What is the recommended management for a patient with suspected naphthalene ingestion presenting within one hour?

Management of Naphthalene Ingestion

Immediate Stabilization and Supportive Care

For naphthalene ingestion presenting within one hour, focus on aggressive supportive care with airway protection, monitoring for hemolysis and methemoglobinemia, and avoid gastric decontamination due to aspiration risk. 1, 2

Initial Assessment and Monitoring

• Do NOT induce emesis, perform gastric lavage, or administer activated charcoal due to the risk of aspiration pneumonitis from naphthalene's volatile nature 1
• Establish continuous monitoring including vital signs, oxygen saturation, and cardiac telemetry 2
• Obtain immediate laboratory workup including:
  • Complete blood count with peripheral smear to assess for hemolysis 3, 2
  • Methemoglobin level (toxicity typically manifests as acute hemolysis and methemoglobinemia) 1, 2
  • Comprehensive metabolic panel including renal function (naphthalene can cause acute kidney injury from pigment nephropathy) 1, 4
  • Glucose-6-phosphate dehydrogenase (G6PD) screening, as toxicity is markedly worse in deficient patients 3, 2
  • Urinalysis for hemoglobinuria 1, 4

Airway and Respiratory Management

• Secure airway if respiratory depression develops, as naphthalene can cause CNS depression 2
• Provide supplemental oxygen for hypoxemia 1
• Monitor closely for aspiration pneumonitis if vomiting occurred during or after ingestion 1

Management of Specific Complications

Methemoglobinemia Treatment

• Administer intravenous methylene blue (1-2 mg/kg over 5 minutes) for severe methemoglobinemia >20-30% 2
• Methylene blue is highly effective but absolutely contraindicated in severe G6PD deficiency as it can worsen hemolysis 5, 2
• For patients with G6PD deficiency or when methylene blue is contraindicated, consider:
  • Ascorbic acid (vitamin C), though its effect is slow and requires multiple doses over several hours 5, 3
  • Exchange transfusion for refractory cases 5
  • Hyperbaric oxygen therapy, though reduction of methemoglobinemia may be delayed up to several hours 5

Hemolytic Anemia Management

• Transfuse packed red blood cells for severe anemia from acute intravascular hemolysis 3, 6, 4
• Hemolysis can persist for 5 days or longer post-ingestion, requiring serial monitoring 6
• Provide aggressive intravenous hydration to maintain urine output and prevent pigment nephropathy 1, 4
• Administer intravenous sodium bicarbonate to alkalinize urine in the presence of hemoglobinuria to prevent acute kidney injury 1

Renal Protection

• Monitor fluid and electrolyte balance closely 1
• Consider renal replacement therapy (continuous venovenous hemofiltration) for severe cases with acute kidney injury 6

Adjunctive Therapies

• N-acetylcysteine may be administered empirically, though evidence is limited to case reports 3, 6
• Note that N-acetylcysteine did not reduce methemoglobinemia in controlled studies, but may provide antioxidant support 5

Observation and Disposition

• Observe all patients for at least 6-8 hours after exposure, even if asymptomatic 1
• Patients with any signs of hemolysis, methemoglobinemia, or respiratory symptoms require hospital admission 2
• ICU admission is indicated for:
  • Severe hemolysis requiring transfusion 6, 4
  • Methemoglobinemia requiring methylene blue 2, 6
  • Respiratory depression or acute kidney injury 1, 2
• Psychiatric evaluation is mandatory before discharge for intentional ingestions 6

Critical Pitfalls to Avoid

• Never perform gastric lavage or induce emesis - this increases aspiration risk significantly 1
• Do not administer methylene blue to patients with G6PD deficiency - it will worsen hemolysis and can be fatal 5, 2
• Do not discharge patients early - hemolysis and methemoglobinemia can develop or worsen over 2-5 days post-ingestion 6
• Do not assume low toxicity based on initial presentation - naphthalene toxicity typically manifests abruptly with high morbidity and mortality, especially in G6PD-deficient patients 2