Badrinath Narayan, PEM Fellow Pediatric AHD, Aug 5 th 2014
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PEDIATRIC TOXICOLOGY Objectives Provide a general approach to
the poisoned patient History, physical, investigations Introduce
types of decontamination with indications/complications List Pills
that Kill
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Poisoning One of the most common medical emergencies
Exploratory behaviour Child abuse Environmental exposures Suicide
attempts In utero toxicants Pediatricians have a role in advocacy
Modes of exposure: Ingestion, ocular exposure, topical exposure,
envenomation, inhalation and transplacental exposure.
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Approach Brief window of opportunity to make critical
diagnostic and management decisions Prioritize critical assessment
and simultaneous management interventions
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14 year old female found unconscious in a park by friends The
patient is brought into the trauma bay at BCCH ED What would you
do?
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Primary Survey - ABCDEFG Apply monitors - O2, HR, RR, cycling
BP Obtain vitals: HR, RR, BP, O2 sat A Maintain patency, assess
reflexes, note GCS, have airway equipment ready B - Apply O2,
consider ETCO2, ABG C Assess perfusion, Get two large bore Ivs
Disability (GCS, pupil size and reactivity), ? Signs of trauma
Decontamination Drug Treatment dextrose, oxygen, narcan Bedside
Glucose
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Primary Survey Pay special attention to: Evidence of impaired
airway protective reflexes Many poisoned patients will vomit
Elective endotracheal intubation may be indicated at a lower
threshold Anticipate imminent respiratory failure Cyanosis/apnea
are late findings
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Case The patient has been stabilized What would you ask?
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History known intoxicant Take standard AMPLE history plus: What
was ingested, How much, When, Why? Obtain prescription bottles when
possible, and be sure that bottles contain med listed Talk to
patients family and friends in ED/contact home Ensure belongings
are looked at to identify paraphernalia In a toddler think single
pills, in an adolescent think co-ingestions!!
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When to suspect? Suspected but unknown intoxicant: Acute onset
of illness Pica-prone age (1-5) History of pica, ingestions Current
household stress Significantly altered mental status Family
medications/recent illnesses Social: grandparents visiting, holiday
parties, other events
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Case On exam what things might you see to suggest a
toxicological cause for the childs presentation?
Removal of toxic substance Decontamination: Removal of a
substance prior to entry into the circulation Elimination: Removal
of a substance by enhanced excretion once it has entered the
circulation
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Approach to decontamination Get help -- Poison control centre
24-hour Line: 604-682-5050 or 1-800- 567-8911 Healthcare
professionals only line: 604-707-2787 or 1-866-298-5909 (outside
the Lower Mainland) Monday to Friday from 9 am - 4 pm
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Forms of Decontamination Topical flush aggressively (ocular or
skin), remove contaminated clothing Dilution Ipecac (no longer
recommended; AAP statement against it) Activated Charcoal Gastric
Lavage also fallen out of favour Whole Bowel Irrigation
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Dilution Indicated if toxin produces only simple irritation
Controversial for caustic agents May be used in first few minutes
NOT for drugs may increase absorption Not if upper airway
compromise Water or milk E.g. dish soap
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Activated Charcoal Activation increases surface area of
particles Toxins adsorb to activated charcoal decreasing amount
adsorbed by the body Some toxins are not well adsorbed most small
molecules Iron, the alcohols, lithium, strong acids and alkali,
sodium, chloride. Dose: 10:1 charcoal to drug ratio. For unknown
ingestions dosing is based on ability to tolerate the agent:
Children - 1 gram/kg of body weight.
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Activated Charcoal Timing If not contraindicated there does not
seem to be a reasonable time that is too late to give AC,
especially with SR or DR products Dogma used to be an hour but
studies with respect to delayed gastric emptying have challenged
this data Multiple-dose activated charcoal sustained-release
products useful with drugs with low Vd, low protein binding, long
half-life
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Activated Charcoal Activated charcoal not useful with: P
esticides H ydrocarbons A cids, Alkali, Alcohols I ron L ithium,
Liquids S olvents
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Activated Charcoal Contraindications absent gut motility or
perforation if endoscopic visualization is required (e.g. caustic
ingestions) loss of protective airway reflexes Complications fatal
aspiration small bowel obstruction
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Gastric Lavage Orogastric lavage with a large bore tube (36-40
F for adult; no smaller than 22-24 F for children) RARELY
recommended not been demonstrated to improve outcome, several risks
Might be considered: VERY early or after very dangerous ingestions
(colchicine, arsenic) Ensure airway protected Place patient in left
lateral decubitus position with the head down Have suction
available for secretions Place tube (tragus-nose-xyphoid) and
confirm position Lavage until fluids clear
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Whole Bowel Irrigation Whole bowel irrigation of the entire GI
tract by instillation of large volumes of fluid Usually takes hours
Has been used safely in children Most useful for substances with
delayed absorption ( i.e. extended release ), not amenable to
activated charcoal and with body stuffers/packers
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Whole Bowel Irrigation Accomplished by orally taking (or
through NG) large volumes of Nulytely (approved for children and
adults), Colyte, or Golytely Adolescents: mininum of 1.5-2 L/hour
Children: 25 mL/kg/h Give until rectal effluent is clear.
Forms of Elimination Urine alkalinization - promotes excretion
of salicylate, enhances clearance of some drugs Dialysis Charcoal
Hemoperfusion
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Dialysis Consider nephrology consult with dialysis if: S
alicylates T heophylline U remia M ethanol B arbiturates L ithium E
thylene Glycol
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Antidotes PoisonAntidote AcetaminophenN-acetylcysteine
AnticholinergicsPhysostigmine CholinergicsAtropine
BenzodiazepinesFlumazenil Carbon monoxideOxygen CyanideAmyl
nitrite, sodium nitrite, sodium thiosulfate, hydroxycobalamin
DigoxinDigoxin-specific Antibodies Ethylene
glycolEthanol/fomepizole, thiamine and pyridoxine PoisonAntidote
Heavy metalsDimercaprol (BAL), EDTA, penicillamine Hypoglycemic
agents Dextrose, sucrose, octreotide IronDeferoxamine mesylate
IsoniazidPyridoxine MethanolEthanol/fomepiz ole, folic acid
Methemoglobin emia Methylene blue OpioidsNaloxone Organophospha tes
Atropine, pralidoxamine Avoid physostigmine if TCA ingestion
present - has potential to worsen ventricular conduction defects
and to lower seizure threshold.
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Investigations Select tests only Help confirm diagnosis Help
monitor Help identify silent killers Tox screens not useful in
acute management
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Investigations All symptomatic patients with unknown ingestion
should get electrolytes, glucose, osmolarity, acetaminophen/ASA
levels, blood gas, EKG All suicidal patients should get
acetaminophen level (~1:500 patients without a history of APAP
ingestion will have a potentially toxic blood level - NYPCC) and
ASA level Other tests based on history, physical, level of
suspicion CBC Specific drug levels Urinanalysis BHCG Calcium, liver
function panel
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Increased anion gap metabolic acidosis (Na (Cl + HCO3) M
ethanol (hx of alcohol abuse, methanol level), metformin U remia
(BUN) D KA, AKA, SKA (hx; urine ketones) P araldehyde (distinctive
odor) I soniazid (seizure; lactate level) L actic acidosis E
thylene glycol (level) S alicylates/solvents (level)
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Increased Osmolar gap (serum calculated) Two salts and a sticky
BUN M annitol A lcohols D ye G lycerol A cetone S orbitol
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Pitfalls of osmolar gap Cannot distinguish between type of
toxic alcohol Insensitive in late presentations Not sufficiently
sensitive to exclude small ingestion Cannot rule out ingestion
based on a normal OG
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Radio-opaque drugs Chloral Hydrate Opioid packets (latex) Iron
and other heavy metals Neuroleptics Sustained release
tablets/Salicylates
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ECG Findings include: Toxicologic tachcyardia/bradycardia QRS
widening Prolonged QT (www.qtdrugs.org) Findings can develop late
so obtain serial ECGs
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Case A 2 year old girl is found playing with his grandmothers
pill box. Some pills may be missing and a powder residue is found
in the childs mouth. What medications would most concern you if
this child ate just one pill?
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Small dose toxins SubstanceMajor symptomSymptom onset
Medications Beta-adrenergic antagonists(sustained release)
Bradycardia, hypotensionDelayed, up to 24 hours
Buproprion(sustained release)Seizure, cardiovascular
collapseDelayed up to 24 hours CCB (sustained release)Bradycardia,
hypotensiondElayed, up to 24 hours ClonidineApnea, bradycardia,
hypotension1-2 hours Lomotil (Diphenoxylate/Atropine)ApneaDelayed,
up to 24 hours Methylsalicylate (oil of wintergreen)Metabolic
acidosis, pulmonary/cerebral edema 1-6 hours Opioids: extended
release preparationsApneaDelayed, up to 24 hours Methadone1 2 hours
SulfonylureasHypoglycemiaDelayed, up to 24 hours
TheophyllineSeizure, hypotensionDelayed, up to 24 hours Other
agents CamphorSeizureMinutes to hours PesticidesSLUDGEMinutes to
hours Toxic alcoholsBlindness, renal failure, metabolic acidosis3 8
hours (ethylene glycol) 3 18 hours( methanol) ONE PILL KILLERS
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Case A 3 yo male presents to the ED comatose with a GCS of 6.
He was found on the bathroom floor. Following stabilization, what
is the most immediate course of action? A. Head CT B. ECG C. Tox
screen D. Broad spectrum Abx