46: Toxic Ingestions & Exposures

GENERAL MANAGEMENT OF THE INTOXICATED PATIENT

POISON CONTROL CENTERS

Poison control centers were developed to provide immediate advice from trained specialists in poison information to aid in the management of poisonings. In the United States, 1(800) 222-1222 is the nationwide toll-free number to a regional poison center. A clinical toxicologist is available to provide expert consultation.

PRINCIPLES OF MANAGEMENT OF THE POISONED PATIENT

PATIENT EVALUATION

History

Obtaining an accurate history is of critical importance.

Nature of the Toxin(s)

Obtain the trade, brand, generic, or chemical name(s). It is important to be precise because products with similar names may have different compositions. Concentrations or amounts of various constituents from the label are useful. Unknown tablets and capsules can frequently be identified from the imprint code on the item along with the color and shape.

Magnitude of Exposure

Estimate the volume of liquid or number of tablets or capsules ingested. In cases of intentional ingestion, the history can be inaccurate, frequently underestimating the amount and the nature of what has been consumed. When the exact amount ingested is not known, it is prudent to manage the patient according to the worst-case scenario.

Time of Exposure

Signs and symptoms of toxicity usually occur within a few hours of ingestion for most overdoses. However, some poisons demonstrate delayed onset of toxicity. Examples of delayed toxicity include acetaminophen, methanol, ethylene glycol, and modified-release pharmaceuticals.

Progression of Symptoms

The severity and progression of toxicity are determinants of the need for therapy.

Other Medical Conditions (both acute and chronic)

Preexisting medical conditions may increase susceptibility to a specific toxin. Unwanted pregnancy may precipitate an attempted suicide. In addition, the effect of the toxin on the fetus should be considered.

TOXIDROMES

Toxidromes are toxic syndromes (characteristic signs and symptoms caused by a particular toxin) and may facilitate diagnosis when the toxin is unknown. They are also useful for anticipating signs and symptoms that are likely to occur when the toxin is known. Table 46–1 describes commonly encountered toxidromes.