Download Approach to Poisonings

Approach to Poisonings
Robert J. Vinci, MD
Background
• 2 – 5 Million exposures per year
• 4% require hospitalization
• 96% minor or no effects
Background
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93% involve a single substance
67 % patients < 20 years of age
53% children < 6 years of age
25% children < 2 years of age
Bimodal Pediatric age distribution
Household products vs. pharmaceuticals
Fatalities
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Cleaning substances
Analgesics
Antidepressants
Heavy metals, especially iron
Street drugs
Cardiovascular drugs
Alcohols
How do Children Present?
• Vague History
• Change in mental status
• Suspicion of Ingestion
– Open bottles
– Pills on floor
– Missing medications
• Directly Observed
Initial Evaluation
• History
– When
– How Much
– Symptoms
– Meds in the Home
– Any other possible exposures
– Observations from EMS personnel
Initial Evaluation
• History
– Seizures
– GI symptoms
– Hallucinations
– Toxidromes
Initial Evaluation
• Physical Examination
– ABC’s – Rapid deterioration
– Review vital signs for clues
– Mental Status
– Pupils
– Nystagmus
– Skin Color/Skin Warmth
Initial Evaluation
• Laboratory Studies
– Pulse Oximetry
– EKG
– Electrolytes/Blood Sugar
– ABG’s
– Toxic Screen/Drug Levels
– Serum osmolality/osmolal gap
Increased Anion Gap Acidosis
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Methanol
Ethylene Glycol
Salicylates
Iron, INH, Ibuprofen
Drugs producing hypotension and lactic
acidosis (many serious ingestions)
Increased Osmolal Gap
• Osmolal Gap = Osm (calc) – Osm (meas.)
• Osmolal Calc. = 2 x Na + Gluc + BUN
18
2.6
• Increased Osmolal Gap
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Ethanol
Methanol
Ethylene Glycol
Acetone
Radiographic Studies
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CHIPES
C=
Chloral Hydrate
H=
Heavy Metals, especially Iron
I=
Iodinated compounds (thyroxin)
P=
Psychotropic, Packers
E=
Enteric Coated Medications
S=
Salicylates, Sustained Release
Toxidromes
• Hyperthermia, agitation,
mydriasis, hypertensive
hyperthermic
• Coma, Seizures, arrhythmia
• Coma, respiratory depression,
myosis
• Hallucinations, mydriasis, hot
dry skin, urinary retention,
tachycardia
• Sympathomimetics
• Tricyclics
• Opiods
• Anticholinergics
Serum Toxic Screens
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Aspirin
Salicylates
Alcohols
Tricyclics
Urine Toxic Screens
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Benzodiazepines
Barbiturates
Opiates
PCP
Marijuana
General Management
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Supportive Care
Oxygen
Intravenous glucose
Careful monitoring for potential side
effects
Specific Management
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Gastric Emptying
Decrease Absorption
Enhance Elimination
Specific Antidotes
Gastric Emptying
• Syrup of Ipecac
– Stimulates Gastric Receptors linked to the CNS
vomiting center
– Emesis within 20 minutes
– 80% after a single dose
– 99% after two doses
– Vomiting persists for 1 – 2 hours and may delay
use of oral antidotes and treatments
Syrup of Ipecac
Should it be Used?
• Adverse Effects
– Uncontrolled vomiting/ Mallory Weiss Tear
– Sedation
– Fatal aspiration
• 30% recovered < one hour of ingestion.
Minimal toxin recovered after 90 minutes
• No true evidence it improves outcome
• Not studied well with delayed gastric
emptying or decreased peristalsis
When to Consider Ipecac
• Alert, conscious children > 6 months of age
• Ingestion of potentially toxic amount of
poisoning
• Within 60 minutes of ingestion
• Perhaps at home or in pre-hospital setting
• Limited value in the hospital setting
Syrup of Ipecac
Contraindications to Use
• Substance that produces rapid change in
mental status
• Calcium channel blocker, digitalis, betablocker (worsen bradycardia of vomiting)
• Corrosives
• Mental Status changes/Decreased Gag
• Coagulopathy
• Infants less than 6 months of age
Ipecac
Adverse Effects
• Protracted vomiting, sedation or diarrhea
• Forceful vomiting (Mallory-Weiss tears,
pneumomediastinum, bradycardia)
• Sedation or seizures leading to aspiration
• Cardiomyopathy with chronic abuse
• May delay oral therapy, especially charcoal
Gastric Lavage
• Need Presence of gag – now and during the
procedure
• Left Lateral Decubitus/Trendenburg
• Large Bore Single Lumen tube
• After confirming position of tube, 10 – 15
ml/kg aliquots of saline until clear
• Removes < 30 % of what is ingested (similar
to ipecac)
• Similar contraindications to ipecac
Gastric Lavage
Contraindications
• Corrosives
• Uncooperative child
• History of GI surgery/pathology
Gastric Lavage
Technique
• Confirm presence of gag reflex
• Left lateral decubitus position with head
lower than feet
• Largest possible tube
• Lavage with aliquots of 10 ml/kg until
clear
Charcoal - Adsorbent
• Binding surface areas of 3000 m2/gm
• Maintains attachment through covalent
bonding
• If treatment occurs within one hour as much
as 75% of toxin is adsorbed
• Dose is 10:1 ratio, however a fixed dose of
1 gram/kg is recommended
• May mix with flavoring to hide taste
• ?Use with NG tube????
Use of Charcoal
• 1 gm/kg of body weight
• Often pre-mixed as aqueous solution or with
a cathartic such as sorbitol
• May flavor with cola, chocolate syrup in
order to make it more palatable
• More effective than ipecac or gastric lavage
• Greatest benefit if used within one hour of
ingestion
Charcoal
“Contraindications”
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Hydrocarbons
Alcohols
Heavy Metals (Iron)
Minerals
Corrosives (makes endoscopy difficult)
GI perforation
Multiple Dose Activated Charcoal
• Drugs which decrease gastrointestinal
mobility
• Enterohepatic circulation
• Gastric Dialysis
• Give 0.5 mg/kg of charcoal without
sorbitol every 4 – 6 hours
Adverse Effects of Charcoal
• Aspiration
• Diarrhea, if used with sorbitol
• Fluid loss and electrolyte abnormality
Cathartics
• Osmotic Agents used to treat ingestions
• Increase Gastric Motility
• In pediatric patients the use of cathartics
should be limited to the first dose of
charcoal
Magnesium Citrate
• 4 ml/kg of 6% suspension
• Larger doses do not improve efficacy
• Magnesium does get absorbed
Sorbitol
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The most efficient osmotic agent
1 – 2 grams/kg
Not recommended in children < 1 year
May cause hypernatremic dehydration
and cardiovascular collapse
Whole-Bowel Irrigation
• Polyethylene glycol-electrolyte solution
• There is no absorption
• Large volumes infused (500 – 1000 ml
per hour) until effluent is clear
• Treatment of choice for agents which
are not well absorbed by charcoal
Indications
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Enteric coated pills
Sustained release tablets
Illicit drug packets
Drug concretions
Ingestions of substances poorly bound
by charcoal
Common Antidotes
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Opiate Overdose
Acetominophen
Salicylates
Digoxin
Iron
INH
Ethylene Glycol
Tricyclics
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Narcan
N-acetylcysteine
Alkalinization
Fab Antibodies
Deferoxamine
Pyridoxine
Fomepazole
Sodium Bicarbonate
Approach to Patients
• Avoid the use of ipecac
• Gastric lavage has not been shown to be
effective
• In general, activated charcoal is the sole
intervention necessary to treat serious
poisonings. This may be used with or
without a cathartic
Poison Control Centers
• 1-800-222-1222
• 617-232-2120
• May be helpful in identification of
toxins based on symptoms alone