Pediatric Toxicology

1. Pediatric Toxicology Jay Fisher MD Pediatric Emergency Services University Medical Center

2. Epidemiology • 2.4 million events reported to U.S. poison centers annually • ~50% are in children < 6 years. • Less than 50 deaths annually. • 10 Fold decrease in deaths since 1950

3. Reason For Decrease = Prevention • Packaging legislation – child resistant closures • Safer medications (tetracyclic > tricyclic) • Consumer Product Safety measures • Poison Centers – 1-800-222-1222 • Anticipatory Guidance

4. Clinical Approach - History • Details are extremely important and will strongly impact management. • Identify the potential poisons. • Create an accurate time line. • How long was the child unattended? • Medications in the home, visitors?

5. Symptoms and Physical Exam – Toxidrome? • Vomiting, diarrhea, lacrimation? • Loss of conciousness, seizure, rash? • Vital signs • Mental status

6. Anti-cholinergic Poisoning • Red as a beet – Diffuse erythema • Dry as a bone – Dry mucous membranes • Mad as a hatter – Confusion, psychosis, seizures • Hot as Hades – Temperature elevation, tachycardia, hypertension. • Blind as a bat - Mydriasis, sluggish to light

7. Cholinergic Excess - SLUDGE • Salivation • Lacrimation • Urination • Defecation • Gastric Cramping • Emesis

8. Sympathomimetics • Agitation, confusion, combative, convulsion • Tachycardia, Hypertension, Elevated temperature • Mydriasis, Reactive to Light • Diaphoresis

9. Opiates • Euphoria, somnolence, unresponsive • Pinpoint pupils • Respiratory depression • Bradycardia, hypotension • Decreased body temperature

10. Serotonin Syndrome • Typically occurs with patients on multiple agents, particularly SSRIs • Case reports of kids with SS after a single dose of some SSRIs.

11. Serotonin Syndrome • Autonomic instability, fever • Confusion, seizures, agitation • Increased tone in the lower extremities • Myoclonus • Reminiscent of Neuroleptic Malignant Syndrome

12. NMS vs SS • Higher fever • Develops slower (days vs hours) • Rigidity and bradykinesis as opposed to myoclonus and hyperkinesis • More extra-pyramidal symptoms – jaw stiffness, athetosis

13. Clinical Intervention:Gastrointestinal Decontamination • Ipecac – Never • Gastric Lavage – Rarely • Activated Charcoal – Infrequent • Whole Bowel Irrigation – Rarely • Laparotomy – Very Rarely

14. Activate Charcoal A legitimate controversy

15. Activated Charcoal – An adsorbant. • Burn wood, oxidize it at high temperatures with steam or CO2. • Creates an internal trellis of pores with a surface area of 2 m2 per gram! • Dose = 1 g/ kg. • Sorbitol additive is not necessary.

16. Adult Volunteer Studies – Reduction of Absorbed Dose

17. Am Ass. of Clin Tox – Position Paper -2005 • “There is no evidence… charcoal improves clinical outcomes.” • “Based on volunteer studies”…. Charcoal may be considered ‘in high risk patients presenting within one hour of ingestion’.

18. Fleisher & Ludwig - 2005 • Continues to recommend activated charcoal routinely in poisonings in which the patient presents to the ED and the toxin is still ‘believed to be in the stomach’. • Still advocates multi-dose activated charcoal (GI dialysis) for certain poisons- theophylline, phenobarb, carbamazepine

19. Activated Charcoal – No Utility • Alcohols • Iron • Lithium • Caustics

20. Activated Charcoal - Contraindications • Patient with an unprotected airway. • Caustics – Vomiting may worsen esophageal injury • Hydrocarbons – Vomiting increases risk of aspiration pneumonitis.

21. Activated Charcoal – Why not? • Labor intensive. • Can often require naso-gastric tube placement to give a full dose. • If patient decompensates, refluxing charcoal can be a big problem. • Several case reports of aspiration pneumonia leading to death in children.

22. Side Effects

23. Poisonings – What kills children? • Hydrocarbons • Cardiovascular drugs • Narcotics • Tri-cyclic antidepressants • Industrial Chemicals • Envenomations • Anti-convulsants

24. When a Pill can Kill • Calcium Channel Blockers • Clonidine/ Other Imidazoles • TCA’s • Theophylline • Sulfonylureas • Diphenoxylate (Lomotil) • Camphor and Methylsalicylate

25. Antidotes • Desferoxamine • Sodium Bicarbonate • Calcium Chloride/ Gluconate • Methylene Blue • Octreatide • Pralidoxime • Vitamin K

26. Cases In Our Own Backyard

27. 18 mos old female brought by EMS with AMS • No history of trauma • No infectious prodrome • No history of toxic exposures

28. Physical Exam • Temperature = 99 • HR = 240 • RR = 26 • BP = 121/76 • Alternating horizontal & vertical nystagmus • Extensor posturing

29. PE - continued • Abdomen distended, soft. • Skin- upper face and trunk bright red • Pupils 5 mm and reactive

30. Case Progression • Child requires benzodiapines, intubation, mechanical ventilation and bicarb. • Blood serology returns positive for amitriptyline, which a visiting grandparent is taking. • No further arrythmias develop. • Patients discharged without sequelae several days later.

31. 2.5 yo female with lethargy • Sudden onset of decreased responsiveness describe. • No toxic exposures noted. • No vomiting, no rash. • No past medical history

32. Acute AMS

35. 15 yo female with Celexa overdose • Patient is on Celexa chronically for depression. • Patient has a history of overdose in the past. • Ingestion occurred two hours ago. • Mother is forcefully demanding immediate intervention!

36. Physical Exam • Nursing assessment – ‘Patient will not cooperate with assessment.’ • Vitals – T = 96.9/ HR = 144/ RR = 23/ BP = 167/71/ sat = 100% on RA • Eyes closed but would open to command. • Answers questions appropriately. • Hyperventilating intermittently. • Intermittent myoclonus.

37. Case Progression • During discussion of the risks and benefits of gastric emptying with the mother, the patient starts seizing, loses her airway, and requires intubation. • The patient’s seizures are treated with lorazepam. • Patient is transferred to Monte Vista several days later without sequelae.

38. 15 yo arguing with boyfriend • Ingested an ounce of ‘rubbing alcohol’ to get a buzz after arguing with boyfriend. • Vomited shortly after ingestion. • Known to be an abuser of ethanol and marijuana. • Denies suicidal intent or ideation.

39. Physical Exam • Awake, alert, cooperative. • Vitals: T = 98/ HR = 102/ RR = 18/ BP = 120/72 • Negative remainder of physical exam.

40. Case Progression • Child is discharged to follow-up with PMD in a couple of days. • Vomiting and abdominal pain worsens over the next six hours. • Patient returns to ED and admits to taking 30 acetaminophen tablets with the rubbing alcohol 8 hours ago. • 8 hour level = 140 mcg/ml

41. Acetaminophen Overdose • Most common agent ingested by teenagers during suicide. • Overdose very well tolerated by young children. • Over 150 mg/kg in a child, 10 to 15 grams in an adult can cause toxicity. • N-Acetyl Cysteine eliminates toxicity if given within 8 hours of ingestion, reduces toxicity up to 16 hours after ingestion.

42. APAP and Mucomyst • APAP metabolized by three separate pathways. • P450 pathway creates a toxic intermediate which usually is bound to glutathione and rendered harmless. • With glutathione depleted, toxic intermediate induces hepatitis. • NAC repletes glutathione