Toxicology: Pediatrics and Approach to Poisoned Patient Flashcards
Evaluation of a Poisoned Child
Child presents with altered level of consciousness, metabolic disturbances, neurological dysfunction, cardiac/pulmonary distress?
Include toxic exposure as part of differential
Pediatrics Supportive Care Guidelines
Pediatric Advanced Life Support (PALS) Guidelines
Early airway stabilization
Early antidote administration (if indicated):
Organophosphates (insecticides or pesticides) —> Atropine
Iron —> Deferoxamine
Digoxin —> Digoxin antibody fragments (Fab)
Benzodiazepines —> Flumazenil
Lead —> Edetate Calcium Disodium (EDTA)
Methemoglobinemia —> Methylene Blue
Heparin —> Protamine
TCAs or Salicylates —> Sodium Bicarbonate
Warfarin —> Vitamin K
Pediatrics - Gastric Decontamination
Lack of evidence of efficacy limits use and discourages some methods
Syrup of ipecac - NOT recommended
Gastric Lavage - NOT recommended. Lack of efficacy data and relatively high complication rate
Activated Charcoal: Use within 1 hour at 0.5 to 1 g/kg. Optimal ratio 10:1 AC:drug. Vomiting most common ADE
Multiple dose activated charcoal (MDAC): >2 sequential dose administrations to prevent prolonged absorption or enterohepatic recirculation. MDAC enhances gastric dialysis of certain drugs. Loading dose of 1 g/kg followed by 0.5 g/kg every 4-6h for up to 24h
Whole Bowel Irrigation (WBI) - polyethylene glycol and electrolyte solution
Considered in patients who ingested: SR, EC, or iron (or other metals)
Can be given PO, but via NG tube is easier with kids
0.5 L/hr (smaller children) up to 1.2-2L/hr (older children and adolescents) for 4-6 hours
GoLYTELY, NuLYTELY, CoLyte
Do NOT use Miralax —> No electrolytes = electrolyte imbalances
Pediatrics - Acetaminophen
Toxic ingestion>200 mg/kg (oral) or >60 mg/kg (IV) in children
GI Decontamination: Activated Charcoal within 1 hour
Antidote: n-acetylcysteine (NAC). AEs: N/V/D, anaphylactoid rxns (rare)
Oral NAC: 140 mg/kg x1 then 70 mg/kg q4h x17 doses
IV NAC: (more often used in younger patients) 150 mg/kg infused over 1 hour, 50 mg/kg infused over 4 hours, 100 mg/kg infused over 16 hours
To avoid hyponatremia in children, product should be diluted to a concentration of 40 mg/mL
Pediatrics - Ethylene Glycol
Engine Coolant
Metabolized by alcohol dehydrogenase to glycoaldehyde —> glycolic acid —> glyoxylic acid and oxalic acid
Results in metabolic acidosis and cardiopulmonary compromise
GI decontamination NOT recommended
Pyridoxine (B6) and Thiamine (B1) both given IV at 100mg/day because low risk
Antidote: Fomepizole or Ethanol
Pediatrics - Methanol
Solvents, antifreeze, fuels, windshield washer fluid, etc.
Metabolized by alcohol dehydrogenase
Methanol —> formaldehyde —> formic acid
GI decontamination: NOT recommended
Folic Acid 1 mg/kg (max 50mg) every 4-6 hours for 24 hours because low risk
Antidote: Fomepizole or Ethanol
Ethylene Glycol and Methanol Antidotes
Impede alcohol dehydrogenase activity, preventing toxic aldehyde formation
Fomepizole: Load: 15 mg/kg, 10 mg/kg every 12 hours x 4 doses, 15 mg/kg every 12 hours until serum concentrations of toxic alcohol are <25 mg/dL
*4x as expensive as ethanol, but more cost effective because no ICU monitoring
*Less dosing errors
*Less monitoring
Ethanol (10%): Load: 8 mL/kg over 1 hour ; Infusion: 0.8 mL/kg/hour ; Serum concentrations of 100-150 mg/dL
*Requires central venous catheter
*Central nervous system depression
*Respiratory depression
*Therapeutic drug monitoring
Pediatrics - Household Cleaners / Caustic Exposures
2nd most reported exposure in children
• Household cleaners = bleaches, detergents, soaps
• Caustics = toilet cleaners, drain cleaners, oven cleaners
• GI decontamination: NOT recommended
• Antidote: none
• Management: supportive
If GI injury occurs, further medical and pharmacologic management (e.g., proton pump inhibitors) may be indicated
Pediatrics - Foreign Body Ingestion
Kind of self intuitive treatment (just read this once, maybe twice)
Examples: toys, disc batteries, ornaments
• GI decontamination: manual removal if esophageal impaction suspected
Disc batteries usually pass-through esophagus into the stomach and pass-through intestinal tract within 1-2 weeks
However, battery may become lodged in the esophagus and result in serious and life-threatening
complications such as burns, perforations and fistulae
Signs/Symptoms: vomiting, diarrhea, abdominal pain, fever, refusal to eat or drink, dysphagia
National Battery Ingestion Hotline
Pediatrics - Cough and Cold Products
Little, if any, evidence supports the use of cough and cold preparations in children for the
management of cold symptoms
• Often, children are given several drugs with similar ingredients, the dose measurement
was inaccurate, an adult formulation was used, or the child was given doses by multiple
caregivers
• 2007: FDA Advisory Panel recommended that these drugs be avoided in children younger than 6 years
• Gastric decontamination: Activated Charcoal
• Symptomatic management of hypertension (e.g., labetalol, nicardipine), arrhythmias (e.g.,
amiodarone), and seizures (e.g., benzodiazepines)
Why are most pediatric ingestions not serious?
Small volumes of products being ingested and often no intent to cause self harm result in less severe outcomes
Poison Prevention Counseling Points
Child proof caps
Child proof containers
Storage location
Environmental precautions
E.g. opening the garage door
Taking appropriate doses
Disposing of unused, expired drugs
Never mix household products
General Information to Collect During Overdoses
Valuable information to collect
‘ Age and weight
́ Health history
́ Time of exposure
́ Route of exposure (cutaneous, oral, etc.)
́ Present symptoms
́ Exact name of product, if available
́ Estimate to how much may have been ingested
́ Strength of product
́ Formulation of product (IR, XR, etc)
́ Occupation, as applicable
́ Suicide notes or similar
General Treatment Approach During Overdose
Assess the patient
́ Level of exposure
́ Amount
́ Symptoms
Self-treatment (at home)
́ Guidelines available for select exposures
Referral to hospital
́ Moderate to severe exposure
́ Intentional ingestions
ABCs of Overdose Management
• Airway
• Breathing
• Circulation
• Dextrose/Decontamination
• EKG/Elimination
Elimination Strategies
Pharmacologic Therapies
• Syrup of Ipecac (do not recommend use, no documented benefit, not commercially available)
• Activated Charcoal
• Whole Bowel Irrigation
Non-Pharmacologic Therapies
• Orogastric Lavage (stomach pump)
• Hemodialysis
• Other modalities
Activated Charcoal
Adsorbent
- 950 – 2000m2/g surface area
́ Dose: 1g/kg
́ Optimal time window*: 1 hour
*may be extended in select cases
́ Substances which will not bind
́ Ionized metals (e.g. Lithium)
́ Alcohols (ethylene glycol or methanol)
́ Gasoline
́ Sorbitol to improve palatability (only recommended for first dose if used, not subsequent doses)
́ Must have protected/secured airway (don’t want charcoal aspiration)
́ ADR: vomiting, black tarry stools
Not the OTC product
Whole Bowel Irrigation
Polyethylene glycol + Electrolytes
Colon prep at continuous rate
́ Dose: 1-2L/hr PO/NG until rectal effluent is clear
́ Goal is to minimize time in GI tract for absorption
́ Beneficial for XR products and body packers (drugs stored in GI tract across borders)
Orogastric Lavage
•“Stomach pumping”
•Optimally used when:
•Agent has potential to produce serious toxicity
•No antidotes exist
•Time window gives reason to believe agent may still be in stomach (usually 30 minutes-1 hour, hard to get to the hospital this fast)
•Not routinely initiated (because hard to satisfy these criteria for use)
Hemodialysis
•Extracorporeal elimination
•Optimally used when:
•Other elimination strategies not effective/contraindicated
•Agent has potential to produce serious toxicity
•Agent able to removed through filtration
•EXTRIP workgroup for guidance
Toxidromes
Adrenergic/ Sympathomimetic
Cholinergic
Sedative - Hypnotic
Anticholinergic
Opioid
Constellation of signs and symptoms that point to a class of toxin based upon understanding of pharmacology
́ Helps provide information in unknown overdose
́ Helps provide consistency in known overdoses
Anticholinergic Toxidrome
Mental Status: Decreased Agitation; Seizures
Dilated Pupils
Increased BP, HR, RR, Temperature
Decreased Bowel Sounds
Dry, Urinary Retention
(Dry as a bone, mad as a hatter… etc.)
Antidote:
́ Physostigmine* (Antilirium®)
́ Dose: 0.5mg – 2mg IV
́ MOA: Acetylcholinesterase inhibitor
́ *Current US manufacturer ceased operations. Unavailable unless imported from Germany
́ Other possible antidotes in research: Rivastigmine, Donepezil
Drugs: TCAs, Antihistamines
Cholinergic Toxidrome
Decreased mental status ; seizures
Pinpoint pupils
Decreased HR and BP
RR and Temperature vary
Bowel sounds present
Drugs: Organophosphates
S – salivation
L – lacrimation
U – urination
D – defecation
G – gastric cramps
E – emesis
Killer B’s
bradycardia
bronchorrhea
bronchospasm
Antidote:
Atropine
́ 1mg IV – titrate to effect
́ Inhibits muscarinic actions of acetylcholine
Bronchorrhea biggest target here
Pralidoxime (2-PAM)
́ 30mg/kg IV load
́ 8-10mg/kg/hr continuous infusion
́ Reactivates cholinesterase
Sedative-Hypnotic Toxidrome
Decreased mental status
Pupils, Temperature, Bowel Sounds vary
Decreased BP, HR, RR
Hyporeflexia
Drugs: Benzodiazepines and Ethanol
Opioid Toxidrome
Decreased mental status
Pinpoint pupils
Decreased everything: BP, HR, RR, Temperature, and Bowel Sounds
Hyporeflexia
Drugs: Morphine, Heroin
Adrenergic / Sympathomimetic Toxidrome
Alert/seizures Mental Status
Increased everything: BP, HR, RR, Temp, bowel sounds, diaphoresis and dilated pupils
Tremor
**Drugs: Cocaine, Amphetamines
Dangerous Agents without Typical Toxidromes
Acetaminophen
• Easy access – available OTC and in many combination products
• No toxidrome – must rule out exposure
• Obtain serum drug level with every intentional ingestion of ANY drugs/“handfuls”, etc.
• Obtain a 4-hour level (from time of ingestion)
• Potential to be fatal if untreated
Salicylates
• Easy access – available OTC and in many combination products
• Unique toxidrome – if not observant, may miss signs/symptoms
• Obtain serum drug level with every intentional ingestion of ANY drugs/handfuls, etc.
• Obtain serial drug levels – every few hours
• Potential to be fatal if untreated
Serum Drug Levels
We do not routinely obtain serum drug levels for all medications
́ No clinical utility
́ Levels may not result for days to weeks
Rule of thumb:
́ If the drug level will not affect the management of patient, don’t order or recommend them
́ Serum drug levels only obtained where the level will make a difference in care of
patient, commonly for narrow therapeutic index drugs. Examples:
́ Digoxin
́ Vancomycin
́ Phenytoin
́ Lithium
́ Acetaminophen**
́ Aspirin/salicylates**
Patient case example:
A 53 yo M comes in unresponsive following a presumed overdose. Empty medication bottles near patient include: Lisinopril 20mg, metoprolol tart. 25mg, sertraline 50mg, and haloperidol 5mg
The only serum drug levels obtained in this patient would be acetaminophen and salicylates
Urine Drug Screen
Serum drug level give quantifiable concentration information
Urine drug screens merely give positive or negative results
Limited by:
́ False positives
́ False negatives
́ Unknown quantity of ingestion
́ Unknown time from ingestion
́ May not provide whole story
́ Routinely obtained, but not routinely relied upon
False positives examples:
Pseudoephedrine causing amphetamine to be positive
Dextromethorphan causing phencyclidine (PCP) to be positive
