poisonings

Poisonings  

Zachary Nayak MD

 and Jocelyn Ronda MD

Harriet Lane Handbook, The, Chapter 2, 19-26

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I

Websites

American Association of Poison Control Centers: http://www.aapcc.org/dnn/Home.aspx

American Academy of Clinical Toxicology: http://www.clintox.org/index.cfm

Centers for Disease Control and Prevention, Section on Environmental Health:http://www.cdc.gov/Environmental/

II

Initial Evaluation

A. 

History

&lt1. 

Exposure history

a. 

Obtain history from witnesses and/or close contacts.

b. 

Route, timing, and number of exposures (acute, chronic, or repeated ingestion), prior treatments or decontamination efforts. ¹²

&lt2. 

Substance identification

a. 

Attempt to identify exact name of substance ingested and constituents, including product name, active ingredients, possible contaminants, expiration date, concentration, and dose.

b. 

Consult local poison control for pill identification: 1-800-222-1222.

&lt3. 

Quantity of substance ingested

a. 

Attempt to estimate a missing volume of liquid or the number of missing pills from a container.

&lt4. 

Environmental information

a. 

Accessible items in the house or garage; open containers; spilled tablets; household members taking medications, herbs, or other complementary medicines. ²

B. 

Laboratory Findings

&lt1. 

Toxicology screens : Includes amphetamines, barbiturates, cocaine, ethanol, and opiates ( Table 2-1 ).

a. 

If a particular type of ingestion is suspected, verify that the agent is included in the toxicology test . ²

b. 

When obtaining a urine toxicology test, consider measuring both aspirin and acetaminophen blood levels because these are common analgesic ingredients in many medications. ²

c. 

Gas chromatography or gas mass spectroscopy can distinguish medications that may cause a false-positive toxicology screen. ³

TABLE 2-1

URINE TOXICOLOGY SCREEN ^∗

Agent	Time Detectable in Urine
Amphetamines	2–4 days; up to 15 days
Benzodiazepines	3 days (if short-term use); 4–6 weeks (if 1 year use)
Buprenorphine	3–4 days
Cannabinoids	2–7 days (occasional use); 21–30 days (chronic use)
Cocaine	12 hours (parent form); 12–72 hours (metabolites)
Codeine	2–6 days
Ethanol	2–4 hours; up to 24 hours
Heroin	2–4 days
Hydromorphone	2–4 days
Methadone	Up to 3 days
Methamphetamine	2–5 days (depends on urine pH)
Morphine	2–4 days (up to 14 days)
Phencyclidine (PCP)	2–8 days (occasional use); 30 days (regular use)

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The length of detection of drugs of abuse in urine varies. The above periods of detection should only be considered rough estimates and depend upon the individual's metabolism, physical condition, fluid intake, frequency, and quantity of ingestion. ⁴

∗ Recognize drugs not detected by routine toxicology screens.

C. 

Clinical Diagnostic Aids ( Table EC 2-A )

III

Toxidromes

( Table 2-2 ) 

TABLE 2-2

TOXIDROMES

Drug Class	Signs and Symptoms	Causative Agents
Anticholinergic: "Mad as a hatter, red as a beet, blind as a bat, hot as a hare, dry as a bone."	Delirium, psychosis, paranoia, dilated pupils, thirst, hyperthermia, ↑HR, urinary retention	Antihistamines, phenothiazines, scopolamine, tricyclic antidepressants
Cholinergic: Muscarinic	Salivation, lacrimation, urination,defecation, ↑HR emesis, bronchospasm	Organophosphates
Cholinergic: Nicotinic	Muscle fasciculations, paralysis, ↑HR, ↑BP	Tobacco, black widow venom, insecticides
Opiates	Sedation, constricted pupils, hypoventilation, ↓BP	Opioids
Sympathomimetics	Agitation, dilated pupils, ↑HR, ↓BP, moist skin	Amphetamines, cocaine, albuterol, caffeine, PCP
Sedative/hypnotic	Depressed mental status, normal pupils, ↓BP	Benzodiazepines, barbiturates,
Serotonergic	Confusion, flushing, ↑HR, shivering, hyperreflexia, muscle rigidity, clonus	SSRIs (alone or in combination with other meds including MAOIs, tramadol, and TCAs)

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TABLE EC2-A

Clinical Diagnostic Aids

Clinical Sign	Intoxicant
VITAL SIGNS
Hypothermia	Alcohol, antidepressants, barbiturates, carbamazepine, carbon monoxide, clonidine, ethanol, hypoglycemics, opioids, phenothiazines, sedative-hypnotics
Hyperpyrexia	Amphetamines, anticholinergics, antihistamines, atropinics, β-blockers, cocaine, iron, isoniazid, monoamine oxidase inhibitors (MAOIs), phencyclidine, phenothiazines, quinine, salicylates, sympathomimetics, selective serotonin reuptake inhibitors (SSRIs), theophylline, thyroxine, tricyclic antidepressants (TCAs)
Bradypnea	Acetone, alcohol, barbiturates, botulinum toxin, clonidine, ethanol, ibuprofen, opioids, nicotine, sedative-hypnotics
Tachypnea	Amphetamines, barbiturates, carbon monoxide, cyanide, ethylene glycol, isopropanol, methanol, salicylates Direct pulmonary insult: hydrocarbons, organophosphates, salicylates
Bradycardia	α-Agonists, alcohols, β-blockers, calcium channel blockers, central α 2 -agonist, clonidine, cyanide, digoxin, opioids, organophosphates, plants (lily of the valley, foxglove, oleander), sedative-hypnotics
Tachycardia	Alcohol, amphetamines, anticholinergics, antihistamines, atropine, cocaine, cyclic antidepressants, cyanide, iron, phencyclidine, salicylates, sympathomimetics, theophylline, TCAs, thyroxine
Hypotension	α-Agonists, angiotensin-converting enzyme (ACE) inhibitors, barbiturates, carbon monoxide, cyanide, iron, methemoglobinemia, opioids, phenothiazine, sedative-hypnotics, TCAs Profound hypotension: β-blockers, calcium channel blockers, clonidine, cyclic antidepressants, digoxin, imidazolines, nitrites, quinidine, propoxyphene, theophylline
Hypertension	Amphetamines, anticholinergics, antihistamines, atropinics, clonidine, cocaine, cyclic antidepressants (early after ingestion), diet pills, ephedrine, MAOIs, nicotine, over-the-counter cold remedies, phencyclidine, phenylpropanolamine, pressors, sympathomimetics, TCAs Delayed hypertension: Thyroxine
Hypoxia	Oxidizing agents
NEUROMUSCULAR
Nervous system instability	Insidious onset: Acetaminophen, benzocaine, opioids Abrupt onset: Lidocaine, monocyclic or tricyclic antidepressants, phenothiazines, theophylline Delayed onset: Atropine, diphenoxylate Transient instability: Hydrocarbons
Depression and excitation	Clonidine, imidazolines, phencyclidine
Ataxia	Alcohol, anticonvulsants, barbiturates, carbon monoxide, heavy metals, hydrocarbons, solvents, sedative-hypnotics
Chvostek/Trousseau signs	Ethylene glycol, hydrofluoric acid-induced hypocalcemia, phosphate-induced hypocalcemia from Fleet enema
Coma	Alcohol, anesthetics, anticholinergics (antihistamines, antidepressants, pheothiazines, atropinics, over-the-counter sleep preparations), anticonvulsants, baclofen, barbiturates, benzodiazepines, bromide, carbon monoxide, chloral hydrate, clonidine, cyanide, cyclic antidepressants, γ-hydroxybutyrate (GHB), hydrocarbons, hypoglycemics, inhalants, insulin, lithium, opioids, organophosphate insecticides, phenothiazines, salicylates, sedative-hypnotics, tetrahydrozoline, theophylline
Delirium, psychosis	Alcohol, anticholinergics (including cold remedies), cocaine, heavy metals, heroin, LSD, marijuana, mescaline, methaqualone, peyote, phencyclidine, phenothiazines, steroids, sympathomimetics
Miosis	Barbiturates, clonidine, ethanol, opioids, organophosphates, phencyclidine, phenothiazines, muscarinic mushrooms
Mydriasis	Amphetamines, antidepressants, antihistamines, atropinics, barbiturates (if comatose), botulism, cocaine, glutethimide, LSD, marijuana, methanol, phencyclidine
Nystagmus	Barbiturates, carbamazepine, diphenylhydantoin, ethanol, glutethimide, MAOIs, phencyclidine (both vertical and horizontal), sedative-hypnotics
Paralysis	Botulism, heavy metals, paralytic shellfish poisoning, plants (poison hemlock)
Seizures	Ammonium fluoride, amphetamines, anticholinergics, antidepressants, antihistamines, atropine, β-blockers, boric acid, bupropion, caffeine, camphor, carbamates, carbamazepine, carbon monoxide, chlorinated insecticides, cocaine, cyclic antidepressants, diethyltoluamide, ergotamine, ethanol, GHB, Gyromitra mushrooms, hydrocarbons, hypoglycemics, ibuprofen, imidazolines, isoniazid, lead, lidocaine, lindane, lithium, LSD, meperidine, nicotine, opioids, organophosphate insecticides, phencyclidine, phenothiazines, phenylpropanolamine, phenytoin physostigmine, plants (water hemlock), propoxyphene, salicylates, strychnine, theophylline
CARDIOVASCULAR
Hypoperfusion	Calcium channel blockers, iron
Wide QRS complex	TCAs
ELECTROLYTES
Anion gap metabolic acidosis	Acetaminophen, carbon monoxide, chronic toluene, cyanide, ethylene glycol, ibuprofen, iron, isoniazid, lactate, methanol, metformin, paraldehyde, phenformin, salicylates
Electrolyte disturbances	Diuretics, salicylates, theophylline
Hypoglycemia	Alcohol, β-blockers, hypoglycemics, insulin, salicylates
Serum osmolar gap	Acetone, ethanol, ethylene glycol, isopropyl alcohol, methanol, propylene glycol Calculated osmolarity = (2 × serum Na) + BUN/2.8 + glucose/18. Normal osmolarity is 290 mOsm/kg
SKIN
Asymptomatic cyanosis	Methemoglobinemia
Cyanosis unresponsive to oxygen	Aniline dyes, benzocaine, nitrites, nitrobenzene, phenazopyridine, phenacetin
Flushing	Alcohol, antihistamines, atropinics, boric acid, carbon monoxide, cyanide, disulfiram
Jaundice	Acetaminophen, carbon tetrachloride, heavy metals (iron, phosphorus, arsenic), naphthalene, phenothiazines, plants (mushrooms, fava beans)
ODORS
Acetone	Acetone, isopropyl alcohol, phenol, salicylates
Alcohol	Ethanol
Bitter almond	Cyanide
Garlic	Heavy metal (arsenic, phosphorus, thallium), organophosphates
Hydrocarbons	Hydrocarbons (gasoline, turpentine, etc.)
Oil of wintergreen	Salicylates
Pear	Chloral hydrate
Violets	Turpentine
RADIOLOGY
Small opacities on radiograph	Halogenated toxins, heavy metals, iron, lithium, densely packaged products

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IV

Ingestion and Antidotes

( TABLE 2-3 ) 

TABLE 2-3

COMMONLY INGESTED AGENTS ⁴

Ingested Agent	Signs and Symptoms	Antidote 4
Acetaminophen	See Section V
Amphetamine	See sympathomimetics toxidrome in Table 2-3	Supportive care (see above)
Anticholinergics 1	See anticholinergic toxidrome in Table 2-3	Physostigmine: See formulary for dosing
Anticholinesterase (insecticides, donepezil, mushrooms)	See cholinergic:muscarinic and cholinergic:nicotinic toxidrome in Table 2-3	Atropine: See formulary for dosing
Antihistamines 5	See anticholinergic toxidrome in Table 2-3 ; paradoxical CNS stimulation, dizziness, seizures	Supportive care (see above)
Benzodiazepines 67	Coma, dysarthria, ataxia, drowsiness, hallucinations, confusion, agitation, bradycardia, hypotension, respiratory depression	Flumazenil: See formulary for dosing
β-blockers 8910	Coma, seizures, altered mental status, hallucinations, bradycardia, congestive heart failure, hypotension, respiratory depression, bronchospasm, hypoglycemia	Glucagon: See formulary for dosing; seeinsulin/dextrose treatment in calcium channel blockers
Calcium channel blockers 910	Seizures, coma, dysarthria, lethargy, confusion, cardiac arrhythmia, hypotension, pulmonary edema, hyperglycemia, flushing	CaCl (10%): See formulary for dosing CaGluc (10%): See formulary for dosing Glucagon: See formulary for dosing Insulin/dextrose: 1 U/kg bolus → infuse at 0.1–1 U/kg/hr; give with D25% 0.25 g/kg bolus → 0.5 g/kg/hr infusion
Clonidine 10	Symptoms resemble an opioid toxidrome. CNS depression, coma, lethargy, hypothermia, miosis, bradycardia, profound hypotension, respiratory depression	See opioid antidote
Cocaine 11	See sympathomimetics toxidrome in Table 2-3	Supportive care (see above)
Ecstasy 11	Hallucinations, teeth grinding, hyperthermia, seizures	Supportive care (see above)
Ethanol 112	See sedative/hypnotic toxidrome in Table 2-3	Supportive care (see above)
Ethylene glycol/methanol 112	Similar to ethanol; additionally blurry or double vision, metabolic acidosis, abdominal pain	Fomepizole: See formulary for dosing. Alternatively, if not available, can use Ethanol (see formulary for dosing), but requires more monitoring than fomepizole.
Iron 1314	Vomiting, diarrhea, ↓BP, lethargy, renal failure	Deferoxamine: See formulary for dosing
Lead	See Section VI
NSAIDs	Nausea, vomiting, epigastric pain, headache, GI hemorrhage, renal failure	Supportive care (see above)
Opioids	See opioid toxidrome in Table 2-3	Naloxone: See formulary for dosing
Organophosphates	See cholinergic:muscarinic toxidrome inTable 2-3	If muscle fasciculations, respiratory depression, coma, use Pralidoxime: see formulary for dosing. Atropine: used for muscarinic effects (see anticholinesterase)
Salicylates 12	GI upset, tinnitus, tachypnea, hyperpyrexia, dizziness, lethargy, dysarthria, seizure, coma, cerebral edema	Supportive care (see above)
Serotonin syndrome	Seizures, muscle rigidity, myoclonus, hyperpyrexia, flushing, rhabdomyolysis	Cyproheptadine: See formulary for dosing; for agitation: Diazepam: See formulary for dosing
Sulfonylureas 12	Fatigue, dizziness, agitation, confusion, tachycardia, diaphoresis	Dextrose: 0.5–1 g/kg (2–4 mL/kg of D25W) After euglycemia achieved: Octreotide: 1–2 mcg/kg SQ Q6–12 hr if rebound hypoglycemia after dextrose
TCA 1516	Seizures, delirium, ventricular arrhythmias, hypotension	For wide QRS complex: NaHCO 3 : 1–2 mEq/kg IV; goal serum pH 7.45–7.55, For torsades: MgSulfate: 50 mg/kg IV over 5–15 min (max dose 2 g)
Warfarin	Bleeding	Phytonadione/Vitamin K 1 : See formulary for dosing

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A. 

In general, the following are guidelines of supportive care for the management of ingestions.

&lt1. 

For hypotension, patients often require aggressive fluid resuscitation or vasopressors.

&lt2. 

Treat hyperpyrexia with cooling measures.

&lt3. 

For ingestions that cause seizure, treat with benzodiazepines unless otherwise specified.

&lt4. 

Selective decontamination with activated charcoal.

&lt5. 

Hemodialysis may be indicated to remove a drug/toxin regardless of renal function or in cases of renal impairment.

B. 

Consult local poison control for further management at 1-800-222-1222. Consult Poisindex if available.

V

Acetaminophen Overdose ^417181920

Metabolites are hepatotoxic. Reactive intermediates can cause liver necrosis.

A. 

Four Phases of Intoxication

&lt1. 

Phase 1 (first 24 hr): nonspecific symptoms such as nausea, malaise, vomiting.

&lt2. 

Phase 2 (24 to 72 hr): above symptoms resolve, RUQ pain and hepatomegaly develop. Increase in liver function tests, bilirubin levels, and prothrombin time.

&lt3. 

Phase 3 (72 to 96 hr): return of nonspecific symptoms as well as evidence of liver failure (e.g., jaundice, hypoglycemia, coagulopathy).

&lt4. 

Phase 4 (4 days to 2 weeks): recovery or death.

B. 

Treatment Criteria:

&lt1. 

Serum acetaminophen concentration above the possible toxicity line on the Rumack-Matthew nomogram ( Fig. 2-1 ). 

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FIGURE 2-1

Semilogarithmic plot of plasma acetaminophen levels versus time. This nomogram is valid for use after acute ingestions of acetaminophen. The need for treatment cannot be extrapolated based on a level before 4 hours.

(Based on Pediatrics 55:871, 1975 and Micromedex.)

&lt2. 

History of ingesting more than 200 mg/kg or 10 g (whichever is less) and serum concentration not available or time of ingestion not known.

C. 

Antidotes: N-Acetylcysteine

&lt1. 

PO: 140 mg/kg loading dose followed by 70 mg/kg Q4 hr for a total of 72 hours.

&lt2. 

IV: 150 mg/kg N-acetylcysteine IV over 60 minutes followed by 12.5 mg/kg/hr x 4 hours followed by 6.25 mg/kg/hr x 16 hours for a total of 21 hours of infusion. Some patients may require more than 21 hours of N-acetylcysteine.

&lt3. 

Liver failure: treat patients in liver failure with N-acetylcysteine IV, same dose as above. Continue 6.25 mg/kg/hr infusion until resolution of encephalopathy, decreasing aminotransferases and improvement in coagulopathy

VI

Lead Poisonings ²¹²²²³

A. 

Etiologies: paint, dust, soil, drinking water, cosmetics, cookware, toys, and caregivers with occupations and/or hobbies utilizing lead-containing materials or substances. ∗

∗ Children aged 1 to 5 years are at greatest risk of lead poisoning.

B. 

Definition: Centers for Disease Control and Prevention (CDC) defines an elevated blood lead level (BLL) as ≥5 mcg/dL. 21

C. 

Overview of Symptoms by BLL:

&lt1. 

BLL 40 mcg/dL: irritability, vomiting, abdominal pain, constipation, and anorexia.

&lt2. 

BLL 70 mcg/dL: lethargy, seizure, and coma. 

NOTE: Children may be asymptomatic with lead levels 100 mcg/dL.

C. 

Management ( Tables 2-4, 2-5, and 2-6 ): 

TABLE 2-4

MANAGEMENT OF LEAD POISONING ²¹

Blood Lead Levels (BLL)	Recommended Guidelines
≥ 5 and <10 mcg/dL	&lt1.  Provide education about reducing environmental lead exposure and reducing dietary lead absorption. ∗ &lt2.  Perform environmental assessment in homes built before 1978. &lt3.  Follow repeat blood lead testing guidelines (see Table 2-5 ).
≥ 10 and ≤45 mcg/dL	&lt1.  As above for BLL ≥ 5 and <10 &lt2.  Environmental investigation and lead hazard reduction &lt3.  Complete history and exam &lt4.  Iron level, complete blood cell count (CBC), abdominal radiography (if ingestion is suspected) with bowel decontamination if indicated &lt5.  Neurodevelopmental monitoring
BLL ≥45 and ≤69 mcg/dL	&lt1.  As above for BLL ≤45 mcg/dL &lt2.  Check free erythrocyte protoporphyrin. &lt3.  Administer chelation therapy (See below).
BLL ≥70 mcg/dL	&lt1.  As above for BLL ≥45 mcg/dL &lt2.  Hospitalize and commence chelation therapy.

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∗ Iron, calcium, and vitamin C help minimize absorption of lead.

TABLE 2-5

REPEAT BLOOD LEAD TESTING GUIDELINES ²¹

If Screening BLL is:	Time Frame of Confirmation of Screening BLL	Follow-Up Testing (After Confirmatory Testing)	Later Follow-Up Testing After BLL Declining
≥ 5–9 mcg/dL	1–3 months	3 months	6–9 months
10–19 mcg/dL	1 week–1 month ∗	1–3 months	3–6 months
20–24 mcg/dL	1 week–1 month ∗	1–3 months	1–3 months
25–44 mcg/dL	1 week–1 month ∗	2 weeks–1 month	1 month
45–59 mcg/dL	48 weeks	As soon as possible
60–69 mcg/dL	24 hours
70 mcg/dL	Urgently

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∗ The higher the blood lead level (BLL) on the screening test, the more urgent the need for confirmatory testing.

Chelation Therapy

1. 

Routine indication: BLL ≥ 46 mcg/dL

Overview of antidotes:

Succimer: 10 mg/kg or 350 mg/m ² PO Q8 hr x 5 days -- Q12 hr x 14 days

Edetate (EDTA) calcium disodium: 1000 mg/m ² /24 hr IV infusion as an 8-24 hr infusion OR intermittent dosing divided Q12 hr x 5 days. May repeat course as needed after 2-4 days of no EDTA. 

∗Warning: Do not mistake edetate disodium for edetate calcium disodium. Edetate calcium disodium is used for the treatment of lead poisoning.

D-penicillamine: 25-35 mg/kg/day PO in divided doses. Start at 25% of this dose and increase to full dose over 2-3 weeks. Do not give D-penicillamine to patients with a penicillin allergy.

Non-routine indications: patient with encephalopathy

Give Dimercaprol (BAL): 75 mg/m ² IM Q4 hr x 5 days; immediately after second dose of BAL give EDTA 1500 mg/m ² /day IV as a continuous infusion or 2-4 divided doses x 5 days