
FOS poisoning statistics
Acute intoxication with organophosphorus compounds actually occupies the first place among other exogenous poisonings, not only in severity, but also in frequency. The mortality rate of such poisoning is almost 20%, and the frequency is about 15% of all cases of intoxication. Of interest is the fact that alcohol is a kind of antidote for poisoning with organophosphorus compounds. In victims who were in a state of extreme intoxication at the time of poisoning with insecticides, the disease is much easier (convulsions and paresis of the respiratory muscles are absent). However, hemodynamic disturbances can be more pronounced.
Possible causes of insecticide poisoning
Organophosphate poisoning can be associated with professional activities and may occur due to non-compliance with the rules for the treatment of toxic substances. The negligence of one or several people can result in not only serious poisoning for themselves, but also lead to mass intoxication.
In addition , poisoning with organophosphorus compounds can be domestic in nature. The causes of accidents can be different, for example:
- the lack of designations on containers with toxic liquids stored at home (a person may take poison inside by mistake, or intentionally with the aim of intoxication);
- storage of insecticides in places accessible to children (children are very curious by nature, and even if a container with a pesticide is signed, a small child can still drink a dangerous liquid and get acute poisoning);
- non-observance of safety regulations (neglect of protective equipment when using toxic substances in the household, such as a respirator, gloves, glasses, protective clothing).
When organophosphorus compounds in significant doses enter the human body, they can cause damage to various parts of the central nervous system, which leads to neuritis, paralysis and other serious consequences, up to death.
Classification of organophosphorus compounds by degree of toxicity
- most toxic - insecticides based on thiophos, metaphos, mercaptophos, octamethyl;
- highly toxic - preparations based on methyl mercaptophos, phosphamide, dichlorophosphate;
- medium toxic - chlorophos, karbofos, methylnitrophos and insecticides based on them, as well as saiphos, cyanophos, tribufos;
- low toxicity - demufos, bromofos, temefos.
Symptoms of FOS poisoning
The severity of poisoning is divided into 3 stages. The clinic of organophosphate poisoning is as follows:
With a mild degree of intoxication (stage I):
- psychomotor agitation and a sense of fear;
- labored breathing;
- dilated pupils (miosis);
- spastic pain in the abdomen;
- increased salivation and vomiting;
- severe headaches;
- high blood pressure;
- heavy sweating;
- hoarse breathing.
With moderate form (stage II):
- psychomotor agitation may persist or gradually be replaced by inhibition, and sometimes by a coma;
- severe miosis, pupils stop responding to light;
- symptoms of hyperhidrosis are maximally manifested (salivation (salivation), sweating, bronchorea (sputum production from the bronchi) is maximized);
- fibrillar twitching of the eyelids, chest muscles, legs, and sometimes all muscles;
- the periodic appearance of general hypertonicity of the muscles of the body, tonic convulsions;
- sharply increases the tone of the chest;
- blood pressure reaches maximum values (250/160);
- involuntary bowel movements and urination, accompanied by painful tenesmus (false urge).
Severe poisoning (stage III):
- the patient falls into a deep coma;
- all reflexes are weakened or completely absent;
- severe hypoxia;
- pronounced myosis;
- preservation of symptoms of hyperhidrosis;
- a change in muscle hypertonicity, myofibrillation, and tonic seizures with paralytic relaxation of muscles;
- breathing is strongly depressed, the depth and frequency of respiratory movements are irregular, paralysis of the respiratory center is possible;
- heart rate decreases to critical rates (40-20 per min.);
- tachycardia worsens (more than 120 beats per min.);
- blood pressure continues to fall;
- toxic encephalopathy develops with edema and numerous diapedetic hemorrhages of a predominantly mixed type, caused by paralysis of the respiratory muscles and depression of the respiratory center;
- the skin turns sharply pale, cyanosis appears (the skin and mucous membranes acquire a bluish color).
The consequences of poisoning with phosphorus-containing insecticides
When organophosphorus compounds enter the body, first aid provided in a timely and correct manner is one of the fundamental factors determining the further course of the disease. The diagnosis of FOS intoxication is relatively easy to make according to the characteristic clinical picture, however, whether the outcome will be favorable or the victim will die, largely depends on the subsequent actions of physicians.
Due to its high toxicity, organophosphorus compounds, when ingested, cause irreparable harm to almost all vital organs and systems. In this regard, even with a favorable outcome, it is not possible to fully restore the functions of some organs.
Among the complications that are usually accompanied by severe intoxication with organophosphorus substances include pneumonia, disturbances in the rhythm and conduction of the heart, intoxication psychoses in acute form, etc.
Course of the disease
During the first few days after poisoning, the patient is in serious condition due to cardiovascular collapse. Then comes a gradual compensation and his well-being improves. However, after 2-3 weeks the development of severe toxic polyneuropathy is not ruled out. In some cases, a number of cranial nerves may be involved.
The course of such late polyneuropathies is quite protracted, sometimes accompanied by persistent motor disorders. Recovery of the functions of the peripheral nervous system is going badly. There may also be a return of acute disorders such as cholinergic crises. This is explained by the fact that the deposited organophosphorus compound is "ejected" from various tissues into the circulatory system.
Treatment
When a serious poisoning occurs with organophosphorus compounds, first aid should include aggressive cleansing of the digestive tract by washing the stomach with a probe, forced diuresis, etc., maintaining breathing and the use of specific antidotes. Next, a set of resuscitation measures is applied, including pharmacotherapy, aimed at maintaining and restoring damaged body functions, including measures to restore cardiac activity, treatment of homeostasis disorders and exotoxic shock.
Respiratory Recovery
Organophosphorus compounds that enter the body in large quantities usually cause respiratory distress, the causes of which are excessive oropharyngeal secretion, bronchospasm and paralysis of the respiratory muscles. In this regard, the first thing that doctors are trying to do is to restore airway patency and provide adequate ventilation. In the presence of abundant vomit and oropharyngeal discharge, aspiration is used (intake of liquids by vacuum). In acute poisoning with FOS, resuscitation measures include tracheal intubation, mechanical ventilation.
Antidote therapy
The use of antidotes (antidotes) is an essential part of emergency pharmacotherapy for acute poisoning. Preparations of this group affect the kinetics of a toxic substance in the body, ensure its absorption or elimination, reduce the effect of toxins on receptors, inhibit dangerous metabolism and eliminate dangerous disorders of the vital functions of the body caused by poisoning.
The antidote for poisoning with organophosphorus compounds is taken along with other specialized drugs. Pharmacotherapy is carried out in parallel with general resuscitation and detoxification therapeutic measures.
It must be remembered that if there is no possibility of urgent resuscitation, then the life of the victim can be saved only by the antidote of organophosphorus compounds, and the sooner it is administered, the greater the chance the victim will have a favorable outcome of the disease.
Antidote Classification
Antidotes are divided into four groups:
- symptomatic (pharmacological);
- biochemical (toxicokinetic);
- chemical (toxicotropic);
- antitoxic immunopreparations.
When the first symptoms of poisoning with organophosphorus compounds appear, even at the stage of pre-hospitalization of the victim, antidotes for the symptomatic and toxicotropic groups are used, since they have clear indications for use. Toxicokinetic drugs require strict adherence to the instructions, as emergency doctors can not always accurately determine the indications for their use. Antitoxic immunopreparations are used in a medical facility.
Specific therapy for acute poisoning with organophosphorus compounds
The range of measures includes the use of anticholinergics (medications such as atropine) in combination with cholinesterase reactants. In the first hour after hospitalization of the patient, intensive atropination is carried out. Atropine in large doses is administered intravenously to stop the existing symptoms of hyperhidrosis. There should also appear signs of a weak overdose of the drug, expressed by dry skin and moderate tachycardia.
To maintain this state, atropine is reintroduced, but in smaller doses. Supportive atropination creates a persistent blockade of the m-cholinergic systems of the damaged body against the action of the drug acetylcholine for the time necessary to destroy and eliminate the toxin.
Modern reactivators of cholinesterase are able to effectively activate inhibited cholinesterase and neutralize various phosphorus-containing compounds. When carrying out specific therapy, constant monitoring of cholinesterase activity is carried out.