What is the recommended emergency evaluation and treatment for a child who has ingested a naphthalene mothball, including considerations for possible G6PD deficiency?

Naphthalene Ball Ingestion in a Child

Immediately assess for hemolysis and methemoglobinemia, provide aggressive supportive care with IV fluids and blood transfusions as needed, avoid methylene blue until G6PD deficiency is ruled out, and use ascorbic acid or N-acetylcysteine for methemoglobinemia if G6PD status is unknown or deficient.

Emergency Evaluation

Initial Clinical Assessment

• Check vital signs for tachycardia, respiratory distress, and signs of shock, as naphthalene toxicity can cause acute multi-organ dysfunction 1, 2
• Examine for jaundice, pallor, dark urine, and abdominal pain, which indicate acute hemolysis 1, 3, 4
• Obtain detailed history about timing of ingestion (symptoms typically appear 1-4 days post-exposure) and quantity of mothball consumed 1, 3, 4

Critical Laboratory Studies

• Draw complete blood count with reticulocyte count, peripheral smear, lactate dehydrogenase, total and indirect bilirubin, haptoglobin, blood urea nitrogen, and creatinine to assess for hemolysis and acute kidney injury 1, 2, 3
• Measure methemoglobin level immediately, as naphthalene causes both hemolysis and methemoglobinemia 1, 4, 5
• Do NOT perform G6PD testing during the acute hemolytic episode, as reticulocytes and young red cells contain near-normal enzyme levels that will mask true deficiency 6
• Check liver function tests and creatine kinase, as naphthalene can cause hepatic dysfunction and rhabdomyolysis 1, 2

Acute Management

Supportive Care

• Administer aggressive IV fluid resuscitation to maintain renal perfusion and prevent acute kidney injury from hemoglobinuria 1, 2
• Transfuse packed red blood cells for severe anemia (hemoglobin typically drops precipitously in naphthalene-induced hemolysis) 1, 3
• Prepare for mechanical ventilation and intensive care unit admission in severe cases with multi-organ dysfunction 1
• Consider hemodialysis if acute kidney injury develops with oliguria or anuria 2

Methemoglobinemia Treatment—Critical Decision Point

• Never use methylene blue if G6PD deficiency cannot be ruled out, as it will precipitate severe hemolysis and paradoxically worsen methemoglobinemia 6, 7, 8, 5
• Use ascorbic acid (0.5-10 g IV) as first-line therapy for methemoglobinemia when G6PD status is unknown or deficiency is suspected 6, 1, 4
• Administer N-acetylcysteine as an alternative or adjunctive therapy, particularly if hepatic dysfunction is present 1, 4
• Consider exchange transfusion for severe methemoglobinemia (>20-30%) or refractory hemolysis when methylene blue cannot be used 6, 5

Specific Antidotes and Adjuncts

• N-acetylcysteine should be given empirically in severe cases, as it provides antioxidant support and may mitigate organ damage 1, 4
• Monitor for rebound methemoglobinemia requiring repeat ascorbic acid dosing every 6-8 hours for up to 2-3 days 6

G6PD Deficiency Considerations

Why G6PD Status Matters

• Naphthalene toxicity is dramatically worse in G6PD-deficient children, causing more severe hemolysis, higher mortality, and multi-organ failure 1, 3, 4, 5
• G6PD-deficient patients cannot generate sufficient NADPH to reduce oxidant stress from naphthalene or to convert methylene blue to its active form 6
• The Mediterranean variant causes life-threatening hemolysis, while the African variant produces milder disease 6, 8

Delayed G6PD Testing Protocol

• Wait at least 50-120 days after the acute hemolytic episode before performing quantitative G6PD testing to avoid false-negative results 6
• Screen all children of Mediterranean, African, Indian, or Southeast Asian descent who present with naphthalene ingestion, as these populations have higher G6PD deficiency prevalence 6, 8
• Test first-degree relatives if the child is confirmed G6PD-deficient 6

Common Pitfalls to Avoid

• Never give methylene blue empirically without knowing G6PD status—this is the most dangerous error in naphthalene poisoning management 6, 7, 5
• Never rely on absence of symptoms in the first 24 hours to rule out toxicity, as hemolysis typically develops 1-4 days post-ingestion 1, 3, 4
• Never perform G6PD testing during acute hemolysis, as it will produce falsely normal results and lead to incorrect future medication decisions 6
• Never underestimate the severity based on the small size of a mothball—even a single mothball can cause life-threatening toxicity in susceptible children 1, 3

Monitoring and Disposition

• Admit all symptomatic children to the ICU for continuous monitoring of hemoglobin, methemoglobin, renal function, and urine output 1, 2
• Expect a 2-week recovery period in severe cases with multi-organ involvement 1
• Arrange outpatient G6PD testing 3-4 months after discharge to guide future medication safety 1, 3, 4
• Educate families about household mothball hazards and the need to secure these products away from children 3