Overdose pesticides (organophosphates od)


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Description

Organophosphate pesticides, carbamate pesticides, and organophosphorous compounds (“nerve agents”) developed for chemical warfare (that have been used in terrorist attacks) all inhibit acetylcholinesterase, resulting in cholinergic overstimulation. These chemicals are absorbed by inhalation, by ingestion, and through the skin.

There are several important differences between the nerve agents and the insecticides. The insecticides are oily, less volatile liquids with a slower onset to toxicity but longer-lasting effects. Nerve agents are typically watery and volatile, acting rapidly and severely but for a shorter period of time. Carbamate insecticides have a more limited penetration of the central nervous system, bind acetylcholinesterase reversibly, and result in a shorter, milder course than organophosphates. All can be aerosolized and vaporized.

When there is expression of muscarinic overstimulation symptoms of visual disturbances, tightness in chest, wheezing due to bronchoconstriction, increased bronchial secretions, increased salivation, lacrimation, sweating, peristalsis, and urination can occur.

Causes and Risk factors

The health effects associated with organophosphate poisoning are a result of excess acetylcholine (ACh) present at different nerves and receptors in the body because acetyocholinesterase is blocked. When this occurs symptoms such as muscle weakness, fatigue, muscle cramps, fasciculation, and paralysis can be seen. Symptoms associated with this are tachycardia, hypertension, and hypoglycemia, anxiety, headache, convulsions, ataxia, depression of respiration and circulation, tremor, general weakness, and potentially coma.

Swallowing such poisons can have severe effects on many parts of the body.

Diagnosis and Treatment

It is a good sign that recovery will occur if patients continue to improve over the first 4 - 6 hours after medical treatment.

Although the symptoms are the same for carbamate and organophosphate, recovery is more difficult for organophosphate.

Current antidotes for OP poisoning consist of a pretreatment with carbamates to protect AChE from inhibition by OP compounds and post-exposure treatments with anti-cholinergic drugs. Anti-cholinergic drugs work to counteract the effects of excess acetylcholine and reactivate AChE. ...