Poisoning
As part of well-child care, discuss preventing and treating poisoning with parents (e.g., “child-proofing”, poison control number).
In intentional poisonings (overdose) think about multi-toxin ingestion.
When assessing a patient with a potentially toxic ingestion, take a careful history about the timing and nature of the ingestion.
When assessing a patient with a potential poisoning, do a focused physical examination to look for the signs of toxidromes.
When assessing a patient exposed (contact or ingestion) to a substance, clarify the consequences of the exposure (e.g., don’t assume it is non-toxic, call poison control).
When managing a toxic ingestion, utilize poison control protocols that are current.
When managing a patient with a poisoning,
Assess ABC's,
Manage ABC's,
Regularly reassess the patient’s ABC’s (i.e., do not focus on antidotes and decontamination while ignoring the effect of the poisoning on the patient).
General Overview
ABC, Oxygen, Mental status
Vitals q5 mins
Temperature, glucose
IV access
Consider avoid intubation if only low GCS and do not expect airway compromise
Cardiac monitor, EKG
On Exam: Pupil size, Skin temperature/moisture, Neuro (r/o CNS event)
Rule out head/body injury (C-spine)
DON'T forget in Universal Antidotes in altered mental status: Dextrose, Oxygen, Naloxone (Narcan), Thiamine
Dextrose can be given 50mL of D50W, if no IV access can give Glucagon 1mg IM
Oxygen, 100% O2 in carbon monoxide poisoning
Naloxone in life-threatening is 2mg initially up to 10mg, or if non-life-threatening 0.1mg initially doubled every two minutes up to 10mg
Caution with naloxone in multi-drug poisonings or opioid addiction (unmasking other symptoms)
Thiamine (B1) given 100mg IV/IM/PO with 25g dextrose (50mL of D50W) to prevent Wernicke's encephalopathy
Suspect thiamine deficiency in malnutrition (alcoholics, anorexics, hyperemesis of pregnancy)
History
Patient often unreliable – use collateral sources (paramedics, police, family, friends, pharmacist)
Who - patient's age, weight, PMH (alcoholism, renal or hepatic disease)
What - name, dosage of medications (including OTC) or substances, coingestants, amount
When
Where - Injection or ingestion
Why - intentional vs unintentional
Commonly ingested nontoxic substances
Personal care products: Soap, shampoo, lipstick, lotion, perfume (low alcohol), eye makeup, toothpaste, deodarant
Household items: Thermometers (glass potentially harmful), pen ink, crayons, chalk, candles, pencils/erasers, laundry detergent, fabric softener, bleach
Suspect Overdose in altered mental status, dysrhythmia, trauma, bizarre presentation
GI Decontamination
Activated charcoal within 1h-2h
Most effective gastric decontamination
Contraindications: Nontoxic ingestion, poisons not bound by AC (Caustic acids and alkalis, alcohols, lithium, heavy metals), high risk of aspiration
Dose: 1 to 2g/kg
Multiple dosing q2-6h effective in phenobarbital, phenytoin, carbamazepine, salicylates, digitalis, theophylline and dapsone
Whole bowel irrigation
Indications: Toxic foreign bodies (drugs packets), sustain release drugs, or toxic materials not bound by AC
Contraindications: Mechanical obstruction, ileus, perforation
Isotonic PEG 2L/hour, if emesis occurs can reduce rate by 50%, continue until effluent clear (or passes charcoal if it was given)
Gastric lavage within 1h with AC after
Indications: Highly toxic substances or large ingestions, substances not adsorbed by activated charcoal (lithium, iron, lead, methanol) and potential jeopardized airway (altered mental status)
Contraindications: Ingestion of corrosives, hydrocarbons, depressed gag reflexes who are not intubated, clinically insignificant ingestions
Complications: Aspiration, perforation of esophagus/bronchus
No longer recommended: Syrup of Ipecac, Cathartics, Dilution
Investigations
Labs
CBC, electrolytes, glucose
Hepatic and renal function
High creatinine with normal BUN consider isopropyl alcohol or DKA
Urinalysis
Serum osmolarity
Osmolar gap = Measured - (2 x [Na+] + [glucose] + [urea]) > 10
Methanol
Ethylene glycol
Sorbitol
Polyethylene glycol (IV lorazepam)
Propylene glycol (IV lorazepam, diazepam and phenytoin)
Glycine (TURP syndrome)
Maltose (IV IG – Intragram)
VBG + lactate
AGMA ([Na+] – [Cl−] – [HCO3−]>12)
Methanol
Uremia
DKA
Paraldehyde
Iron, Ibuprofen, INH
Lactate
Ethylene glycol
Salicylates
Quantitative drug serum levels: Acetaminophen, Salicylates, Ethanol
Other: Digoxin, iron, lithium, theophylline, anticonvulsants, methanol, ethylene glycol
Qualitative urine drug screen
Pregnancy test
Other
EKG
QRS, QTc
CXR for aspiration, or medications (salicylates, narcotics, sedative-hypnotics) for pulmonary edema
Supportive Care
Hypotension - IV fluids or pressors (norepinephrine)
Hypertension - Benzodiazepines in agitated, or CCB (avoid BB alone for unopposed alpha-adrenergic stimulation and vasoconstriction)
Ventricular tachycardia - Sodium bicarbonate in TCA and magnesium sulfate in Digoxin (with Digibind)
Bradyarrhythmnia - Atropine/Pacing
Consider calcium, glucagon, high dose insulin in CCB or BB intoxication
Seizure - Benzodiazepines (Barbiturates if needed), avoid phenytoin
Consider glucose for hypoglycemic agents
Pyridoxine for isoniazid toxicity
Agitation - Benzodiazepines, Haldol
Consider Physostigmine for anticholinergic
Hyperthermia - Ice water immersion or cooling (especially in sympathomimetic, serotonin syndrome or neuroleptic malignant syndrome)
Hemodialysis
Salicylates, ethylene glycol, methanol, lithium, acidosis or hyperkalemia
Observe in Emergency Department for 6 hours, if severe consult ICU
Clinical syndromes (Consider antidotes once STABLE)
Excitation (high HR, BP, RR, T)
Anticholinergic, sympathomimetic, hallucinogenic, drug withdrawal
Treat with benzodiazepines and supportive care
Depression
Ethanol, sedative-hypnotic, opiates, cholinergic (parasympathomimetic), sympatholytics, toxic alcohol (methanol, ethylene glycol)
Mixed
Polydrug or metabolic (hypoglycemic, salicylate, cyanide), antiarrhythmic, or multiple drugs with multiple mechanisms of action (TCA)
Acetaminophen (Tylenol)
Toxic above 150mg/kg (7.5-10g for an adult)
Clinical manifestations:
0.5-24h: Asymptomatic (possible nausea, vomiting, diarrhea)
24-72h: RUQ pain (hepatic injury)
Investigations:
Initial and more importantly >4h Acetaminophen Level evaluate on Rumack-Matthew normogram
ALT and INR (if ALT abnormal)
Treatment:
Activated Charcoal 50g within 2h (up to 4h) of ingestion unless contraindicated (unable to protect airway)
N-acetylcysteine (NAC, Mucomyst)
If known time of ingestion, and above treatment line as per normogram
Time of ingestion not known or >24h, or chronic ingestion, treat if any acetaminophen concentration or abnormal AST/ALT
First dose, if serum level not available until >8h post-ingestion
Continue NAC if serum acetaminophen >10mcg/mL or elevated AST/ALT
ANY signs of liver injury (preferable to start NAC prior to elevated ALT)
Salicylate (Aspirin)
Fatal above 10g in adults, 3g in children
Clinical manifestations:
Tinnitus, tachypnea, vertigo, vomiting, diarrhea
Respiratory alkalosis initially, mixed, then metabolic acidosis
Investigations:
Serum salicylate levels >40mg/dL (2.9mmol/L) possible toxicity
Measure q2h until decreasing, below 40mg/dL, asymptomatic and normal respiratory effort
Blood gas
Treatment:
AVOID intubation (risk of neurotoxicity in acid pH from apnea)
Consider multi-dose activated charcoal in enteric-coated (50g q4h)
Alkalinization (serum and urine) with IV sodium bicarbonate (3 amps NaHCO3 in 1L D5W at maintenance rate x 2 )
Target urine pH >7.5 (repeat q1h)
Monitor for hypokalemia
Glucose especially if altered mental status
Early nephrology for possible dialysis
Methanol, ethylene glycol
Clinical Manifestations:
Profound metabolic acidosis (HCO3<8mEq/L) and osmolal gap (>25mOsm), status epilepticus, shock, ischemic bowel
Visual blurring, scotoma, blindness -> Methanol
Flank pain, hematuria -> Ethylene glycol
Investigations
Blood gas
Electrolytes (anion gap), serum osmolality, ethanol (determine osmolal gap), calcium (ethylene-glycol associated hypoglycemia)
Methanol, ethylene glycol and isopropranol
Urinalysis (oxalate crystals)
Treat:
Fomepazole (alcohol dehydrogenase inhibition) or ethanol
Sodium bicarbonate
Hemodialysis in severe toxicity
Benzodiazepine poisoning
Rarely toxic, rule out coingestant
Risk of propylene glycol poisoning if receiving large IV BZDs (used as a diluent)
Investigation:
Urine BZD identifies metabolites of 1,4-BZD (oxazepam), may not detect clonazepam, lorazepam, midazolam, alprazolam
Treatment:
Intubate if needed
Naloxone in mixed overdose
Consider avoid Flumazenil given risk of seizures in chronic benzodiazepine use
Avoid GI decontamination (risk of aspiration) unless airway protected and coingestant treatable by charcoal
Beta blocker/Calcium Channel Blocker
Clinical manifestation
Bradycardia, hypotension, shock
CCB may cause hyperglycemia, BBl may cause hypoglycemia
Cardiogenic vs. Vasodilatory shock
Bedside ultrasound to check cardiac contractility (if normal contractility and hypotension, suspect vasodilation as cause of shock)
Treatment (if severe can give all below simultaneously)
Airway
Central vascular access (ideal for D50W, calcium, vasopressors)
Fluids if hypovolemic (uncommon)
Vasopressors
Epinephrine 0.1mcg/kg/min titrate up rapidly
Norepinephrine may be useful in vasodilation
Glucagon or milrinone may be helpful in BBI, bradycardia and cardiogenic shock (unlikely to help in vasodilatory shock from CCB intoxication), anticipate vomiting
Glucagon 5mg IV over five minutes, may be repeated, if hemodynamic improvement can do continuous infusion at 5-10mg/hour
Consider milrinone when not enough glucagon is available
Calcium gluconate 3g IV over>5mins q10 mins PRN, up to max 9g (or calcium chloride 1g IV up to 3g)
Atropine 1mg IV (up to 3 doses), unlikely to work
HyperInsulinemic Euglycemia (HIE) should be started early as response may take 60mins
Insulin 1 unit/kg IV bolus, followed by a 1 unit/kg/hour infusion, can titrate up every 10 minutes within a range of 1-10 units/kg/hour (targetting HR and BP)
D50W 1-2 ampules (50-100mL) IV ideally via central line, then can start infusion at 1mL/kg/hour (or intermittent ampules), target glucose 7-14
Target potassium >3 (but remember when insulin is stopped potassium will shift out of cells and may lead to hyperkalemia)
Monitor magneisum and phopshate
IV lipid emulsion
Opioids
Clinical manifestatios
Respiratory depression
Miotic pupils (coingestants may make pupils normal/large)
Treatment:
Ventilate before Naloxone
Naloxone (Narcan) titrated to RR>12 (not until normal LOC)
Consider very small doses 0.04mg IV (or IO/IM/SC) q1min
In cardiorespiratory arrest, no evidence of benefit, may consider 2mg IV (or IO/IM/SC) q1min
If overshoot, manage withdrawal symptoms expectantly (not with opioids)
If no effect after 5-10mg consider other diagnoses
Other
Antipsychotics (acute dystonic reaction) -> Benztropine, diphenhydramine
Anticholinergic -> Physostigmine salicylate (Antilirium)
Organophosphates, Carbamates (Cholinergic) -> Atropine, Pralidoxime
Digoxin -> Digoxin immune Fab (Ovine, Digibind)
Consider MgSO4 to stabilize if delay in digoxin antibodies
Iron -> Deferoxamine (Desferal)
TCA (Cardiotoxicity, convulsion, coma)-> Sodium Bicarbonate 1-2mEq/kg
Cocaine, Methamphetamins, amphetamines (sympathomimetic) -> Rapid cooling, Benzos, Fluids + Nitroglycerine infusion
Cyanide -> Hydroxocobalamin 5g, Sodium nitrite 300 mg., Sodium Thiosulfate 12.5g, 100% oxygen
Well-child care
Keep items locked and out of reach/sight
Keep in original containers (safety lids)
Don’t take medications in view of children
Don't refer to medicine as “candy”
References:
Tylenol overdose: http://www.asem.org.au/document.php/njxudmy/Paracetamol+Overdose+Treatment+Nomogram.pdf
World directory of poison centres, as of 31 August 2016. http://apps.who.int/poisoncentres/