Pesticide intoxication

From WikiLectures

Template:Infobox - disease

  • Pesticides are substances against harmful organisms
  • mainly against insects (insecticides), rodents (rodenticides), molluscs (molluscicides), weeds (herbicides), fungi (fungicides) ...
  • systemic pesticides - penetrate plants, protect more effectively (organophosphates)
  • contact pesticides - kill organisms only in affected areas
  • the most toxic are some insecticides, molluscicides and herbicides
  • The most common intoxication is rodenticides - it is not so severe

Organophosphate insecticides[edit | edit source]

Character noxy[edit | edit source]

Organophosphates are esters of phosphoric acid , either containing sulfur (suffix -thion) and cyp450 metabolizes them to an active derivative containing oxygen (-oxone), or have equal oxygen in the molecule;

  • high acute toxicity ,
  • the spectrum of preparations does not contain highly toxic organophosphates,
  • they do not accumulate in the environment, they are low in adipose tissue, they are not significantly carcinogenic ,
  • representatives - fenitrothion (Sumithion), diazinon , etc.

Professional exposure[edit | edit source]

The risk of intoxication arises during production, less so during further processing;

  • in addition, they contain solvents and other additives.

Etiopathogenesis[edit | edit source]

Irreversible acetylcholinesterase (ACHE) inhibition - ACH → ACH degrading enzyme accumulates;

  • the accumulation of ACH can explain most of the symptoms of intoxication, a disorder of cholinergic transmission,
  • the synthesis of the new ACHE takes 60 days ,
  • as a late consequence, neuropathy is due to degeneration of PNS axons.

Toxicity[edit | edit source]

depends on the ability to inhibit ACHE, on the concentration ...

Clinical picture[edit | edit source]

First symptoms:

  • with a decrease in ACHE activity below 70% (reduction below 20% - severe poisoning),
  • life-threatening poisoning - activity is immeasurable,
  • depends on the speed of boarding ...
  • acute - accumulating ACH affects two types of receptors (muscarinic - vegetative motor, nicotine - neuromuscular discs), then it is also a mediator in the CNS ,
  • muscarinic symptoms - tearing, salivation, sweating, miosis, vomiting, abdominal pain, diarrhea, bronchial hypersecretion, bronchospasm, bradycardia (as if parasympathetic),
  • the preganglial innervation of the sympathetic nervous system is also affected by ACH → in mild poisoning, the symptoms are expressed differently ( the sympathetic nervous system may antagonize this),
  • nicotine symptoms - fasciculations, tremor, convulsions, paralysis of the respiratory muscles,
  • CNS symptoms - disorientation, headaches , convulsions, respiratory depression, coma .
  • The cause of death is respiratory failure (all systems are comprehensively involved) and cardiac arrhythmias
  • chronic - accumulation may occur rarely, symptoms such as acute,
  • late neuropathy - not due to ACH , about 7-21 days after severe poisoning - calf cramps, numbness, paraesthesia in the legs, weakness.

Investigation methods[edit | edit source]

  • For monitoring professional exposure - erythrocyte ACHE,
  • we examine neuropathy with EMG .

Differential diagnosis[edit | edit source]

Heavier exposures may resemble a stroke , a milder infectious disease.

Therapy[edit | edit source]

Pharmacological antidote is atropine - blocks muscarinic symptoms (not nicotine), before administration of atropine it is necessary to correct respiratory and cardiovascular disorders (give oxygen ) - doses are controlled by mucosal humidity, in severe poisoning - biochemical antidote - oxime - ACHE reactivator (eg obidoxime) ), comprehensive care for vital functions, in case of convulsions - diazepam (in low doses).

Carbamate insecticides[edit | edit source]

Characteristics of noxy[edit | edit source]

Carbamic acid derivatives, directly inhibiting ACHE (without activation), representatives - pirimicarb (Pirimor®), etc., also include neostigmine (Syntostigmine®) and physostigmine (natural alkaloids, indirectly acting, parasympathomimetic , used in glaucoma ... ).

Professional exposure[edit | edit source]

In agriculture, due to the lower toxicity they are in preparations for gardeners !; in industry they are used for the production of plastics.

Etiopathogenesis[edit | edit source]

They enter through all gateways, they inhibit ACHE but reversibly !!!, spontaneous reactivation occurs quite quickly, they do not settle.

Clinical picture[edit | edit source]

Acute symptoms - as with organophosphates, but they occur earlier, have a milder and shorter course, chronic poisoning - are not known (max. Dermatitis).

Investigation methods[edit | edit source]

ACHE determination is important only after intoxication (inhalation goes too fast).

Differential diagnosis[edit | edit source]

It can resemble an infectious disease, it is important to distinguish between organophosphate poisoning, neuropathy does not occur.

Therapy[edit | edit source]

Atropine is enough, then symptomatically and supportively.

Rodenticides[edit | edit source]

  • The most commonly used anticoagulants - warfarin (Kumatox), brodifacoum (Volid, Talon) ...,
  • they are small in granules, have a delayed effect, usually potentiated by repeated consumption of poison by rats,
  • delayed toxicity does not deter rats from eating, moreover, it does not vomit rats,
  • low toxicity to humans is also an important condition (they just lie on the ground, they can be ingested by children ...),
  • occupational exposure - does not pose a risk.

Etiopathogenesis[edit | edit source]

It is well absorbed from the GIT (worse through the skin), they are vit.K antagonists → they block the synthesis of coagulation factors II (prothrombin), VII, IX and X lethal doses contain up to kilograms of the product.

Clinical picture[edit | edit source]

  • Acute - most often in young children, ingestion of a few grains does not manifest itself, with a larger amount Quick is prolonged, bleeding symptoms are usually only in suicidal attempts (suicide is usually unsuccessful),
  • chronic - very rare.

Investigation methods[edit | edit source]

Monitoring of INR value.

Therapy[edit | edit source]

Specific antidote - vitamin K ( Kanavit ) - indicated after ingestion of a large dose.

Links[edit | edit source]

related articles[edit | edit source]

Source[edit | edit source]

  • BENEŠ, Jiří. Study materials  [online]. © 2007. [feeling. 2010]. < http://www.jirben.wz.cz/ >.

Reference[edit | edit source]

Categorie:Hygiene Categorie:Occupational medicine Categorie:Toxicology Categorie:Pathobiochemistry