What is the toxicology protocol for managing naphthalene ball ingestion in pediatric patients?

Management of Naphthalene Ball Ingestion in Children

Naphthalene mothball ingestion in children requires immediate supportive care focused on preventing and treating hemolytic anemia, methemoglobinemia, and acute kidney injury, with no role for gastric decontamination due to aspiration risk.

Immediate Assessment and Stabilization

Establish airway patency and continuous cardiorespiratory monitoring as the first priority, assessing vital signs including oxygen saturation, heart rate, blood pressure, and respiratory status 1. Contact your regional poison control center immediately for expert guidance 1.

Critical Initial Actions:

• Do NOT induce emesis, perform gastric lavage, or administer activated charcoal due to high aspiration risk from naphthalene's low viscosity and high volatility 2
• Obtain immediate laboratory studies: complete blood count with reticulocyte count, methemoglobin level, comprehensive metabolic panel including BUN and creatinine, liver function tests, lactate dehydrogenase, haptoglobin, total and direct bilirubin, and urinalysis 3, 4
• Screen for glucose-6-phosphate dehydrogenase (G6PD) deficiency, as these patients are at dramatically higher risk for severe hemolysis 3

Monitoring and Observation Period

All children, even if asymptomatic at presentation, require observation for at least 6 hours after exposure 2. However, symptoms can develop 2-3 days post-ingestion, so parental education about delayed manifestations is critical 5.

Key Clinical Manifestations to Monitor:

• Hemolytic anemia: fever, abdominal pain, hemoglobinuria (dark/tea-colored urine), jaundice, pallor 3, 2, 4
• Methemoglobinemia: cyanosis unresponsive to oxygen, chocolate-brown blood 2, 5
• Acute kidney injury: decreased urine output, hematuria, elevated creatinine 4, 6
• Central nervous system effects: confusion, lethargy, seizures (less common than with camphor) 2

Treatment of Hemolytic Anemia

Packed red blood cell transfusion is indicated for symptomatic anemia or hemoglobin levels causing hemodynamic compromise 3, 4. The severity of hemolysis can be profound, particularly in G6PD-deficient patients 3.

Supportive Measures:

• Aggressive intravenous hydration to maintain urine output and prevent acute tubular necrosis from hemoglobinuria 2, 4
• Alkalinization of urine (sodium bicarbonate) in the presence of hemoglobinuria to prevent hemoglobin precipitation in renal tubules 2
• Serial monitoring of hemoglobin, reticulocyte count, and markers of hemolysis (LDH, haptoglobin, bilirubin) 3

Treatment of Methemoglobinemia

Methylene blue (1-2 mg/kg IV over 5 minutes) is indicated only if methemoglobin levels exceed 20% with symptoms or exceed 30% regardless of symptoms 1. Do not exceed a cumulative dose of 7 mg/kg to avoid methylene blue-induced hemolysis 1.

Critical Contraindications and Alternatives:

• Methylene blue is absolutely contraindicated in G6PD deficiency as it will worsen hemolysis 1
• For G6PD-deficient patients with severe methemoglobinemia, consider exchange transfusion or plasmapheresis 5
• Ascorbic acid (vitamin C) and N-acetylcysteine have been used as adjunctive therapies, though evidence is limited 5

Management of Acute Kidney Injury

Renal replacement therapy (hemodialysis) is indicated for severe AKI with oliguria/anuria, severe electrolyte disturbances, or volume overload unresponsive to medical management 4, 5.

Renal Protection Strategies:

• Maintain adequate hydration with crystalloid fluids to ensure urine output >1 mL/kg/hour 4
• Monitor fluid and electrolyte balance closely, particularly potassium in the setting of hemolysis 2
• Serial creatinine and urine output monitoring for early detection of AKI 4, 6

Advanced Interventions for Severe Cases

Plasmapheresis should be considered for refractory severe methemoglobinemia or massive hemolysis not responding to conventional therapy 5. This case report demonstrated improvement after two sessions of plasmapheresis when methylene blue and supportive care failed 5.

Disposition and Follow-Up

• Admit to pediatric intensive care unit if any of the following are present: symptomatic anemia requiring transfusion, methemoglobin >20%, AKI, or significant hemolysis 3, 4
• Asymptomatic patients with normal initial laboratories may be observed for 6 hours and discharged with strict return precautions 2
• Provide detailed discharge instructions emphasizing that symptoms can develop 2-3 days post-ingestion, requiring immediate return for dark urine, decreased urine output, jaundice, or pallor 5

Common Pitfalls to Avoid

• Do not attempt gastric decontamination - this increases aspiration risk without benefit given naphthalene's poor GI absorption 2
• Do not administer methylene blue without checking G6PD status - this can be catastrophic in deficient patients 1, 3
• Do not discharge asymptomatic patients without adequate observation period - delayed presentations are common 2, 5
• Do not underestimate fluid requirements - aggressive hydration is essential to prevent AKI from hemoglobinuria 2, 4

Prevention Counseling

Educate families about safe storage of mothballs away from children's reach, avoiding storage in food/beverage containers, and considering safer alternatives to naphthalene-containing products 2.