◆ Poisoning mechanism
The mechanism of organophosphorus pesticide poisoning is generally believed to be the inhibition of cholinesterase activity, which leads to the accumulation of acetylcholine in tissues, which leads to the disorder of cholinergic receptor activity and organ dysfunction with cholinergic receptors. The symptoms caused by the excitement of organ smooth muscle, gland and sweat gland are similar to those caused by toadstool poisoning, which is called toadstool-like symptoms. The symptoms caused by abnormal activities of sympathetic ganglia and rhabdomyosis are similar to nicotine poisoning, so they are called nicotine-like symptoms.
Organophosphorus pesticide poisoning can enter the human body through the skin. Aerosol in spraying process can be inhaled by respiratory tract; Those who take it by mistake are absorbed by the digestive tract. The incubation period is different due to different poisoning methods. After oral administration, people appear nausea and vomiting in the early 5-20 minutes, and then enter a coma; Through the respiratory tract, the incubation period is about 30 minutes, and respiratory irritation symptoms appear after inhalation. Dyspnea, blurred vision, and then systemic symptoms; The longest incubation period is about 2-6 hours, and symptoms such as dizziness, irritability, sweating, decreased muscle tone and ataxia appear after absorption.
◆ Acute poisoning symptoms
1, muscarinic symptoms; Patients with pulmonary edema have nausea, vomiting, abdominal pain and diarrhea, hyperhidrosis, salivation, blurred vision, miosis, dyspnea and increased bronchial secretions.
2, nicotine-like symptoms: such as muscle fiber tremor caused by skeletal muscle excitement. It usually starts with small muscle groups. Such as eyes, face, tongue muscles, etc. , gradually developed into muscle beating, clenched teeth, stiff neck, general convulsions and so on.
3. Central nervous system symptoms
Headache, dizziness, fatigue, lethargy, disturbance of consciousness, convulsions, etc. In severe cases, brain edema or death due to respiratory failure occurred. According to the condition, it can be divided into three levels: mild, moderate and severe.
Mild poisoning: dizziness, headache, fatigue, nausea, vomiting, salivation, hyperhidrosis, blurred vision and miosis.
Moderate poisoning: In addition to the above-mentioned symptoms, there are muscle binding, obvious pupil shrinkage, mild dyspnea, abdominal pain and diarrhea, stumbling gait and mild disturbance of consciousness.
Severe poisoning: in addition to the above symptoms, the pupil is extremely narrow, breathing is extremely difficult, coma, respiratory paralysis.
◆ On-site first aid
1. Take the patient away from the poisoning scene quickly and take off the contaminated clothes, shoes and hats immediately.
2. Wash contaminated hair, skin, hands and feet with plenty of normal saline or clean water or soapy water (trichlorfon poisoning is prohibited).
3. Oral poisoning should induce vomiting and gastric lavage as soon as possible. Gastric lavage with clean water or 1∶5000 potassium permanganate solution (banned for parathion poisoning) or 2% sodium bicarbonate solution (banned for trichlorfon poisoning). Until the eluate is clear and has no pesticide smell. If there is no gastric lavage equipment, poisoned patients can drink plenty of warm water when they are awake. Gently stimulate the throat to cause vomiting, and repeat this for many times until the spit water meets the requirements. This method is simple, rapid and effective.
4. In case of dyspnea, those who have the conditions should take oxygen immediately.
Differential diagnosis and treatment of organophosphorus pesticide poisoning
(1) Prescriptions for specific diseases
1. Qingrejiedu decoction is composed of 9g of viola yedoensis, 9g of Flos Chrysanthemi Indici 12g, 9g of Setaria viridis, 9g of Polygonum aviculare, 9g of Lygodium japonicum and 6g of Glycyrrhiza uralensis. (Chen Youbang, Wang Yongyan. Emergency medicine of traditional Chinese medicine. Fuzhou: Fujian Science and Technology Press, 1995.204)
2. Suoxia Jiedu Decoction is composed of Jinhua 40g (fresh), Bengwan 100g (fresh), Lonicera japonica 100g (dry) and Glycyrrhiza uralensis 100g (dry). Boil the freshly mashed juice with brown sugar water, and then mix the dried grinding powder with the decoction for oral administration. (same as above)
(2) Single Chinese medicine
Datura stramonium 1.5g, decocted in water, with scopolamine as the active ingredient. Fairy 1.5g, decocted in water, with atropine as the active ingredient. Raw green soybean milk (100ml) can be taken orally, which can relieve all kinds of poisons. For acute poisoning, the above three kinds of traditional Chinese medicines are selected.
(3) Specific antidote 1, anticholinergic drug-atropine, etc. 2. Oxime nerve agent-chlorpyrifos, etc.
(4) Treatment: 1, elimination of poison 2, purification of blood through hemoperfusion and hemodialysis 3, specific antidote 4, symptomatic support treatment 5, protection of organ function and timely control of complications.
For those who are seriously poisoned, every minute is very important. They should be sent to a nearby hospital for first aid.
When determining organophosphorus pesticide poisoning, besides clear contact history and typical symptoms, we can also smell a special garlic-like smell from patients' clothes and vomit, which is of great significance to help diagnosis. For patients with severe poisoning, the condition often appears repeatedly, so when the patient is conscious and all symptoms improve, he should still pay close attention to the change of the condition for 3 to 5 days. Once the symptoms recur, it is necessary to deal with them in time.