Patients with toxicologic exposures commonly present to the emergency department (ED). Many toxicologic patients need a period of observation to have their needs fully met. Problems associated with the more common toxicological exposures reside in two areas, which are discussed in this article.

The first area is medical issues relating to adverse effects on the patient from the toxicologic exposure. The patient needs to be assessed for evidence of toxicity, complications of toxicity, and exacerbation of an underlying medical disorder resulting from the exposure. Patients who are asymptomatic, but at risk for potential effects because they had a significant exposure, need careful evaluation. Patients exposed to substances with delayed effects, such as oral hypoglycemics and sustained-release cardiac preparations, may need observation services to ensure they do not develop delayed complications. These patients require serial re-evaluation and expectant management. Complications of their exposure need to be treated with interveneous (IV) fluids and appropriate medications. Patients with more serious complications of their exposures at the time of ED evaluation (e.g., aspiration pneumonia, rhabdomyolysis, and wound infections) should be admitted to the hospital rather than observed because management is involved and the time course usually is longer than 24 hours. Patients with an exacerbation of their underlying medical illness can often be managed in the observation unit (OU), but this is dependent on the nature of their illness (e.g., an asthma exacerbation from chlorine exposure may be treatable in the 10–12 hour average of an OU visit). Patients with evidence of end-organ damage (disorders related to the cardiovascular, renal, central nervous system, [CNS], and respiratory systems) resultant from their toxicity usually, require hospital admission. Those patients with criteria for admission to an intensive care unit (ICU) are not candidates for observation (e.g., intubation, seizures, cardiac dysrhythmias, hypotension, comatose, tricyclic overdose with anticholinergic signs, neurologic abnormality, or prolonged QRS duration). When it is unclear to the emergency physician what the most appropriate management plan for the patient, should entail, the emergency physician may consult with the regional poison center or medical toxicologist. Patients appropriate for transfer to the OU have medical issues that cannot be fully addressed in the ED and it is not clear they need an acute care hospitalization.

The second area is psychiatric issues relating to how the patient received the toxicologic exposure. Many psychiatric patients will have intentionally exposed themselves because they are depressed and suicidal. Some of these patients were accidentally exposed to the toxic substance. The patient's emotional and psychiatric status needs to be assessed. Issues of safety in the patient's home (especially with children) or safety in the workplace may need to be addressed. A period of observation with consultation to psychiatry may be necessary before the physician can make a final decision on hospital admission or patient release.

Patient evaluation and management varies greatly depending on the type of toxicologic exposure. Most of the remainder of this article is devoted to examining the specific categories of toxicologic exposures.