What are the clinical manifestations of organophosphate pesticide poisoning?
Nov 25, 2025
Source: Cainiu Health
Dr. Wang Lei
Introduction
The clinical manifestations of organophosphate pesticide poisoning include muscarinic symptoms, nicotinic symptoms, central nervous system symptoms, respiratory symptoms, gastrointestinal symptoms, etc. The severity of symptoms is related to the dose and route of exposure. If symptoms such as dizziness, vomiting, and salivation occur, immediate medical attention is recommended. Manifestations include constricted pupils, excessive salivation, and tearing.
Organophosphate pesticide poisoning can present clinically with muscarinic symptoms, nicotinic symptoms, central nervous system symptoms, respiratory symptoms, gastrointestinal symptoms, and others. The severity of symptoms is related to the dose of exposure and the route of contact. If symptoms such as dizziness, vomiting, or excessive salivation occur—suggestive of poisoning—immediate medical attention is recommended.
1. Muscarinic symptoms: These include constricted pupils, excessive salivation and tearing, increased sweating, nausea, vomiting, abdominal pain, diarrhea, frequent urination, and urgency. In severe cases, respiratory distress and pulmonary edema may develop due to cholinergic nerve overactivity.
2. Nicotinic symptoms: Manifestations include muscle tremors, twitching, convulsions, and muscle weakness, starting in the eyelids and face and spreading to the entire body. In severe cases, paralysis of respiratory muscles may lead to asphyxiation, resulting from abnormal excitation at the neuromuscular junctions of striated muscles.
3. Central nervous system symptoms: Early signs include dizziness, headache, restlessness, and confusion. Later stages may involve coma, seizures, hypotension, and even respiratory and circulatory failure, caused by the toxic effects on central nervous system function.
4. Respiratory symptoms: Coughing, chest tightness, and difficulty breathing may occur. Increased secretions can obstruct airways, leading in severe cases to shallow and rapid breathing and cyanosis—common life-threatening manifestations following poisoning.
5. Gastrointestinal symptoms: Symptoms include loss of appetite, nausea, vomiting, abdominal pain, diarrhea, and hyperactive bowel sounds. Some patients may experience hematemesis (vomiting blood) or melena (black tarry stools), associated with irritation of the gastrointestinal mucosa and smooth muscle spasms.
After removal from the contaminated environment, promptly decontaminate any residual toxin on the skin, ensure airway patency, loosen clothing to avoid restriction, place the patient in a quiet and well-ventilated area, and provide warm fluids as appropriate. Do not induce vomiting or administer food orally without medical guidance.
