eMedicine Specialties > Pediatrics: Cardiac Disease and Critical Care Medicine > Toxicology

Toxicity, Monoamine Oxidase Inhibitor: Differential Diagnoses & Workup

Author: Soumya Ganapathy, MD, Consulting Staff, Department of Emergency Medicine, Union Memorial Hospital
Coauthor(s): Frank A Maffei, MD, FAAP, Associate Professor of Pediatrics, Temple University School of Medicine; Director of Medical Student Affairs, Geisinger Health System; Pediatric Critical Care Attending Physician, Janet Weis Children's Hospital at Geisinger Medical Center
Contributor Information and Disclosures

Updated: Jan 23, 2008

Differential Diagnoses

Adrenal Insufficiency
Status Epilepticus
Diabetic Ketoacidosis
Thyroid Storm
Meningitis, Bacterial
Toxicity, Deadly in a Single Dose
Neuroleptic Malignant Syndrome
Toxicity, Iron
Pheochromocytoma
Sepsis

Other Problems to Be Considered

Ethanol withdrawal
Malignant hyperthermia
Sedative/hypnotic withdrawal
Serotonin syndrome
Heat stroke/heat exhaustion

Workup

Laboratory Studies

  • Rapid bedside glucose determination
  • ABG determination - Indicated if a compromise in oxygenation or ventilation is suspected
  • Lactate level - May be useful in phases 2 and 3 of an acute overdose to help determine end-organ perfusion
  • Determination of serum electrolyte, calcium, and magnesium levels - Calculation of the anion gap possibly helpful in screening for co-ingestions
  • Evaluation of serum acetaminophen and salicylate levels - Indicated in intentional overdoses
  • Screening for serum levels of alcohol (ethanol, methanol, isopropyl alcohol) - Indicated if alcohol ingestion is clinically suspected
  • Urine pregnancy test - Indicated in all women of childbearing age
  • Urinalysis and urine pH determination - May be useful in the setting of rhabdomyolysis
  • Urine drug screening - Comprehensive drug screening and screening for commonly abused drugs possibly helpful in assessing co-ingestions
  • Evaluation of levels of specific monoamine oxidase inhibitor (MAOI) drugs - Not readily available and, therefore, not clinically useful

Imaging Studies

  • Chest radiography is indicated if aspiration is a concern.
  • Perform postintubation chest radiography to evaluate the position of the endotracheal tube in relation to the carina if respiratory support is needed.

Other Tests

  • Sinus tachycardia is the most common ECG abnormality.
  • Nonspecific T-wave changes are also reported.

Procedures

  • Endotracheal intubation may be required.
    • Maintaining a stable airway is the most important step in the management of any toxic ingestion.
    • Intubation is required in any patient with a decreasing level of consciousness or signs of impending respiratory failure.
    • Secure the airway before administering activated charcoal or performing gastric lavage in patients with compromised mental status.
  • Venous access should be obtained.
    • Two large-bore peripheral intravenous lines should be placed in symptomatic patients.
    • Central access may be necessary for the infusion of vasoactive agents.
  • Gastric lavage is reserved for patients with life-threatening overdoses (2-3 mg/kg) who present within 1 hour of the ingestion.
    • A large-bore orogastric tube should be used.
    • Isotonic sodium chloride solution is preferred to water in young children because of the risk of an electrolyte imbalance and water intoxication.
    • Before proceeding with any decontamination, secure the patient's airway.
  • Foley catheterization of the bladder is indicated to assess urine output, especially in the setting of hemodynamic compromise or rhabdomyolysis.
  • Arterial line placement is indicated for continuous blood pressure monitoring and frequent blood sampling in patients with a severe ingestion and cardiovascular instability.

More on Toxicity, Monoamine Oxidase Inhibitor

Overview: Toxicity, Monoamine Oxidase Inhibitor
Differential Diagnoses & Workup: Toxicity, Monoamine Oxidase Inhibitor
Treatment & Medication: Toxicity, Monoamine Oxidase Inhibitor
Follow-up: Toxicity, Monoamine Oxidase Inhibitor
References
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References

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  2. Jarrott B, Vajda FJ. The current status of monoamine oxidase and its inhibitors. Med J Aust. Jun 15 1987;146(12):634-8. [Medline].

  3. Larsen JK. MAO inhibitors: pharmacodynamic aspects and clinical implications. Acta Psychiatr Scand Suppl. 1988;345:74-80. [Medline].

  4. Stewart JW, Thase ME. Treating DSM-IV depression with atypical features. J Clin Psychiatry. Apr 2007;68(4):e10. [Medline].

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  6. Dilsaver SC. Monoamine oxidase inhibitor withdrawal phenomena: symptoms and pathophysiology. Acta Psychiatr Scand. Jul 1988;78(1):1-7. [Medline].

  7. Feinberg SS. Combining stimulants with monoamine oxidase inhibitors: a review of uses and one possible additional indication. J Clin Psychiatry. Nov 2004;65(11):1520-4. [Medline].

  8. Frazer A, Conway P. Pharmacologic mechanisms of action of antidepressants. Psychiatr Clin North Am. Sep 1984;7(3):575-86. [Medline].

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  15. Siberry GK, Iannone R, eds. The Harriet Lane Handbook. In: A Manual for Pediatric House Officers. 15th ed. Mosby-Year Book: 2000.

  16. Siderowf A, Kurlan R. Monoamine oxidase and catechol-O-methyltransferase inhibitors. Med Clin North Am. Mar 1999;83(2):445-67. [Medline].

  17. Tollefson GD. Monoamine oxidase inhibitors: a review. J Clin Psychiatry. Aug 1983;44(8):280-8. [Medline].

  18. Wax P, Hoffman J, Keyes CD. Neuroleptics, lithium, and monoamine oxidase inhibitors. In: Rosen P, Barkin R, eds. Emergency Medicine. 3rd ed. 1992:2624-2628.

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Further Reading

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Keywords

monoamine oxidase inhibitor, antidepressant overdose, antidepressant poisoning, antidepressant overdoses, antidepressant poisonings, antidepressant-induced hepatotoxicity, childhood ingestions, MAO antidepressant, MAO antidepressant overdose, MAO antidepressant toxicity, MAO antidepressant poisoning, MAOI, MAOIs, MAOI overdose, MAOI toxicity, MAOI poisoning, monoamine oxidase A, MAO-A, monoamine oxidase B, MAO-B, phenelzine, tranylcypromine, isocarboxazid, Parkinson disease, methicillin-resistant Staphylococcus aureus, hypertension, tachycardia, hyperpexia, mydriasis, diaphoresis, rhabdomyolysis, renal failure, pulmonary edema, myocardial infarction, disseminated intravascular coagulopathy, serotonin syndrome

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Contributor Information and Disclosures

Author

Soumya Ganapathy, MD, Consulting Staff, Department of Emergency Medicine, Union Memorial Hospital
Soumya Ganapathy, MD is a member of the following medical societies: American College of Emergency Physicians
Disclosure: Nothing to disclose.

Coauthor(s)

Frank A Maffei, MD, FAAP, Associate Professor of Pediatrics, Temple University School of Medicine; Director of Medical Student Affairs, Geisinger Health System; Pediatric Critical Care Attending Physician, Janet Weis Children's Hospital at Geisinger Medical Center
Frank A Maffei, MD, FAAP is a member of the following medical societies: American Academy of Pediatrics
Disclosure: Nothing to disclose.

Medical Editor

Michael E Mullins, MD, Assistant Professor, Department of Emergency Medicine, Washington University School of Medicine
Michael E Mullins, MD is a member of the following medical societies: American Academy of Clinical Toxicology and American College of Emergency Physicians
Disclosure: Nothing to disclose.

Pharmacy Editor

Mary L Windle, PharmD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy, Pharmacy Editor, eMedicine.com, Inc
Disclosure: Pfizer Inc Stock Investment from broker recommendation; Avanir Pharma Stock Investment from broker recommendation

Managing Editor

Jeffrey R Tucker, MD, Assistant Professor, Department of Pediatrics, Division of Emergency Medicine, University of Connecticut and Connecticut Children's Medical Center
Jeffrey R Tucker, MD is a member of the following medical societies: American Academy of Clinical Toxicology, American Academy of Pediatrics, and Massachusetts Medical Society
Disclosure: Nothing to disclose.

CME Editor

Paul D Petry, DO, FACOP, FAAP, Clinical Assistant Professor of Pediatrics, University of North Dakota, School of Medicine and Health Sciences; Consulting Staff, Altru Health System
Paul D Petry, DO, FACOP, FAAP is a member of the following medical societies: American Academy of Osteopathy, American Academy of Pediatrics, American College of Osteopathic Pediatricians, and American Osteopathic Association
Disclosure: Nothing to disclose.

Chief Editor

Timothy E Corden, MD, Associate Professor of Pediatrics, Co-Director, Policy Core, Injury Research Center, Medical College of Wisconsin; Associate Director, PICU, Children's Hospital of Wisconsin
Timothy E Corden, MD is a member of the following medical societies: American Academy of Pediatrics, Phi Beta Kappa, Society of Critical Care Medicine, and Wisconsin Medical Society
Disclosure: Nothing to disclose.

 
 
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