Overview
Definition:
Toxic ingestions in children refer to the accidental or intentional swallowing of potentially harmful substances, leading to adverse health effects
Iron, acetaminophen, and hydrocarbons are common culprits encountered in pediatric emergency settings, requiring prompt recognition and management.
Epidemiology:
Unintentional ingestions are most common in toddlers (1-3 years old), often involving household products
Iron supplements and acetaminophen-containing medications are frequent causes of severe poisoning
Hydrocarbon ingestions, typically from petroleum products, are also a significant concern.
Clinical Significance:
These ingestions can lead to severe morbidity and mortality if not managed promptly
Understanding the pathophysiology, clinical presentation, and specific antidotes or treatments is crucial for pediatric residents preparing for DNB and NEET SS examinations, as well as for providing optimal patient care.
Iron Ingestion
Stages:
Stage 1 (0-6 hours): Gastrointestinal irritation, vomiting, diarrhea, abdominal pain
Stage 2 (6-24 hours): Apparent recovery period with transient improvement
Stage 3 (12-48 hours): Metabolic acidosis, shock, hepatic dysfunction, seizures
Stage 4 (2-5 days): Hepatic failure
Stage 5 (2-5 weeks): Gastric outlet obstruction, esophageal strictures.
Diagnostic Criteria:
Clinical suspicion based on history of ingestion and serum iron level
A serum iron level > 300-350 mcg/dL is considered potentially toxic, and > 500 mcg/dL is highly toxic
Radiographs may reveal radiopaque tablets if present.
Management:
Decontamination: Activated charcoal may be less effective due to poor adsorption of iron
Gastric lavage may be considered for large, recent ingestions
Whole bowel irrigation with polyethylene glycol is indicated for radiopaque pills
Medical Management: IV fluids for hydration and shock
Deferoxamine mesylate is the specific antidote, administered IV, and indicated for significant toxicity (serum iron > 300-350 mcg/dL, metabolic acidosis, shock, obtundation)
Monitor for chelation side effects.
Complications:
Hepatic necrosis
Acute kidney injury
Hypoglycemia
Seizures
Gastric outlet obstruction
Esophageal strictures
Long-term neurological deficits.
Key Points:
The multi-stage nature of iron poisoning is critical
Deferoxamine is the antidote
Monitor iron levels and acid-base status closely.
Acetaminophen Ingestion
Stages:
Stage 1 (0-24 hours): Often asymptomatic or mild nausea/vomiting
Stage 2 (24-72 hours): Symptoms may temporarily subside, but hepatocellular damage begins
Stage 3 (72-96 hours): Peak hepatotoxicity with elevated transaminases, coagulopathy, jaundice, encephalopathy, hypoglycemia
Stage 4 (>96 hours): Recovery or progression to fulminant hepatic failure.
Diagnostic Criteria:
History of ingestion
Serum acetaminophen level plotted on a nomogram (e.g., Rumack-Matthew nomogram) at 4 hours post-ingestion
Consider activated charcoal for recent ingestions (<1-2 hours).
Management:
Decontamination: Activated charcoal within 1-2 hours of ingestion
Medical Management: N-acetylcysteine (NAC) is the antidote and is most effective when initiated within 8-10 hours of ingestion
Oral or IV routes are available
IV is preferred in severe overdose or if vomiting is persistent
Dosing is weight-based and follows specific protocols
Monitor liver function tests, coagulation profile, and glucose.
Complications:
Acute liver failure
Renal failure
Pancreatitis
Encephalopathy
Death.
Key Points:
The timing of NAC administration is paramount
Always check the acetaminophen level and plot it on the nomogram
Consider co-ingestion of other substances.
Hydrocarbon Ingestion
Definition:
Ingestion of volatile, lipophilic substances containing hydrocarbons, such as gasoline, kerosene, paint thinners, and furniture polish
These are common in young children due to easy access.
Clinical Presentation:
Most commonly presents with respiratory symptoms due to aspiration: coughing, choking, gagging, tachypnea, dyspnea, wheezing, cyanosis
May also have gastrointestinal symptoms like nausea, vomiting, abdominal pain
Neurological effects include lethargy, ataxia, and rarely seizures.
Diagnostic Approach:
History of exposure is key
Physical exam focuses on respiratory status and signs of aspiration
Chest X-ray may show pneumonitis, atelectasis, or pleural effusion, but can be normal early on
Gastric lavage and induced emesis are generally contraindicated due to risk of re-aspiration
Diligent airway management is crucial.
Management:
Supportive care is the cornerstone
Airway support: supplemental oxygen, mechanical ventilation if indicated
Close monitoring for respiratory distress
No specific antidote
Gastrointestinal decontamination is generally avoided
Antibiotics and steroids are usually not indicated unless there is a secondary bacterial infection or severe, persistent inflammation.
Complications:
Chemical pneumonitis
Acute respiratory distress syndrome (ARDS)
Secondary bacterial pneumonia
Bronchopleural fistula
Tracheoesophageal fistula.
Key Points:
The primary risk is aspiration pneumonitis
Avoid gastric lavage and emesis
Focus on supportive respiratory care
Chest X-ray findings may be delayed.
General Pediatric Toxicology
History Taking:
Crucial information includes: substance ingested, amount, time of ingestion, child's age and weight, any symptoms observed, co-ingestions
Always ask about potential suicidal intent in older children/adolescents.
Physical Examination:
A thorough head-to-toe examination is essential
Focus on: vital signs (temperature, heart rate, respiratory rate, blood pressure, oxygen saturation), mental status, airway patency, respiratory effort, skin (rashes, burns), abdomen (tenderness, distension), and neurological status (pupil size, reflexes, seizures).
Investigations:
Basic labs include: complete blood count (CBC), electrolytes, blood urea nitrogen (BUN), creatinine, glucose, liver function tests (LFTs), arterial blood gas (ABG) for acid-base status, and specific drug levels (e.g., acetaminophen, iron, salicylate)
Imaging: Chest X-ray for suspected hydrocarbon or other pulmonary involvement
Abdominal X-ray may detect radiopaque pills (e.g., iron).
Management Principles:
The ABCDE approach (Airway, Breathing, Circulation, Disability, Exposure) is fundamental
Decontamination (activated charcoal, gastric lavage, whole bowel irrigation) should be considered judiciously
Supportive care is paramount
Specific antidotes should be administered promptly when indicated
Consultation with a poison control center or toxicologist is highly recommended.
Key Points
Exam Focus:
Understand the stages of iron and acetaminophen poisoning
Know the specific antidotes and their indications/dosing
Recognize the primary danger of hydrocarbon ingestion (aspiration)
Emphasize supportive care in toxicology emergencies.
Clinical Pearls:
When in doubt, call poison control
Never assume a child will not ingest a toxic substance
Always consider co-ingestions, especially in intentional overdoses
The Rumack-Matthew nomogram is vital for acetaminophen management decisions.
Common Mistakes:
Delaying antidote administration for acetaminophen or iron poisoning
Performing gastric lavage or emesis in hydrocarbon ingestions
Underestimating the severity of asymptomatic presentations
Failing to consider co-ingestions.