Organophosphorus compounds belong to the category of pesticides, which are designed to destroy 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 when they come into contact with the mucous membranes of the nasopharynx and eyes, as well as even with intact skin.
OPS poisoning statistics
Acute intoxication with organophosphorus compounds actually ranks first among other exogenous poisonings, not only in severity, but also in frequency. The lethality of such poisonings is almost 20%, and the frequency is about 15% of all cases.intoxications. 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 severe alcohol intoxication at the time of poisoning with insecticides, the disease proceeds much easier (convulsions and paresis of the respiratory muscles are absent). However, hemodynamic disturbances may be more pronounced.
Possible causes of insecticide poisoning
Poisoning with organophosphorus compounds can be associated with professional activities and occur as a result of non-compliance with the rules for handling toxic substances. The negligence of one or more people can result not only in serious poisoning for themselves, but also lead to mass intoxication.
In addition, organophosphate poisoning can be of a domestic nature. The causes of accidents can be different, for example:
- absence of designations on containers with poisonous liquid stored at home (a person can take poison inside by mistake, or deliberately for the purpose of intoxication);
- storage of insecticides in places accessible to children (children are very curious by nature, and even if the container with the pesticide is signed, a small child can still drink a dangerous liquid and get acute poisoning);
- non-compliance with safety regulations (neglect of protective equipment when using toxic substances in the household, such as a respirator, gloves, goggles, protectiveclothes).
When organophosphorus compounds enter the human body in significant doses, 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 methylmercaptophos, phosphamide, dichlorophosphate;
- moderately toxic - chlorophos, karbofos, methylnitrophos and insecticides based on them, as well as saiphos, cyanophos, tribuphos;
- low toxicity - demuphos, bromophos, temephos.
Symptoms of FOS poisoning
According to the severity of poisoning are divided into 3 stages. The organophosphate poisoning clinic looks like this:
With a mild degree of intoxication (stage I):
- psychomotor agitation and fear;
- shortness of breath;
- dilated pupils (miosis);
- spasmodic abdominal pain;
- increased salivation and vomiting;
- severe headaches;
- high blood pressure;
- profuse sweating;
- hoarse breath.
For moderate form (Stage II):
- psychomotor agitation may persist or gradually change into lethargy, and sometimes into a coma;
- pronounced miosis, pupils stop responding to light;
- symptoms of hyperhidrosis are maximally manifested (salivation (salivation), sweating, bronchorrhea (sputum secretion from the bronchi) is maximized);
- fibrillar twitching of eyelids, chest muscles, shins, and sometimes all muscles;
- periodic appearance of general hypertonicity of the muscles of the body, tonic convulsions;
- the tone of the chest rises sharply;
- blood pressure peaks (250/160);
- Involuntary defecation and urination accompanied by painful tenesmus (false urges).
Severe form of poisoning (Stage III):
- patient falls into a deep coma;
- all reflexes are weakened or completely absent;
- pronounced hypoxia;
- pronounced miosis;
- preservation of symptoms of hyperhidrosis;
- change of muscle hypertonicity, myofibrillation and tonic convulsions by paralytic muscle relaxation;
- respiration is strongly depressed, the depth and frequency of respiratory movements are irregular, paralysis of the respiratory center is possible;
- heart rate drops to critical levels (40-20 per minute);
- tachycardia increases (more than 120 beats per minute);
- blood pressure continues to fall;
- toxic encephalopathy develops with edema and numerous diapedetic hemorrhages predominantlymixed type, caused by paralysis of the respiratory muscles and depression of the respiratory center;
- skin becomes paler, cyanosis appears (skin and mucous membranes become cyanotic).
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 OPC intoxication is relatively easy to make based on the characteristic clinical picture, but whether the outcome is favorable or the victim dies depends largely on the subsequent actions of physicians.
Due to the 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.
Complications commonly associated with severe organophosphorus intoxication include pneumonia, arrhythmia and conduction disturbances, acute intoxication psychoses, etc.
Course of illness
During the first few days after poisoning, the patient is in serious condition due to cardiovascular collapse. Then comes the gradual compensation and his he alth improves. However, after 2-3 weeks, the development of severe toxic polyneuropathy is not excluded. In some cases, a number of cranial nerves may be involved.
The course of such late polyneuropathies is quite protracted, sometimes accompanied by persistent movement disorders. The restoration of the functions of the peripheral nervous system is going poorly. There may also be a recurrence 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 serious organophosphorus poisoning occurs, first aid should include aggressive cleansing of the digestive tract by gastric lavage with a tube, forced diuresis, etc., maintaining breathing, and administering specific antidotes. Further, a set of resuscitation measures is applied, including pharmacotherapy, aimed at maintaining and restoring damaged body functions, including measures to restore cardiac activity, treat homeostasis disorders and exotoxic shock.
Restoration of respiratory function
Organophosphorus compounds ingested in large quantities usually cause respiratory distress caused by excessive oropharyngeal secretion, bronchospasm and paralysis of the respiratory muscles. In this regard, the first thing that doctors try to do is restore airway patency and ensure adequate ventilation. In the presence of abundant vomit and oropharyngeal discharge, aspiration is used (liquid sampling using a vacuum). Atacute OPC poisoning, resuscitation includes tracheal intubation, artificial lung ventilation.
Antidote therapy
The use of antidotes (antidotes) is an essential part of emergency pharmacotherapy for acute poisoning. The drugs 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, prevent dangerous metabolism and eliminate dangerous disorders of the vital functions of the body caused by poisoning.
The antidote for organophosphorus poisoning 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 only an antidote of organophosphorus compounds can save the life of the victim, and the sooner it is administered, the more likely the victim will have a favorable outcome of the disease.
Classification of antidotes
Antidotes are divided into four groups:
- symptomatic (pharmacological);
- biochemical (toxicokinetic);
- chemical (toxicotropic);
- antitoxic immunodrugs.
When the first symptoms of organophosphate poisoning appear, even at the stage of hospitalization of the victim, antidotes of the symptomatic and toxicotropic groups are used, since they have clear indications foruse. Drugs with a toxicokinetic action require strict adherence to the instructions, since emergency doctors cannot always accurately determine the indications for their use. Antitoxic immunodrugs are used in a medical facility.
Specific therapy for acute organophosphate poisoning
A set of measures includes the use of anticholinergics (drugs such as atropine) in combination with cholinesterase reactivators. In the first hour after hospitalization of the patient, intensive atropinization is carried out. Atropine in large doses is administered intravenously until the symptoms of hyperhidrosis are relieved. There should also be signs of a mild overdose of the drug, expressed by dry skin and moderate tachycardia.
To maintain this state, atropine is administered repeatedly, but in smaller doses. Supportive atropinization creates a persistent blockade of the m-cholinergic systems of the damaged organism against the action of the acetylcholine drug for the time required for the destruction and elimination of the toxin.
Modern cholinesterase reactivators are able to effectively activate the inhibited cholinesterase and neutralize various phosphorus-containing compounds. During specific therapy, cholinesterase activity is constantly monitored.
