Diagnostic Considerations

Although organophosphate toxicity results in decreased cholinesterase, falsely depressed levels of red blood cell cholinesterase can be found in the following cases:

Pernicious anemia
Hemoglobinopathies
Use of antimalarial drugs
Blood collection tubes containing oxalate

Falsely depressed levels of plasma cholinesterase are observed in the following cases:

Liver dysfunction
Low-protein conditions
Neoplasia
Hypersensitivity reactions
Use of certain drugs (eg, succinylcholine, codeine, morphine)
Pregnancy
Genetic deficiencies

Other problems to be considered in the differential diagnosis of organophosphate toxicity include the following:

Carbamate toxicity
Nicotine toxicity
Carbachol toxicity
Methacholine toxicity
Arecoline toxicity
Bethanechol toxicity
Pilocarpine toxicity
Pyridostigmine toxicity
Neostigmine toxicity
Mushroom poisoning ( Clitocybe, Inocybe)
Poison hemlock ( Conium maculatum)poisoning
Myasthenia gravis
Eaton-Lambert syndrome
Guillain-Barré syndrome
Botulism
Eclampsia

Differential Diagnoses

Toxicity, Mushroom
Viral Gastroenteritis

Workup

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Author

Kenneth D Katz, MD, FAAEM, ABMT Assistant Professor, Division of Medical Toxicology, Department of Emergency Medicine, University of Pittsburgh Medical Center; Medical Director, Pittsburgh Poison Center

Kenneth D Katz, MD, FAAEM, ABMT is a member of the following medical societies: American Academy of Emergency Medicine, American College of Medical Toxicology

Disclosure: Nothing to disclose.

Coauthor(s)

Daniel E Brooks, MD Co-Medical Director, Banner Good Samaritan Poison and Drug Information Center, Department of Medical Toxicology, Banner Good Samaritan Medical Center

Daniel E Brooks, MD is a member of the following medical societies: American Academy of Clinical Toxicology, American College of Emergency Physicians, American College of Medical Toxicology

Disclosure: Nothing to disclose.

Specialty Editor Board

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Received salary from Medscape for employment. for: Medscape.

Chief Editor

Sage W Wiener, MD Assistant Professor, Department of Emergency Medicine, State University of New York Downstate Medical Center; Director of Medical Toxicology, Department of Emergency Medicine, Kings County Hospital Center

Sage W Wiener, MD is a member of the following medical societies: American Academy of Clinical Toxicology, American Academy of Emergency Medicine, American College of Medical Toxicology, Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

Additional Contributors

Lisa Kirkland, MD, FACP, FCCM, MSHA Assistant Professor, Department of Internal Medicine, Division of Hospital Medicine, Mayo Clinic; Chair, Department of Critical Care, ANW Intensivists, Abbott Northwestern Hospital

Lisa Kirkland, MD, FACP, FCCM, MSHA is a member of the following medical societies: American College of Physicians, Society of Critical Care Medicine, Society of Hospital Medicine

Disclosure: Nothing to disclose.

Acknowledgements

The authors and editors of Medscape Reference gratefully acknowledge the contributions of previous authors Marina C Furtado, MD, and Lisa Chan, MD, FACEP, to the development and writing of this article.

Organophosphate Toxicity Differential Diagnoses

Diagnostic Considerations

Differential Diagnoses

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