thiamine deficient secondary to eating disorders, chronic disease (e.g., inflammatory bowel disease), or alcoholism The rationale for decontamination (D econtamination) of the poisoned child is discussed in the next section This treatment phase may begin urgently, after or in concert with attention to the ABCDs At times, a decision to perform gastric decontamination through the preferred technique can be made almost immediately upon presentation and, if so, should be instituted as soon as possible, taking into account the patient’s clinical status For example, a toddler with coma, shock, and massive hematochezia who is rushed into the ED by the rescue squad —and for whom there is witnessed or strong circumstantial evidence of massive iron overdose—requires a concerted team effort directed toward resuscitation, stabilization, and urgent gastric decontamination However, an asymptomatic adolescent who ingests 10 g of acetaminophen 30 minutes before arrival at the ED may be fully evaluated in a timely but orderly manner (as outlined in the next section) and considered for less emergent gastric decontamination—in this case, possibly an oral dose of activated charcoal Significant dermal or ocular exposures require immediate copious lavage, and precautions should be taken to protect healthcare providers from exposure At the completion of this initial life support phase, the poisoned patient should have been assessed for compromise of vital airway and cardiorespiratory function and for global neurologic status and should have had resuscitative measures instituted Patients with significant altered mental status have been critically evaluated for respiratory status, have had IV access secured, and have had therapeutic trials of oxygen, glucose, and naloxone Other advanced life support interventions such as anticonvulsants or antiarrhythmics have been instituted as necessary Consideration of decontamination options has begun Evaluation and Detoxification Phase History A brief and focused historical evaluation should be addressed as soon as the life support phase has been completed The primary goal is to determine the potential severity of the exposure, which requires information about both the poison and the patient For a known or highly suspected toxic exposure, attempt to estimate the total amount ingested (number of pills missing, ounces left in the bottle, dosage of pills, concentration of alcohol, and so forth) Also attempt to determine the best estimate of time elapsed since ingestion Ask about early symptoms noted at home or en route to the ED and any treatments administered before arrival Certain underlying medical conditions may be relevant (e.g., glucose-6-phosphate dehydrogenase [G6PD] deficiency for mothball ingestions); thus, any significant medical history should be noted Often, children who are poisoned not come to the ED with a clear history of exposure followed by onset of symptoms Rather, they develop signs and symptoms that mimic other diseases and give no history of toxic exposure Thus, the ED staff must always consider the possibility of ingestion when treating young children General historical features that suggest the possibility of poisoning include (i) acute onset; (ii) age range of to years or adolescence; (iii) history of pica or known exposure to a potential toxicant; (iv) substantial environmental stress, either acute (e.g., arrival of a new baby, serious illness in a parent) or chronic (e.g., marital conflict, parental disability); (v) multiple organ system involvement; (vi) significant alteration in level of consciousness; and (vii) a clinical picture that seems especially puzzling Certain family and social history variables are also important Medications used by other household members, particularly new medications introduced into the home environment by virtue of recent illnesses, or visits from/to grandparents and other relatives, are a common source of ingested drugs Changes in routine and large family gatherings (e.g., holiday parties, moving to a new home) are particularly risky occasions for decreased parental supervision or less carefully guarded potentially toxic medications or household products Although often difficult to obtain, the history of illicit drug use, manufacture, or distribution in the child’s environment (the “drug-endangered child”) significantly increases the risk of serious outcomes from a poison exposure as well Physical Examination The focused physical examination should begin with a reassessment of vital functions and complete recording of vital signs, including core temperature After securing the airway and ensuring adequate cardiorespiratory function, focus on the central and autonomic nervous systems, eye findings, changes in the skin and/or oral and gastrointestinal (GI) mucous membranes, and odors (see Chapter 50 Odor: Unusual ) on the breath or clothing of the patient These features represent those areas most likely affected in toxic syndromes and, when taken together, often form a constellation of signs and symptoms referred to as toxidromes ( Tables 102.5 and 102.6 ) Such toxidromes may be so characteristic as to provide guidance for early therapeutic management before precise historical or laboratory confirmation of a specific exposure is available Laboratory Evaluation Laboratory studies may be helpful in confirming diagnostic impressions or in demonstrating toxicant-induced metabolic aberrations However, there is no “tox panel” that is uniformly helpful or necessary Most poisonings can be managed appropriately without extensive laboratory studies, and in particular, the reflex ordering of rapid overdose toxicology screens is rarely helpful in acute patient management They may have important, nonemergent roles (e.g., in resolving medicolegal issues or considering drug-induced causes of behavioral changes in a psychiatric patient) In toddlers with a known or strongly suspected specific ingestion, rapid drug screens are rarely indicated In the adolescent intentional overdose patient who is not critically ill or who does not have a particularly puzzling clinical picture, the drug screen is rarely helpful, although adolescents may ingest multiple drugs and may not be truthful Therefore, some authors recommend serum levels of acetaminophen and salicylates, two of the most common treatable co-ingestants The comprehensive urine drug screen may rarely be useful for seriously ill patients with an occult ingestion, or for the intentional overdose adolescent patient whose clinical picture does not fit with the stated history Often more helpful is the critical interpretation of routine measurements of serum chemistries, blood gas analysis, and osmolality in patients with altered mental status The presence of hypoglycemia or aberrations of serum electrolytes may provide crucial information about the poisoned patient In certain circumstances, tests of liver or renal function, urinalysis, creatine phosphokinase levels, and other select tests may be useful Metabolic acidosis with a high anion gap is found in many clinical syndromes and toxidromes, reflected by the oftencited mnemonic MUDPILES, for m ethanol and m etformin; u remia; d iabetic and other ketoacidoses; p araldehyde and p aracetamol (acetaminophen); i soniazid (INH), i ron, i nborn errors of metabolism and massive i buprofen; l actic acidosis (seen with hypoxia, shock, carbon monoxide, cyanide, and many drugs that cause compromised cardiorespiratory status or prolonged seizures); e thylene glycol; and s alicylates or s eizures Differences between calculated and measured serum osmolarity (calculated = [serum Na mEq per L] + blood urea nitrogen [BUN] mg per dL ÷ 2.8 + glucose mg per dL ÷ 18; with normal osmolarity ∼290 mOsm/kg) may suggest intoxication with ethanol, isopropanol, or more rarely in pediatric patients, methanol or ethylene glycol Do not use blood collection tubes containing ethylenediaminetetraacetic acid (EDTA) because the osmolal gap will be falsely elevated TABLE 102.5 CLINICAL MANIFESTATIONS OF POISONING ... osmolarity ∼290 mOsm/kg) may suggest intoxication with ethanol, isopropanol, or more rarely in pediatric patients, methanol or ethylene glycol Do not use blood collection tubes containing ethylenediaminetetraacetic