eMedicine Specialties > Neurology > Neurotoxicology

Organophosphates: Follow-up

Author: Frances M Dyro, MD, Chief of the Neuromuscular Section, Associate Professor, Department of Neurology, New York Medical College, Westchester Medical Center
Contributor Information and Disclosures

Updated: Oct 12, 2009

Follow-up

Further Inpatient Care

Following treatment of the acute manifestations of organophosphate poisoning, patients may develop tremor, cognitive deficits, and general debility; they may need treatment of these secondary consequences of organophosphate toxicity. In the case of the patient exposed to large amounts of diazinon, the effects initially were thought to be seizures but were in fact related to generalized nervous system hyperexcitability, which the author treated with tizanidine (Zanaflex).

Further Outpatient Care

  • Generally, after the treatment of acute effects of organophosphate exposure, no additional treatment is needed. Occasionally, the patient has residual neurophysiologic and neuropsychological sequelae.
  • Patients exposed to an agent suspected of producing neuropathy require monitoring and electrodiagnostic studies several weeks following acute toxicity.
  • Neuropsychological assessment on a periodic basis is recommended for workers with long-term exposure.
  • Testing should be done for patients with complaints of memory problems and cognitive deficits.

Inpatient & Outpatient Medications

Generally, no medications are prescribed for the patient at discharge.

Transfer

Transfer to a rehabilitation facility may be indicated for the patient who develops late neuropathic sequelae.

Deterrence/Prevention

  • Use of pesticides in enclosed spaces generally results in exposure to organophosphates. Use of proper ventilation and avoidance of cutaneous exposure reduces toxic events. Many of the more toxic substances are being phased out of production. Carbamate pesticides, for example, while not totally benign, cause a less severe type of toxicity. The carbamates are cholinesterase inhibitors with a blockade time of about 6 hours. They do not cross the blood-brain barrier well and affect primarily the peripheral receptors.
  • Care must be taken by those who use organophosphate pesticides commercially (eg, crop dusters, farmers); a healthy respect for the substances will help reduce cases of acute toxicity.
  • Children should be kept from areas where pesticides have been applied.

Complications

Complications generally are seen during the period of hospitalization and involve respiratory difficulty, requiring intubation and ventilatory assistance. Seizures occurring during the acute phase should be treated with diazepam.

Prognosis

  • Promptly treated organophosphate toxicity carries a favorable prognosis.
  • Individuals with long-term exposure need to be monitored for the late complication of neuropathy and development of cognitive abnormalities.

Patient Education

  • Pesticides can be dangerous substances if used improperly. They must be kept in a safe place and away from children. People using pesticides should be educated in the fact that the chemicals can enter the body by several routes and to use gloves, protective clothing, and even respiratory protection. After cutaneous exposure, immediate washing is a must.
  • Patients exposed to pesticides at home should be cautious concerning the potential for repeat exposure. Individuals need to have proper ventilation and to use personal protective equipment such as plastic gloves and clothing that can be removed and laundered immediately after spraying is completed.
  • Employers are required to provide protective equipment and to instruct their workers to avoid undue exposure by not applying pesticides downwind on a windy day.

Miscellaneous

Medicolegal Pitfalls

  • The patient presenting acutely in an agitated state may not be able to give a clear history of what happened. The wheezing, tightness in the chest, and weakness may simulate an asthmatic attack. If possible, the container of the substance to which the patient was exposed should be brought to the hospital. Treatment with atropine and pralidoxime must be initiated immediately after the condition is diagnosed.
  • The patient's response to the initial treatment may give a false sense of security; therefore, the patient should not be discharged until the effect of the organophosphate clearly has been totally reversed.
  • Since many people susceptible to organophosphate toxicity are in work-related situations, workmen's compensation issues may arise.
  • Many highly toxic pesticides have been removed from the market. However, some of these may be still in use.
  • Failure to arrange for careful follow-up to monitor late complications can result in a possible medicolegal action.

Special Concerns

  • All toxic substances should be stored out of the reach of children.
  • Exposure during pregnancy should be avoided.
 


More on Organophosphates

Overview: Organophosphates
Differential Diagnoses & Workup: Organophosphates
Treatment & Medication: Organophosphates
Follow-up: Organophosphates
Multimedia: Organophosphates
References
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Further Reading

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Keywords

organophosphates, nerve agent, pesticides, organophosphate insecticides, diazinon, disulfoton, azinphos-methyl, fonofos, therapeutic use of organophosphates, toxic nerve agents, sarin, neurotoxicity

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Contributor Information and Disclosures

Author

Frances M Dyro, MD, Chief of the Neuromuscular Section, Associate Professor, Department of Neurology, New York Medical College, Westchester Medical Center
Frances M Dyro, MD is a member of the following medical societies: American Academy of Neurology, American Association of Neuromuscular and Electrodiagnostic Medicine, and Muscular Dystrophy Association
Disclosure: Nothing to disclose.

Medical Editor

Jonathan S Rutchik, MD, MPH, Assistant Professor, Department of Occupational and Environmental Medicine, University of California at San Francisco
Jonathan S Rutchik, MD, MPH is a member of the following medical societies: American Academy of Neurology, American Association of Neuromuscular and Electrodiagnostic Medicine, American College of Occupational and Environmental Medicine, and Society of Toxicology
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: eMedicine Salary Employment

Managing Editor

Neil A Busis, MD, Chief, Division of Neurology, Department of Medicine, Head, Clinical Neurophysiology Laboratory, University of Pittsburgh Medical Center-Shadyside
Neil A Busis, MD is a member of the following medical societies: American Academy of Neurology and American Association of Neuromuscular and Electrodiagnostic Medicine
Disclosure: Nothing to disclose.

CME Editor

Selim R Benbadis, MD, Professor, Director of Comprehensive Epilepsy Program, Departments of Neurology and Neurosurgery, University of South Florida School of Medicine, Tampa General Hospital
Selim R Benbadis, MD is a member of the following medical societies: American Academy of Neurology, American Academy of Sleep Medicine, American Clinical Neurophysiology Society, American Epilepsy Society, and American Medical Association
Disclosure: Nothing to disclose.

Chief Editor

Stephen A Berman, MD, PhD, Professor, Department of Internal Medicine, Section of Neurology, Dartmouth Medical School; Chief, Neurology Service, White River Junction Veterans Medical Center
Stephen A Berman, MD, PhD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Neurology, and Phi Beta Kappa
Disclosure: Nothing to disclose.

 
 
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