POISONING OR OVERDOSE
Patients with drug overdoses or poisoning may initially have no symptoms or they may have varying degrees of overt intoxication. The asymptomatic patient may have been exposed to
or may have ingested a lethal dose of a poison but not yet have any manifestations of toxicity.
It is always important to:
quickly assess the potential danger,
perform gut decontamination to prevent absorption,
observe the patient for an appropriate interval.
Assess the Danger
If the toxin is known, the danger can be assessed by consulting a text or computerized information resource or by calling a regional poison control center. Assessment will usually take into account the dose ingested (in milligrams per kilogram of body weight); the time interval since ingestion; the presence of any clinical signs; preexisting cardiac, respiratory, renal, or liver disease; and, occasionally, specific serum drug or toxin levels. Be aware that the history given by the patient or family may be incomplete or unreliable.
The manufacturer or its local representative may be able to provide information over the phone concerning the toxic ingredients in question and can be contacted directly or via the regional poison control center.
The choice of gut decontamination procedure depends on the toxin and the circumstances.
Observation of the Patient
Asymptomatic or mildly symptomatic patients should be observed for at least 4–6 hours. Longer observation is indicated if the ingested substance is a sustained-release preparation or is known to slow gastrointestinal motility or if there may have been exposure to a poison with delayed onset of symptoms (such as acetaminophen, colchicine, or hepatotoxic mushrooms). After that time, the patient may be discharged if no symptoms have developed and adequate gastric decontamination has been provided. Before discharge, psychiatric evaluation should be performed to assess suicidal risk. Intentional ingestions in adolescents should raise the possibility of unwanted pregnancy or sexual abuse.
THE SYMPTOMATIC PATIENT
In symptomatic patients, treatment of life-threatening complications takes precedence over in-depth diagnostic evaluation. Patients with mild symptoms may deteriorate rapidly, which is why all potentially significant exposures should be observed in an acute care facility. The following complications may occur, depending on the type of poisoning.