Approach to a child with Unknown Poisoning

Algorithm

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graph TD

classDef start fill:#1b5e20,color:#ffffff,stroke:#66bb6a;
classDef step fill:#0d47a1,color:#ffffff,stroke:#42a5f5;
classDef decision fill:#4a148c,color:#ffffff,stroke:#ab47bc;
classDef alert fill:#b71c1c,color:#ffffff,stroke:#ef5350;

A(Poisoned Child
Emergency Presentation):::start
B{Hemodynamically Stable}:::decision
C[Emergency Resuscitation
Airway Fluids Vasopressors]:::alert
D[Bedside Interventions
Glucose and Naloxone trial]:::step

A --> B
B -->|No| C
C --> D
B -->|Yes| D

D --> E{Clinical Action Path}:::decision

E -->|History Exam| F1[Toxidrome Identification
Assess odors and mucosa]:::step
E -->|Diagnostics| F2[Labs and Imaging
ECG and Gap Analysis]:::step
E -->|Management| F3[Decontamination
Dermal Ocular or GI]:::step

F1 --> G1[Antidotal Therapy
Atropine Flumazenil etc]:::step
F2 --> G2[Toxin Screening
Salicylates Acetaminophen]:::step
F3 --> G3[Enhanced Elimination
Dialysis or Alkalinization]:::step

Initial Stabilization And Resuscitation

• Emergency cardiorespiratory stabilization precedes comprehensive diagnostic testing.
• Require rapid systematic assessment of airway, breathing, circulation, and neurological disability upon presentation.
• Anticipate early elective endotracheal intubation for profound central nervous system depression, absent protective airway reflexes, or acute respiratory failure mitigating pulmonary aspiration risk.
• Manage hypotension aggressively initially using rapid intravenous boluses of isotonic crystalloids including normal saline or lactated Ringer's.
• Utilize direct-acting vasopressors including epinephrine or norepinephrine if hypotension remains refractory to volume expansion.
• Prefer vasopressors particularly if suspecting tricyclic antidepressant or calcium channel blocker toxicity.
• Perform mandatory bedside serum glucose test for altered mental status.
• Treat profound neuroglycopenia immediately using intravenous dextrose; condition perfectly mimics toxic encephalopathy.
• Initiate diagnostic and therapeutic trial of naloxone in cases featuring unexplained coma or significant respiratory depression reversing potential opioid intoxication.

Clinical Evaluation And History Taking

Epidemiological And Historical Clues

• Analyze child's age providing critical epidemiological context.
• Under 5 years: Exposures predominantly accidental, often involving single agents including common household products, cosmetics, or unsecured pharmaceuticals.
• Adolescents: Ingestions largely intentional, driven by suicide attempts, substance abuse, or misuse, frequently involving severe polypharmacy.
• Reconstruct scene via meticulous history.
• Establish exact location child found.
• Explore accessibility of medications belonging to older relatives or visitors.
• Screen for underlying psychiatric stress or previous suicide attempts in older youths.

Physical Examination And Diagnostic Odors

• Perform targeted physical examination identifying classic toxidromes.
• Assess characteristic odors on breath or clothing.
• Bitter almonds: Suggest cyanide.
• Acetone: Suggest salicylates or isopropyl alcohol.
• Garlic: Point to organophosphates or arsenic.
• Mothballs: Indicate camphor or naphthalene exposure.
• Inspect oral cavity revealing excessive salivation suggesting organophosphates or ketamine.
• Identify oral mucosal burns indicating caustic or corrosive ingestion.
• Detect pigmented gum lines establishing hallmark of heavy metal poisoning including lead, mercury, or bismuth.

Major Toxidromes And Clinical Features

Diagnostic And Laboratory Evaluation

Basic Investigations

• Require comprehensive laboratory testing assessing multi-organ dysfunction and screening specific highly toxic occult substances.
• Include complete blood count, serum electrolytes, blood urea nitrogen, serum creatinine, liver transaminases, and blood gas analysis.

Acid-Base And Osmolar Gap Analysis

• Calculate anion gap evaluating high anion gap metabolic acidosis revealing unmeasured toxic anions.
• Identify toxins causing high anion gap metabolic acidosis

• Determine osmolar gap indicating unmeasured osmotically active substances including toxic alcohols like methanol, ethanol, ethylene glycol if elevated greater than 10 mOsm.

Electrocardiography

• Utilize 12-lead electrocardiography rapidly assessing life-threatening cardiotoxicity and specific conduction delays.
• Widened QRS interval suggests dangerous fast sodium channel blockade, classic finding in severe tricyclic antidepressant toxicity requiring immediate intervention.
• Prolonged QTc interval demonstrates interference with potassium rectifier channels predisposing to torsades de pointes.
• Observe prolonged QTc frequently with methadone, phenothiazines, and antipsychotics.

Specific Toxicology Screening And Radiography

• Recommend quantitative serum screening for acetaminophen and salicylates in all cases of intentional or unknown poisoning.
• Note early acetaminophen and salicylate toxicity may remain asymptomatic but highly amenable to time-sensitive antidotal therapy.
• Note limited utility of urine drugs-of-abuse screens for acute management due to inherent delays and high false positive/negative rates.
• Utilize plain abdominal radiography visualizing specific radiopaque toxins.

Decontamination Strategies

Dermal And Ocular Decontamination

• Mandate immediate, extensive flushing using tepid water or normal saline for minimum 10-20 minutes.
• Strictly avoid water irrigation for highly reactive compounds including elemental sodium, phosphorus, calcium oxide, and titanium tetrachloride.

Gastrointestinal Decontamination

• Individualize decontamination based on suspected toxin properties, exposure route, clinical stability, and time elapsed.
• Consider syrup of ipecac obsolete and contraindicated; produces variable toxin removal, delays definitive treatments, causes significant adverse outcomes.
• Utilize gastric lavage rarely; consider only within 1 hour of massive, potentially lethal ingestion.
• Avoid gastric lavage strictly in unprotected airway, corrosive ingestion, or volatile hydrocarbon exposure due to extreme aspiration and perforation risk.

Activated Charcoal

• Represents single most effective gastrointestinal decontamination method.
• Achieves maximum efficacy administered within 1 hour of toxin ingestion.
• Requires completely patent and protected airway prior to administration preventing catastrophic pulmonary aspiration.
• Dose at 1 g/kg.
• Acts via physical adsorption onto highly porous surface.
• Ineffective binding heavy metals, iron, lithium, mineral acids, strong alkalis, toxic alcohols, cyanide, and most hydrocarbons.

Whole-Bowel Irrigation

• Instill massive volumes of polyethylene glycol electrolyte solution via nasogastric tube.
• Administer 35 mL/kg/hr in children and 1-2 L/hr in adolescents.
• Clears gastrointestinal tract of substances poorly adsorbed by charcoal including iron, heavy metals, lithium, sustained-release pharmaceuticals, and illicit drug packets.

Techniques For Enhanced Elimination

Urinary Alkalinization

• Enhances renal excretion of weak acids trapping ionized, polar molecules within renal tubules preventing systemic circulation reabsorption.
• Accomplish administering continuous intravenous sodium bicarbonate infusion maintaining target urine pH 7.5-8.0.
• Serves as primary elimination strategy for severe salicylate, phenobarbital, and methotrexate toxicity.

Hemodialysis And Hemofiltration

• Clears toxins possessing low volume of distribution, low molecular weight, low plasma protein affinity, and high water solubility rapidly.
• Indicated specifically for severe, life-threatening poisonings involving toxic alcohols, lithium, salicylates, theophylline, and barbiturates.

Multiple-Dose Activated Charcoal

• Accelerates systemic toxin clearance interrupting enterohepatic circulation.
• Utilizes intestinal mucosa as gastrointestinal dialysis membrane pulling toxins back into gut lumen.
• Administer 0.5 g/kg every 4-6 hours.
• Recommend for life-threatening ingestions involving carbamazepine, dapsone, phenobarbital, quinine, and theophylline.

Intravenous Lipid Emulsion

• Creates intravascular lipid sink sequestering highly fat-soluble toxins.
• Reduces active concentration mitigating target organ impact.
• Utilize as profound lifesaving intervention in severe cardiotoxicity secondary to bupivacaine, massive calcium channel blocker overdoses, and tricyclic antidepressant poisonings.

Diagnostic Trials And Antidotal Therapy

• Administer specific, carefully titrated antidotes serving as lifesaving therapeutic intervention and definitive diagnostic tool in undifferentiated comatose child.
• Utilize naloxone starting at 0.1 mg/kg intravenous dose for presumed opioid toxicity characterizing profound respiratory depression and pinpoint pupils.
• Mandate significantly lower naloxone doses if chronic opioid dependence suspected preventing precipitation of severe acute withdrawal.
• Administer flumazenil 0.01 mg/kg reversing severe benzodiazepine-induced central nervous system depression.
• Exercise extreme caution using flumazenil; carries substantial risk unmasking intractable seizures particularly with co-ingested pro-convulsant drugs or underlying seizure disorder.
• Provide rapid diagnostic trial intravenous atropine 0.05 to 0.1 mg/kg for profound cholinergic signs highly suspicious for organophosphate pesticide poisoning.
• Reverse life-threatening muscarinic symptoms including severe bradycardia and bronchorrhea using atropine.