Approach to the Poisoned Patient

Initial ApproachTop

First contact: As in all acutely ill patients, in individuals with poisoning the maintenance of airway, breathing, and circulation (ABC) is the priority. Decontamination, if applicable, is the next step that may even precede treatment (to avoid continuous patient’s exposure and to avoid contaminating the hospital staff or the entire facility [eg, in the case of organophosphate overdose]). A detailed history and physical examination are frequently required to identify the offending agents. Some signs and symptoms of toxicity as well as syndromes or odors are specific for certain agents and aid in narrowing down differential diagnosis. Cardiac function should be monitored in all patients.

Diagnosis and ManagementTop

1. Initial diagnostic workup:

1) Blood glucose levels.

2) Complete blood count (CBC), electrolyte levels, serum osmolality and creatinine.

3) Blood gas analysis (arterial or venous).

4) Electrocardiography (ECG).

5) Serum acetaminophen (INN paracetamol) and salicylate levels.

6) Urine drug screen (for certain toxins, if the history is suggestive).

7) Serum levels of alcohol and/or suspected drugs (if applicable).

8) Pregnancy testing if the history of pregnancy is unclear.

2. Decontamination methods:

1) Ipecac: Ipecac is no longer recommended by the European and North American toxicology associations (no evidence of efficacy).

2) Activated charcoal (AC): Current guidelines do not recommend routine AC administration. The potential benefit of this drug decreases rapidly if administered >60 minutes after ingestion of a toxin or poison. It may be of benefit if the poisoning involves drugs with delayed gastric emptying (eg, opioids, sustained-release drugs, or drug “packers” and “stuffers” [smuggling drugs in body cavities]). In the case of certain drugs patients may benefit from early and multiple doses of AC (eg, carbamazepine, acetylsalicylic acid [ASA], phenobarbital, theophylline). However, certain toxins are not affected by AC (acids, alkalis, metals, alcohol, hydrocarbons).

The use of AC is not without risks, which include pulmonary aspiration in obtunded patients with oral or nasogastric tube administration.

There is no supporting evidence for the use of cathartic drugs, such as sorbitol, with AC and they should be avoided.

3) Whole-bowel irrigation (WBI): WBI consists of rapid administration of polyethylene glycol electrolyte solution to produce liquid stools, allowing for elimination of tablets or drug packets from the gastrointestinal tract. It is not recommended routinely but may be helpful in situations involving sustained-release preparations or insertion of packs of drugs into body cavities. While WBI may be useful in clearing medication bezoars, it is contraindicated in patients with intestinal obstruction or bowel perforation.

4) Gastric lavage (GL): GL is a procedure where a large-bore orogastric tube is inserted with intent to aspirate tablets or fragments of pills from the stomach following an acute ingestion. This procedure requires airway protection and carries a risk of major complications including aspiration or esophageal rupture. It can be used in rare situations when experienced personnel are available and ingestion is potentially lethal.

Poison CentersTop

Contact details of Canadian poison control centers: safemedicationuse.ca.