1. Toxicology: A Practical Approach
Lou Hampers, MD
Pediatric Emergency Medicine
The Children’s Hospital
Denver, CO
Thanks to:
Carl Baum MD
Toxikon
Cook County Hosp.
Chicago, IL

2. Toxicology: the ABCs Airway Breathing Circulation Diagnosis
Decontamination
Enhanced removal

3. Diagnosis What? How much? When? Containers PoisIndex and Pill ID
Avoid PDR
How much?
Assume largest amount
When?

4. Diagnosis Pupils Constricted sympatholytics cholinergics barbiturates
opiates
PCP
ethanol / sedative-hypnotics
other: heatstroke; pontine or subarachnoid
hemorrhage

5. Diagnosis
Pupils
Dilated
sympathomimetics
anticholinergics

6. Toxidromes: anticholinergic
Diagnosis
Toxidromes: anticholinergic
Mad as a hatter
Red as a beet
Hot as a hare
Blind as a bat
Dry as a bone

7. Toxidromes: cholinergic
Diagnosis
Toxidromes: cholinergic
muscarinic
Salivation
Lacrimation
Urination
Defecation
GI motility
nicotinic
tachycardia, hypertension
fasciculations, paralysis

8. Diagnosis Odors arsenic, organophosphates, thallium: garlic
chloral hydrate, paraldehyde: pear
chloroform, isopropyl alcohol: acetone
cyanide (only 50% can detect): almond
methylsalicylate: oil of wintergreen
naphthalene, paradichlorbenzene: mothball
water hemlock: carrot

9. Diagnosis Elevated anion gap Are organic acids present?
gap = Na - Cl - CO2
(normal = meq/L)

10. Diagnosis Elevated anion gap Alcohol (but not isopropyl!) Tolulene
Methanol
Uremia
Diabetes mellitus
Paraldehyde
Iron, Isoniazid
Lactic acidosis
Ethylene glycol
Salicylates, Strychnine

11. Diagnosis Elevated osmolal gap
What is the difference between what is measured and what is calculated?
2 (Na) + glucose/18 + BUN/2.8 [calculated osm]
+ Methanol/2.8
+ Ethanol/4.3
+ Ethylene Glycol/5.0
+ Isopropanol/5.9

12. Diagnosis “Tox screen” Plasma/Serum Urine
good for levels of selected substances
Acetaminophen, ASA, CO, CBZ, Dig, DPH, EtOH, Fe, Li, Phenobarb, Theo
avoid comprehensive (send-out)
Urine
good for drugs of abuse screen (in-house)
amphetamines, barbs, benzodiazepines, cocaine, cannabinoids, opiates, pcp

13. Diagnosis Abdominal xrays “Bet-a-chip” Barium Enteric coated tablets
Tricyclics
Antihistamines
Chloral hydrate, Cocaine, Condoms
Heavy metals
Iodides
Potassium, Phenothiazines

14. Decontamination Universal Antidote Burned toast Milk of magnesia
Strong tea

15. Decontamination Emesis (ipecac) Indications (not many!)
home-management of Fe, Li, K
Contra-indications
obtunded/comatose/convulsing
likelihood of rapid progression
TCA, camphor, cocaine, INH
corrosives
petroleum distillates

16. Decontamination Gastric lavage Indications Contra-indications
removal of ingested material
administration of charcoal/cathartics
Contra-indications
obtunded/comatose/convulsing
corrosives (?)

17. Decontamination Activated charcoal Indications Contra-indications
numerous poisons, except some which are not well adsorbed:
alcohols, alkalis, acids
CN, Fe, K, Li, Pb
Contra-indications
ileus/obstruction
corrosives (endoscopy)

18. Decontamination Repeat-dose charcoal Cathartics Whole Bowel Irrigation
some anti-convulsants
salicylates
theophylline
Cathartics
magnesium citrate (4 ml/kg)
use with caution in children < 2 years
Whole Bowel Irrigation

19. Enhanced Elimination Methods Urinary Hemodialysis Hemoperfusion
Peritoneal dialysis
Multi-dose charcoal
Whole bowel irrigation

20. Enhanced Elimination Specific “Antidotes”
Acetaminophen N-acetylcysteine
COHb oxygen, HBO
Digoxin Fab
Ethylene Glycol EtOH, dialysis
Iron deferoxamine
Lithium fluids, dialysis
Methanol EtOH, dialysis
Salicylate alkalinization, dialysis
Theophylline repeat AC, hemoperfusion

21. Acetaminophen History When? Acute or chronic? How much? Physical
dosage? 80, 160, 325, 500, 650?
toxic: >150 mg/kg
Physical
Nausea, emesis

22. Acetaminophen Acetaminophen NAPQI is hepatotoxic
Sulfate, Glucuronide (major)
NAPQI (minor)
NAPQI is hepatotoxic
Glutathione detoxifies NAPQI

23. Acetaminophen Laboratory Acetaminophen (draw after 4 h)
AST, ALT, PT may increase, but after 24 h
Bili, Ammonia may also increase

24. Rumack-Matthew Nomogram
Acetaminophen
Rumack-Matthew Nomogram
200
150
mcg/ml
4 h

25. Acetaminophen Treatment Glutathione substitute Precursor for sulfate
Antioxidant

26. N-acetylcysteine (NAC, Mucomyst®)
Acetaminophen
N-acetylcysteine (NAC, Mucomyst®)
Dilute to 5%, cover, on the rocks!
Load: 140 mg/kg po
Maint: 70 mg/kg po q 4 h x 17 doses
Premedicate with antiemetics prn
Follow LFTs, PT

27. Methanol, Ethylene Glycol
Alcohols and Glycols
Methanol, Ethylene Glycol
alcohol dehydrogenase
Organic Acids

28. Alcohols and Glycols History Lethargy, ataxia Physical Hypothermia
Respiratory depression
CNS depression (“intoxication”)

29. Alcohols and Glycols Laboratory Check d-stick Check anion and osm gap
Send out methanol or ethylene glycol level

30. Alcohols and Glycols Treatment Provide supportive care
Block formation of toxic metabolites
Dialysis

31. Alcohols and Glycols Treatment Ethanol block Dialysis
level (osm gap) > 20 mg/dl
Dialysis
level (osm gap) > 50 mg/dl

32. Alcohols and Glycols
4-methylpyrazole (fomepizole, Antizol™)

33. Hydrocarbons Aromatics: systemic toxicity
benzene, toluene, xylene
Aliphatics: aspiration hazard
gasoline, kerosene, lamp oil
Hx or PE significant for cough, dyspnea, fever, cyanosis, rales

34. Hydrocarbons Aromatics Aliphatics remove via NG if > 1 ml/kg
do not remove unless > 5 ml/kg
clinical/radiographic signs of pneumonitis may be delayed
antibiotics, steroids not helpful

35. Iron How much? Vitamins + Fe rarely a problem
Prenatal iron can be lethal
Ipecac: home-management of
> 20 mg/kg

36. Iron History Within 2 h: GI symptoms
6-24 h: fever, metabolic acidosis, hepatic impairment, seizures, shock and coma

37. Iron Laboratory Serum Fe level at 2 h CBC, electrolytes if symptomatic
6 h to r/o delayed absorption
CBC, electrolytes if symptomatic
Consider KUB to r/o radio-opaque tablets or bezoar

38. Iron Treatment Consider whole bowel irrigation
25 ml/kg/h
Deferoxamine if serum Fe > 500 mg/dl
15 mg/kg/h

39. Salicylates History Physical Various forms of salicylates Hyperthermia
Deep, rapid respirations
Emesis, dehydration
Coma, seizures

40. Salicylates Laboratory Initial respiratory alkalosis
Later metabolic acidosis
Platelet, coag dysfunction
Hyper- or hypoglycemia

41. Salicylates Laboratory Peak serum levels @ 2 to 6 hours
Symptomatic > 50 mg/dl
Potentially fatal > 100 mg/dl
Nomogram not helpful

42. Salicylates Treatment Lower temperature (sponging)
Correct fluid losses, hypoglycemia
Correct prolonged PT with Vitamin K
Urine alkalinization (> pH 7.5)
shortens half-life via ion trapping
may need potassium

43. Salicylates Laboratory Consider multi-dose charcoal
Consider dialysis for levels > 100 mg/dl

44. Tricyclic Antidepressants
Mechanisms
Therapeutic
anticholinergic effects
inhibition of neurotransmitter reuptake
stabilization of membranes

45. Tricyclic Antidepressants
Mechanisms
Overdose
therapeutic mechanisms are seen
inhibition of fast Na channels
membrane-depressant effects
cardiac toxicity

46. Tricyclic Antidepressants
Physical
Abrupt decompensation
Tachycardia, dysrhythmias
Sedation, seizures

47. Tricyclic Antidepressants
Laboratory
ECG may reveal QRS > 100 msec
predicts toxicity
other ECG abnormalities seen
TCA levels not clinically useful

48. Tricyclic Antidepressants
Treatment
Anticipate dysrhythmias, respiratory failure and ARDS
Ipecac: NO!
Give charcoal (via NG prn)

49. Tricyclic Antidepressants
Treatment
If QRS prolongation or refractory hypotension:
serum alkalinization
(pH )

50. Tricyclic Antidepressants
Serum Alkalinization
bolus Na bicarb 1-2 mEq/kg
increase extracellular Na may reverse membrane depression
alkaline pH may stabilize ion channels
hyperventilation not as effective

51. Fun with Mnemonics Hyperthermia NASA NMS, Nicotine Antihistamines
Salicylates, Sympathomimet.
Anticholinergics, Antidepressants
Hypothermia
COOLS CO
Opiates
Oral hypogly. (insulin)
Liquor
Sed-hypnotics

52. Fun with Mnemonics Tachycardia FAST Free base
Anticholinergics, Amphetamines
Sympathomim., Solvent
Theophylline
Bradycardia
PACED
Propranolol
Anticholin’ase
Clonidine, CCBs
Ethanol
Digoxin

53. Fun with Mnemonics Rapid Respirations PANT PCP, Paraquat, Pneumonitis
ASA
Noncardio. PE
Toxin-induced metabolic acid.
Slow Respirations
SLOW
Sed-hypnotics
Liquor
Opiates
Weed (marijuana)

54. Fun with Mnemonics Hypertension CT SCAN Cocaine Thyroid, Theoph.
Sympathomim.
Caffeine
Anticholinergics
Nicotine
Hypotension
CRASH
Clonidine, CCBs
Reserpine
Antidepressants
Sed-hypnotics
Heroin

55. Fun with Mnemonics Seizures OTIS CAMPBELL
Organophosphates
Tricyclics
INH, Insulin
Sympathomim.
Camphor, Cocaine
Amphetamines
Methylxanthines
PCP
Benzo withdrawl
Ethanol withdrawl
Lithium, Lidocaine
Lead, Lindane

56. Non-toxic Ingestions Antibiotics Baby oil Bleach Cigarettes Cologne
Contraceptive pills
Cosmetics
Detergent
Glue
Hydrogen peroxide
Laxatives
Paint
Rat poison
Shampoo
Thermometers
Vitamins