Sympathomimetic Toxicity Clinical Presentation

Updated: Mar 02, 2021
  • Author: Paul Kolecki, MD, FACEP; Chief Editor: Asim Tarabar, MD  more...
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Knowing that a sympathomimetic agent was ingested is helpful for treating a poisoned patient. Query patients about the use of cocaine, methamphetamine, and ecstasy. In addition, patients should be asked about their use of over-the-counter cold medications (containing ephedrine) and herbal preparations (eg, ephedra, Ma-Huang). Phenylpropanolamine used to be a very popular amphetamine sold over-the-counter; however, it was taken off the market by the US Food and Drug Administration (FDA) because of the risk of intracranial hemorrhage associated with its use. The FDA has also banned the sale of ephedra and ephedra-containing products, but those can be purchased over the Internet..

Maintain a high index of suspicion of sympathomimetic poisoning when treating an unknown overdose, especially in patients who present with the sympathomimetic toxidrome.

Another aid in the history of sympathomimetic poisoning is that the onset of symptoms usually occurs within 2 hours after exposure. Life-threatening complications typically occur within 2-6 hours postexposure.

Inadvertent exposure to methamphetamine can occur in buildings that have been used for the clandestine manufacture of the drug and have become contaminated with it. In 2015, an Australian family was found to have elevated methamphetamine levels and related adverse health effects after moving into a house that had previously been used as a methamphetamine drug laboratory and had not been decontaminated. Testing performed a year after police seized the laboratory showed dangerously elevated methamphetamine levels on surfaces within the home. [9]


Physical Examination

In adults, sympathomimetic toxicity produces typical adrenergic signs and symptoms, some of which can be deadly.

Bronchospasm and wheezing can occur in patients who smoke crack cocaine. In addition, crack cocaine use can cause asthma exacerbations, pneumothorax, and lung injury.

Hyperthermia associated with sympathomimetic toxicity may result from the violent behavior and extreme agitation experienced by these patients. The abuse of sympathomimetic agents in hot, humid environments (eg, dance clubs, summer evenings) can further exacerbate hyperthermia. Seizures resulting from overdose can also produce hyperthermia. Sympathomimetic-induced hyperthermia can produce significant morbidity (from end-organ damage) and death.

Extreme hypertension can result in headache, hypertensive encephalopathy, and intracranial hemorrhage. Sympathomimetic toxicity also can result in asymptomatic hypertension, which may require an urgent reduction in blood pressure.

The following cardiac arrhythmias may result from sympathomimetic toxicity:

  • Sinus and supraventricular tachycardia (including atrial fibrillation and atrial flutter)

  • Premature ventricular beats

  • Accelerated idioventricular rhythms, ventricular tachycardia, ventricular fibrillation, and torsade de pointes.

  • Second-degree and third-degree heart block (as a reflex response to hypertension)

  • Sympathomimetic-induced chest pain, myocardial ischemia, myocardial infarction, and cardiomyopathy (eg, from cocaine) also can occur. [10]

  • Seizures, strokes, and intracerebral bleeds are well-documented complications of sympathomimetic toxicity.

  • Dissecting thoracic aneurysms and mesenteric ischemia are rare but deadly consequences of sympathomimetic poisoning.

Nonlethal manifestations of sympathomimetic toxicity in adults include the following:

  • Mydriasis
  • Tachycardia
  • Diaphoresis
  • Acute psychosis
  • Paranoia
  • Delirium
  • Bruxism (amphetamines and bath salts)

Although pediatric sympathomimetic toxicity is not as well documented as adult toxicity, pediatric patients with sympathomimetic toxicity present with the same signs and symptoms observed in adults. Some pediatric patients with sympathomimetic toxicity initially presents with inconsolable crying, vomiting, and abdominal pain. These signs and symptoms are also the presenting features of many serious pediatric diseases (eg, sepsis, intussusception, intracranial lesion), so these patients may receive expensive ancillary tests to rule out significant disease.