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PEDIATRIC TOXICOLOGY

PEDIATRIC TOXICOLOGY

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PEDIATRIC TOXICOLOGY

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  1. PEDIATRIC TOXICOLOGY Nga B. Pham, M.D.

  2. Epidemiology • 64 Poison Centers serving 295 million people • 2.4 million exposures last year • 39% are children younger than 3 years • 52% in children younger than 6 years • 106 deaths in age <19 for 2003 2003 Annual report of the American Association of Poison Control Centers Toxic Exporure Surveillance System – Watson et. al

  3. Epidemiology • Most commonly fatal classes of poisoning • Analgesics (375) • 62 Tylenol only, 52 Tylenol + 1 other, 100 Tylenol combination products (Lortab, etc.) • 23 ASA – more than half did not have ASA levels >100mg/dl – early and more aggressive dialysis recommended • Street drugs (124) • Antidepressants (112) • Amitriptyline

  4. Epidemiology • Most common Pediatric Exposure • Cosmetics and personal care products (13%) • Cleaning substances (10%) • Analgesics (7.8%) • Foreign Bodies (7.4%) • Topicals (7.4%) • Cold and Cough Preparations (5.5%) • Plants (4.6%) • Pesticides (4.1%)

  5. Epidemiology • Unintentional (1-2 years) • Exploratory • Boys > girls • Unable to discriminate safe from unsafe liquid • Intentional (adolescent) • Purposeful • Girls > boys

  6. Epidemiology • Around meal time • Grandparents home • Kerosene or gasoline in a soda bottle • Older sibling can pharmaceutically treat younger sibling

  7. Evaluation of Suspected Poisoning • ABC’s and routine ICU management • Establishing the diagnosis • Must consider poisoning, especially in “at risk” age groups • Less than 6 year old with acute decompensation (AMS, arrhythmias, hypotension, metabolic acidosis, etc.)

  8. Evaluation • History of poisoning • Physical Examination • Laboratory studies • Gastrointestinal decontamination

  9. History • What? • When? • How much? • Reliability…

  10. What? • Medication • Illicit drug • Hazardous chemical

  11. What forms? • Pill • Solid • Liquid • Gaseous

  12. What route? • Ingestion • Inhalation • Topical • Intravenous

  13. When? • Elapsed time

  14. How much? • Estimate amount • Concentration

  15. PICU Admission • Tricyclic antidepressants (TCA) • Anticonvulsants • Digoxin • Opiates • Hydrocarbon-based household products

  16. Toxic Exposure - Death • Analgesics • Sedative-hypnotics • Alcohols • Gases & fumes • Cleaning substances

  17. Toxidromes • Anticholinergics • Atropine, scopolamine, TCA’s, phenothiazines, antihistamines, mushrooms, jimson weed • “Hot as a hare, dry as a bone, red as a beet, mad as a hatter” • Neuro: agitation, hallucinations, coma, extrapyramidal movements, mydriasis, hyperthermia • CV: tachycardia, hypotension, hypertension, arrhythmia • GI/GU: decreased bowel sounds, urinary retention

  18. Toxidromes • Cholinergics • Organophosphates and carbamates

  19. Muscarinic Effects of Organophosphate Poisoning • S alivation *D iaphoresis/diarrhea • L acrimation *U rination • U rination *M iosis • D efecation *B radycardia/bronchospasm • G I secrestion/upset *E mesis • E mesis *L acrimation excess *S alivation excess

  20. Nicotinic Effects of Organophosphate Poisoning • Muscle fasciculation • Cramping • Weakness (extreme is diaphragmatic failure) • Autonomic nicotinic effects include hypertension, tachycardia, pupillary dilation, and pallor

  21. CNS Effects ofOrganophosphate Poisoning • Anxiety • Restlessness • Confusion • Ataxia • Seizures • Insomnia • Dysarthria • Tremors • Coma

  22. Toxidromes • Opiates: • Morphine, Methadone, Dextromethorphan

  23. Toxidromes • Opiates • Morphine, methadone, dextromethorphan • Resp: decreased respiratory rate, pulmonary edema • CV: hypotension, bradycardia • Neuro: miosis, AMS, coma, hypothermia, seizures

  24. Toxidromes • Sedatives/hypnotics • Benzodiazepines, barbiturates • Resp: slow respirations • CV: tachycardia, hypotension • Neuro: AMS, coma, seizures, hypothermia

  25. Toxidromes • Tricyclic antidepressants • Amitryptiline, nortryptiline, etc. • See anticholinergic effects • CV: arrhythmias, hypotension • Neuro: coma, seizures

  26. Toxidromes • Salicylates • ASA, oil of wintergreen • Resp: tachypnea

  27. Laboratory Tests Suggestive ofPoisoning • Elevated osmolar gap (>10) • Serum osm = (Na x 2) + BUN/2.8 + glucose/18 • Volatile alcohols, mannitol • Elevated anion gap (>12) • MUDPILES • Low anion gap • Lithium, iodine, bromine, fluoride • Hyperkalemia • Postassium, lithium, digoxin, fluoride • Hypokalemia • Theophylline, toluene

  28. Laboratory Tests Suggestive ofPoisoning • Hyperglycemia • ASA, theophylline, caffeine, iron • Hypocalcemia • Ethylene glycol, ASA • UA • Glowing urine – ethylene glycol • Calcium oxalate crystals – ethylene glycol

  29. Laboratory Testing • What is in a “urine drug screen”? • Amphetamines, Barbiturates, Cocaine, Benzodiazepine, Opiates, THC, PCP • What is in a “serum drug screen”? • Acetaminophen, ETOH, Salicylate, TCA • What is in a “comprehensive drug screen”? • Barbiturates, Salicylates, Cannabinoids, PCP, TCA, Sedatives, Benzodiazepines, Stimulants, Opium alkaloid, Synthetic Narcotics, Tranquilizers, Cocaine

  30. Laboratory Testing • Grady unfortunately doesn’t do HPLC anymore • Options for more “comprehensive” screen • Quest lab – if needed in 24 hours or less • ARUP – 2-4 days turn around • SERUM: Acetaminophen, alcohols, barbiturates, benzodiazepines, carbamazepine, carisoprodol, disopyramide, meprobamate, phenytoin, primidone, salicylate, theophylline, tricyclic and other antidepressants • URINE: acetaminophen, alcohols, barbiturates, benzodiazepines, carbamazepines, carisoprodol, chlorpheniramine, cocaine & metabolites, diphenhydramine,ethchlorvynol, ibuprefen, lidocaine, meprobamate, narcotics & synthetics, phencyclidine, phenothiazines, phenytoin, primidone & metabolites, pyrilamine, salicylate, sympathomimetic amines, theophylline, tricyclic and other antidepressants, trimethoprim

  31. Laboratory Testing • Additional testing is helpful if you have a specific substance that you suspect • Usually less helpful as a “fishing expedition” and won’t affect management • Am J Emerg Med. 1999 May:17(3):221-4. Belson MG, Simon HK • Evaluate the clinical utility and cost-effectiveness of the limited component vs the HPLC component of comprehensive toxicologic screens in children • Retrospective from HSCH ED Jan 1994-July 1995 • The comprehensive test included a broad-spectrum HPLC component as well as a limited component that examined serum for ethanol, aspirin, and acetaminophen and urine for benzodiazepines, barbiturates, amphetamines, cocaine, phencyclidien, and opiates • Comprehensive toxicology screens were performed in 463 cases during the study period; 234 (51%0 were positive for exogenous toxin

  32. Laboratory Testing • In 227 of 234 positive screens (97%), toxins were either suspected by history and/or physical, were present on the limited portion of the toxicology screens, or were clinically insignificant • The remaining 7 of the 234 positive screens (3%) were clinically significant and detected solely by the broad-spectrum HPLC portion of the comprehensive screen • However, in none of these 7 cases was patient management clinically altered as a result of the positive screen • The total additional cost of the HPLC component was $16,205 ($35x464), an average distributive charge of $2,315 per patient in whom the HPLC portion provided additional clinical information ($16,205/7) • Although adding significant charges to the evaluation of suspected toxic exposures in children, the HPLC component of the comprehensive drug screen was of no additional clinical benefit compared with its limited component alone

  33. Urine Drug Screens • THC 1-3 weeks* • Cocaine 2-4 days • Amphetamine 2 days • Barbiturates 1-2 days • Opiates 1-2 days • PCP 5-7 days • LSD 1-2 days • Steroids 3 days or longer * Longer if prolonged exposure

  34. Antidotes

  35. Antidotes

  36. Antidotes

  37. Antidotes

  38. Antidotes

  39. Antidotes

  40. Antidotes

  41. Antidotes

  42. Antidotes

  43. Antidotes

  44. Antidotes

  45. Antidotes

  46. Antidotes

  47. Antidotes

  48. Elimination of Poisons • Surface decontamination • Reduce any additional absorption • Ipecac • Not routinely recommended anymore • Possible useful in an observed, in hospital poisoning • Gastric Lavage • Most effective 1-2 hours after ingestion • Can be effective later in drugs that delay gastric emptying

  49. Elimination of Poisons • Activated charcoal • Adsorbs many drugs, thus decreasing systemic absorption • Doesn’t work well for lithium, iron, hydorcarbons, alcohols, solvents, acid/alkali ingestions • Role of charcoal in gastrointestinaldialysis • Cathartics • Not generally used • Some charcoal has sorbitol in it • Whole bowel irrigation • Golytely infusions • Initially done with success in iron ingestions • Used mostly for drugs that charcoal doesn’t work well with

  50. Elimination of Poisons • Diuresis +/- alteration of urine pH • Obviously, only useful for renally excreted drugs • Altering pH example • ASA – pkA3 • At a pH of 3, there is a 1:1 ratio of ionized/unionized • At a pH of 7.4, the ratio is 25,000:1 • Ionized form can’t cross cell membranes – so when you dump ASA into the tubule, if the pH is 4.5 you would have about 5,00:1 ratio, if you increase urine pH to 8.0, then essentially all of it is in the ionized form, and can’t get reabsorbed