Drugs of abuse continue to have a significant impact on healthcare utilization in the pediatric population. The pediatric hospitalist should consider drugs of abuse in the differential diagnosis of any patient who presents with altered mental status (hallucinations, stupor, coma), abnormal motor activity (tremor, seizure), or behavioral disturbance (agitation, outburst, withdrawal, depression, suicidal or homicidal ideation).

Each fall, the American Association of Poison Control Centers publishes its annual summary of poisoning exposures reported to its member centers. In 2011, there were a total of 2.3 million exposures reported, 1158 of which led to a fatality.¹ Of these fatalities, 41 (3.5%) involved a child (<20 years of age) who intentionally abused (alone or in combination with other substances) cannabinoids, hallucinogens, inhalants, narcotics, or stimulants (Table 169-1).

Another annual resource is the National Institute on Drug Abuse’s Monitoring the Future surveys of eighth-, tenth-, and twelfth-grade students conducted to gauge trends in drug use as well as levels of perceived risk and disapproval among these children. First performed in 1975, the most recent of these extensive studies is in the public domain and posted on the organization’s website.² The 2012 survey reached 45,000 students in 395 secondary schools. Compared to the prior year’s survey, there were no significant changes in the rate of use of most illicit drugs; however, there were statistically significant declines in the use of ecstasy (MDMA) and heroin (without a needle). Prescription narcotic analgesics are a class of significant concern, although the data have indicated a slight decrease in the use of Vicodin (hydrocodone/acetaminophen) and OxyContin (controlled-release oxycodone).

Initial assessment of a patient who may have been exposed to any drugs of abuse follows the principles outlined in Chapter 165. Reassessment should occur periodically, even in patients who appear to be stable on initial evaluation; if drug absorption and distribution are not complete at the time of presentation, the clinical condition may worsen with the passage of time.

After the initial assessment, the hospitalist should attempt to elicit a complete history from the patient, if lucid and cooperative, or from a parent, guardian, or other companion who may be able to provide details of the exposure. Pre-hospital personnel may be able to shed additional light, particularly if pill containers or other items are available at the scene.

A thorough history often elicits clues about specific drugs of abuse. A number of surveys around the world have documented the use of illicit drugs in various populations and social settings. For example, a survey in the United Kingdom identified risk taking, male gender, higher educational level, single marital status, unemployment, age younger than 25 years, smoking, and heavy alcohol (ethanol) consumption among the social factors associated with the use of these drugs.³ In a Taiwanese survey of 54,000 school-attending adolescents in grades 7, 9, 10, and 12, “ecstasy” (methylenedioxymethamphetamine, or MDMA) was found to replace methamphetamine as the most commonly used illegal drug in that country. However, ecstasy use appeared to decrease in prevalence and incidence over the study period (2004-2006), while ketamine use increased.⁴ Data obtained from a randomly selected sample of 11,000 college students in 119 colleges in the United States revealed that 4.1% of these students reported illicit consumption of stimulant medications commonly used as treatment for attention deficit hyperactivity disorder (methylphenidate, dextroamphetamine, or mixed amphetamine formulations) in the previous year. Of note, the nonmedical uses of these medications, which are often used as study aids, were more common at colleges located in the northeast United States that had more competitive admission standards.⁵ A decade-long series of surveys of psychotropic drug use among 10- to 18-year-old Brazilian students revealed significant increases over the study period in the use of many drugs, including amphetamines, anxiolytics, cocaine, and marijuana.⁶ Another survey of school athletes in five European Union countries (Finland, France, Germany, Greece, Italy) plus Israel⁷ documented their use of illicit substances, including those that the International Olympic Committee (IOC) lists as banned “doping agents:” anabolic agents, peptide hormones, corticosteroids, diuretics, stimulants, narcotics, cannabinoids, and beta-blockers. First published in 1963 under the leadership of the IOC, the “prohibited list” of banned agents now falls under the aegis of the World Anti-Doping Agency.⁸

Injuries may be associated with drugs of abuse because risk seeking is a closely linked behavior and judgment is often impaired while under the influence of drugs. An individual who attempts to operate a motor vehicle while under the influence of drugs or ethanol (or both) is at increased risk for crashes and resultant trauma. Researchers in the Netherlands conducted a case control study in which blood samples of drivers hospitalized after crashes were compared with those randomly recruited on the roads. This study population demonstrated a concentration-dependent increase in motor vehicle crash risk for those subjects who used cannabis. The risk of a crash at a THC concentration of 2 ng/mL or greater was significantly increased. Risk of a crash was also increased with the use of amphetamines. Drivers who used ethanol alone, or a combination of ethanol and other drugs, had a very elevated crash risk; however, the highest risk was associated with combined stimulant and sedative use.⁹ Ethanol presents an interesting problem because it is so broadly tolerated in a social context, yet can be considered a drug of abuse that accounts for significant morbidity/mortality. For example, ethanol has an effect on slow eye movements, the basis for horizontal gaze nystagmus that law enforcement officials may observe in field sobriety tests. Recent work suggests that this effect leads to impaired “motion parallax” and depth perception.¹⁰ The epidemic of methamphetamine abuse deserves special note; this highly addictive drug causes significant morbidity and mortality, but it also creates a significant environmental hazard to children exposed to its clandestine production.^11,12

Exposure to drugs of abuse often occurs at bars, parties, or rave dances, and in such cases “club” drugs such as MDMA or ketamine, and “date rape” drugs such as flunitrazepam (Rohypnol) or gamma hydroxybutyric acid (GHB) should be suspected (see discussion in Diagnosis and Evaluation).

The clinician should also be aware of newer classes of drugs of abuse, such as synthetic cannabinoids (“K2” or “Spice”) and the synthetic cathinones, stimulants often referred to as “bath salts.” While initially inexpensive and widely available over the Internet and at local gas stations and convenience stores, use of these substances in the United States likely peaked around 2011. Undetectable by commonly used serum and urine drug screens, users believed that these substances were effective as a “legal high.” However, the Synthetic Drug Abuse Prevention Act of 2012 added both synthetic cannabinoids and cathinones to the Schedule I controlled substance list.¹³

Patients suspected of intentional or unintentional exposure to drugs of abuse may present with symptom/sign complexes or toxic syndromes (toxidromes) that suggest a specific drug class. Commonly abused drugs and related symptoms and signs are listed in Table 169-2.