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Questions and Answers
What is the primary consequence of the inhibition of acetylcholine esterase (AchE) by organophosphates and carbamates?
What is the primary consequence of the inhibition of acetylcholine esterase (AchE) by organophosphates and carbamates?
Which of the following is NOT a classification of pesticides?
Which of the following is NOT a classification of pesticides?
What receptors are primarily affected by the increase of acetylcholine at the neuromuscular junction due to organophosphate exposure?
What receptors are primarily affected by the increase of acetylcholine at the neuromuscular junction due to organophosphate exposure?
Which physiological system is primarily stimulated by high levels of acetylcholine in the parasympathetic response?
Which physiological system is primarily stimulated by high levels of acetylcholine in the parasympathetic response?
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Which of the following is a major risk factor for acute poisoning by organophosphates?
Which of the following is a major risk factor for acute poisoning by organophosphates?
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What effect does high acetylcholine have on the sympathetic ganglia?
What effect does high acetylcholine have on the sympathetic ganglia?
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Which type of receptors are primarily found on smooth muscles and glands?
Which type of receptors are primarily found on smooth muscles and glands?
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What is the estimated number of human poisoning cases attributable to organophosphate and carbamate exposure annually?
What is the estimated number of human poisoning cases attributable to organophosphate and carbamate exposure annually?
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What are signs of local corrosive action in stage 1 of Paraquat poisoning?
What are signs of local corrosive action in stage 1 of Paraquat poisoning?
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Which symptom is not associated with stage 2 of Paraquat poisoning?
Which symptom is not associated with stage 2 of Paraquat poisoning?
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Which treatment option is aimed specifically at increasing elimination in cases of Paraquat poisoning?
Which treatment option is aimed specifically at increasing elimination in cases of Paraquat poisoning?
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What biochemical change is primarily caused by Paraquat poisoning in lung cells?
What biochemical change is primarily caused by Paraquat poisoning in lung cells?
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Which vitamin is used in the prevention of oxidation during Paraquat poisoning treatment?
Which vitamin is used in the prevention of oxidation during Paraquat poisoning treatment?
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What is the immediate action taken to prevent absorption in Paraquat poisoning?
What is the immediate action taken to prevent absorption in Paraquat poisoning?
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In stage 3 of Paraquat poisoning, what is a common respiratory symptom observed?
In stage 3 of Paraquat poisoning, what is a common respiratory symptom observed?
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What role do corticosteroids play in the management of Paraquat poisoning?
What role do corticosteroids play in the management of Paraquat poisoning?
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What is the main method to evaluate cholinesterase activity in cases of suspected poisoning?
What is the main method to evaluate cholinesterase activity in cases of suspected poisoning?
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Which medication is considered the drug of choice for treating severe poisoning due to cholinesterase inhibition?
Which medication is considered the drug of choice for treating severe poisoning due to cholinesterase inhibition?
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What is a potential long-term complication following acute intoxication from nerve agents?
What is a potential long-term complication following acute intoxication from nerve agents?
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What is the fatal dose of paraquat that poses a significant risk of mortality?
What is the fatal dose of paraquat that poses a significant risk of mortality?
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How do oxime compounds function as antidotes for nerve agents?
How do oxime compounds function as antidotes for nerve agents?
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What initial action is recommended for management following exposure to toxic agents?
What initial action is recommended for management following exposure to toxic agents?
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What is the primary mechanism by which organophosphates and carbamates cause toxicity?
What is the primary mechanism by which organophosphates and carbamates cause toxicity?
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Which of the following statements about paraquat is incorrect?
Which of the following statements about paraquat is incorrect?
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What complication may arise 1-4 days after exposure to nerve agents?
What complication may arise 1-4 days after exposure to nerve agents?
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What distinguishes carbamates from organophosphates in terms of their effects on cholinesterase?
What distinguishes carbamates from organophosphates in terms of their effects on cholinesterase?
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Which of the following factors does NOT influence the severity and speed of organophosphate poisoning?
Which of the following factors does NOT influence the severity and speed of organophosphate poisoning?
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What clinical symptom is primarily associated with mild organophosphate poisoning?
What clinical symptom is primarily associated with mild organophosphate poisoning?
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Which symptom is characteristic of severe organophosphate poisoning?
Which symptom is characteristic of severe organophosphate poisoning?
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What is the outcome of the aging process in relation to organophosphate poisoning?
What is the outcome of the aging process in relation to organophosphate poisoning?
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What is NOT a manifestation of systemic organophosphate poisoning?
What is NOT a manifestation of systemic organophosphate poisoning?
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Which statement accurately describes the effects of both organophosphate and carbamate poisoning?
Which statement accurately describes the effects of both organophosphate and carbamate poisoning?
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Study Notes
Organophosphate and Carbamate Insecticides
- Pesticides are chemicals used to kill undesirable pests (plants and animals).
- Pesticides are classified into insecticides, rodenticides, fungicides, and herbicides.
- Organophosphorus compounds are used as liquids or powders.
- These compounds are absorbed through ingestion, inhalation, and skin contact.
- Organophosphates and carbamates are widely used globally.
- These compounds are involved in about 3 million cases of human poisoning and cause approximately 40,000 deaths.
Organophosphate Action
- Organophosphates and carbamates inhibit cholinesterases.
- This leads to an accumulation of acetylcholine at central and peripheral cholinergic nerve endings, including neuromuscular junctions.
- Carbamates cause relatively short-lived inhibition of cholinesterase.
- The carbomate enzyme complex tends to dissociate spontaneously.
Factors Affecting Poisoning Onset and Severity
- The rate of enzyme phosphorylation.
- The rate of spontaneous hydrolysis of the phosphorylated enzyme.
- The rate of aging of the phosphorylated enzyme complex.
Difference Between Organophosphates and Carbamates
- Carbamates are hydrolyzed from the acetylcholinesterase (AchE) site within 24 hours.
- Organophosphates undergo aging when the phosphorylated AchE loses an alkyl side chain, becoming irreversibly inactivated.
Manifestations of Organophosphate/Carbamate Poisoning
- Local: Blistering and redness of the skin. Eye splashes lead to miosis and blurred vision.
- Systemic: Speed of onset depends on route and magnitude of exposure. Symptoms include peripheral muscarinic effects (e.g., gastrointestinal tract, bronchi, heart, bladder, sweat, salivary, and lacrimal glands) – nicotinic actions at neuromuscular junctions, and sympathetic ganglia and CNS effects.
Mild Organophosphate/Carbamate Poisoning Symptoms
- Symptoms include central nervous system stimulant symptoms such as anxiety, restlessness, insomnia, nightmares, tiredness, dizziness, and headache.
Moderate Organophosphate/Carbamate Poisoning Symptoms
- Twitches, muscle fasciculations, tremors, and paralysis, including respiratory muscles.
- Fatigue, generalized weakness causing difficulty walking and impaired speech are also present.
Severe Organophosphate/Carbamate Poisoning Symptoms
- Impaired consciousness. Flaccid paralysis of limb muscles (affecting proximal groups more than distal ones).
- Pulmonary edema. Cyanosis. Convulsions. Atrial fibrillation. Depressed respiration and asphyxia.
Diagnosis of Organophosphate/Carbamate Poisoning
- Diagnosis is difficult if there is no prior exposure history.
- Gastrointestinal symptoms with fever and polymorph leucocytosis may lead to a mistaken diagnosis of gastroenteritis.
- Low cholinesterase activity confirms the diagnosis.
- In severe cases, activity may be less than 10% of normal.
Management of Organophosphate/Carbamate Poisoning
- Removal of clothing, and washing the contaminated skin with soap and water.
- Gastric lavage.
- Blood sample analysis to assess cholinesterase activity and measure respiratory secretions to check for hypoxia
- Replace lost fluids caused by vomiting, diarrhea, and pulmonary edema.
- Atropine is the treatment of choice, given intravenously in 2 mg doses every 10–30 minutes (or as adjusted for children).
- Diazepam (5–10 mg IV) can reduce anxiety and restlessness.
- Oximes like pralidoxime (2-PAM) are used as antidotes to reactivate acetylcholinesterase.
Late Organophosphate/Carbamate Poisoning Complications
- Cranial nerves and brain stem lesions (develop within 1–4 days).
- Peripheral neuropathy (develops 2–3 weeks after exposure, due to axonal degeneration).
- Insomnia, inability to concentrate, and depression.
Paraquat (Bipyridyl Compound)
- Paraquat is a herbicide, a widely used pesticide.
- 93% of paraquat poisoning fatalities are suicides.
- Fatal dose is 4 mg/kg.
- Pure paraquat is highly toxic to mammals, causing acute respiratory distress syndrome (ARDS).
- Fuller's earth or activated charcoal are effective treatments, if given in time.
- Death may occur up to 30 days after ingestion.
Clinical Presentation of Paraquat Poisoning
- Stage 1 (1–5 days): Local corrosive action, hemoptysis (coughing up blood), ulceration of mucous membranes, nausea, diarrhea, and oliguria.
- Stage 2 (2–8 days): Signs of liver, kidney, and cardiac damage; jaundice, fever, tachycardia, myocarditis, respiratory distress, cyanosis, and elevated BUN and serum bilirubin.
- Stage 3 (3–14 days): Pulmonary fibrosis, cough, dyspnea (shortness of breath), tachypnea (rapid breathing), edema, pleural effusion, atelectasis, low arterial oxygen tension, increased alveolar oxygen tension, and respiratory failure.
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Description
Explore the world of organophosphate and carbamate insecticides through this quiz. Learn about their mechanisms of action, common uses, and the factors influencing poisoning effects. This quiz provides essential information on the importance and risks associated with these widely used chemicals.
