Organophosphate Poisoning: Its Causes, Symptoms, and Treatment

Introduction

Organophosphate is used worldwide as an insecticide, herbicide, and pesticide to eliminate insects and pests that damage plants. Organophosphate compounds are used for household (cockroach and ant spray) and agricultural purposes. The compound is also used as nerve gas weapons and various medications. These compounds are very harmful and can cause adverse effects on humans. The poisoning from the organophosphate compound occurs due to prolonged high-level exposures. The symptoms produced by organophosphate poisoning are very rapid, but it may take a few weeks to subside. Organophosphate positioning nowadays usually occurs in farmers and workers of agricultural industries due to heavy exposure to these compounds on a regular basis. Therefore, these people should protect themselves from unnecessary exposure with proper control measures.

What Are the Common Organophosphates That Cause Harm to Humans?

The common organophosphate compounds affecting humans are as follows:

• Chlorpyrifos.

• Dursban.

• Malathion.

• Fenthion.

• Parathion.

• Diazinon.

What Are the Symptoms Specific to Organophosphate Poisoning?

1. The symptoms specific to organophosphate poisoning are usually remembered with some common mnemonics, such as DUMBELS for muscarinic effects caused by organophosphate poisoning.

• D - Defecation/diaphoresis.
• U - Urination.
• M - Miosis.
• B - Bronchospasm/bronchorrhea.
• E - Emesis.
• L - Lacrimation.
• S - Salivation.

2. Days of the week for nicotinic signs produced by acetylcholinesterase inhibitor toxicity.

• Monday - Mydriasis.
• Tuesday - Tachycardia.
• Wednesday - Weakness.
• Thursday - Hypertension.
• Friday - Fasciculations.

What Are the Various Symptoms Caused by Organophosphate Poisoning?

The symptoms caused by organophosphate poisoning are as follows:

Mild Symptoms:

• Blurry or impaired vision.

• Watery eyes.

• Nausea.

• Headache.

• Narrowed pupils.

• Running nose.

• Agitation.

• Muscle twitching and weakness.

• Excess saliva.

Moderate Symptoms:

• Dizziness.

• Fatigue.

• Breathing difficulty.

• Disorientation.

• Wheezing.

• Coughing.

• Muscle tremors, twitching, and weakness.

• Involuntary defecation.

• Involuntary urination.

• Drooling.

• Narrowed pupils.

• Sneezing.

Severe Symptoms:

• Confusion.

• Agitation.

• Irregular heartbeat.

• Convulsions.

• Excessive sweating.

• Respiratory arrest.

• Collapse.

• Coma.

What Are the Risk Factors for Organophosphate Poisoning?

The risk of developing organophosphate poisoning is much more in homes and gardens, people working in pest control and agricultural industries, rural and agricultural settings, and veterinary practices. Exposure can also occur due to food as organophosphate is sprayed on the crops.

How Is Organophosphate Poisoning Diagnosed?

The rapid onset of symptoms can detect organophosphate poisoning. The doctor usually diagnoses the poisoning by clinical examination of the symptoms, history of exposure (known or unknown), and blood tests. In addition, renal and liver function tests, glucose levels, and arterial blood gas levels are also evaluated to confirm the diagnosis. Electrocardiogram or ECG is also performed for a clear diagnosis. Diagnosis is also based on response to therapy and RBC (ribonucleic acid) cholinesterase activity.

How Is Organophosphate Poisoning Treated?

Organophosphate poisoning is treated in the following ways:

• Patients exposed to organophosphate poisoning must be isolated to protect themselves from exposure. Also, decontaminating these patients is essential, which can be done by discarding all their clothes.

• Dry agents such as sand, flour, and bentonite are used to decontaminate the patient’s skin. Water can also be used for this purpose.

• Organophosphate ingestion exposure can be reduced with vomiting and diarrhea, but it cannot be induced in a person. Therefore, activated charcoal can be used instead.

• The doctor manages the airway obstruction, and intubation may also be needed in patients present with seizures, bronchospasm, and bronchorrhea. Succinylcholine should be avoided as it can prolong the duration of paralysis in the patient.

• In addition, continuous cardiac monitoring, intravenous access, and pulse oximeter are other vital parts of standard treatment given to organophosphate poisoning patients.

• Atropine is the standard treatment for organophosphate poisoning. It blocks the overstimulation of muscarinic receptors and is given approximately 2 to 5 mg intravenous in adults and 0.05 mg/kg intravenous in children.

• The dose is sometimes doubled every three to four minutes if the patient does not respond to the initial doses. This helps in treating bronchoconstriction and also clears respiratory secretions.

• In case of severe organophosphate poisoning, continuous infusion or bolus of atropine is given to the person for several days until the condition improves.

• Pralidoxime (2-PAM) is sometimes given to the patient within 48 hours of the exposure to produce an effect on nicotine receptors because atropine only works against muscarinic receptors. Pralidoxime can be given along with atropine as it does not cause respiratory depression.

• However, atropine should be administered before pralidoxime or 2-PAM as it can avoid the worsening of muscarinic symptoms. It should be given over 30 minutes (bolus of 30 mg/kg in adults and 20 to 40 mg/kg in children) because rapid administration of atropine can lead to cardiac arrest in the patient. This is followed by continuous infusion of atropine over several days to treat the symptoms of organophosphate poisoning.

• Benzodiazepines such as valium are given to a person having seizures.

What Are the Complications Associated With Organophosphate Poisoning?

The complications associated with organophosphate poisoning are as follows:

• Glycosuria, excess sugar in the urine, and hyperglycemia or high blood sugar levels.

• Inflammation of the pancreas or pancreatitis.

• Problems with fertility.

• Cancer.

• Diabetic ketoacidosis.

• Paralysis.

• Post-traumatic stress disorder and other neurological problems include poor concentration, muscle weakness and twitching, and poor memory.

• Respiratory problems such as accumulation of fluid in the lungs, aspiration pneumonia, bronchospasm, and respiratory failure.

• Irregular heartbeats.

• Seizures, psychosis, neuropathy, and hallucinations.

What Are the Long-term Effects Caused by Organophosphate Poisoning?

The long-term effects caused by organophosphate poisoning include

• Lethargy.

• Irritability.

• Impaired memory.

• Psychosis.

• Confusion.

• Parkinson-like symptoms.

What Are the Differential Diagnosis for Organophosphate Poisoning?

• Botulism.

• Gastroenteritis.

• Nicotine toxicity.

• Myasthenia gravis.

• Mushroom toxicity.

• Guillain Barre syndrome.

• Carbamate poisoning.

Conclusion

Organophosphate poisoning is a serious condition irrespective of exposure dose. The mortality rate due to organophosphate compounds mainly depends on the type and degree of exposure and route, and deaths usually occur due to respiratory arrest. Therefore, a person exposed to organophosphate needs immediate medical attention and several days of hospitalization to monitor symptoms that may be recurrent. A team of doctors usually plans the treatment and diagnoses the case of professionals, including a physician, anesthetist, poison control, and other specialties depending on the organs involved. The treatment is based on trauma protocols and the ICU's (intensive care unit) monitoring of the symptomatic patient.