What is the treatment approach for a patient with a history of naphthalene ball ingestion, potentially presenting with symptoms such as nausea, vomiting, abdominal pain, and respiratory distress?

Naphthalene Ball Ingestion: Treatment Approach

For naphthalene mothball ingestion, immediately provide supportive care with aggressive IV hydration, monitor for hemolysis and methemoglobinemia, and administer methylene blue (1-2 mg/kg IV) if methemoglobin levels exceed 30%, along with ascorbic acid and N-acetylcysteine as adjunctive therapy.

Initial Assessment and Stabilization

• Follow Advanced Trauma Life Support (ATLS) principles with simultaneous evaluation for toxin-specific effects, prioritizing airway, breathing, and circulation 1
• Assess for traumatic cervical injury before any airway manipulation 1
• Treat the patient as having a "full stomach" requiring rapid sequence induction with Sellick maneuver if intubation is needed 1
• Obtain immediate laboratory studies: complete blood count with reticulocyte count, methemoglobin level, total and indirect bilirubin, lactate dehydrogenase, haptoglobin, blood urea nitrogen, creatinine, and urinalysis 2, 3

Specific Antidotal and Supportive Therapy

Methemoglobinemia Management

• Administer methylene blue 1-2 mg/kg IV immediately if methemoglobin levels exceed 30% or if symptomatic with lower levels 4, 2
• Use ascorbic acid as alternative or adjunctive therapy when methylene blue is unavailable or contraindicated, though it acts more slowly 4, 3, 5

Hemolysis Management

• Provide aggressive IV fluid resuscitation to maintain adequate urine output and prevent acute kidney injury from hemoglobinuria 2, 6
• Transfuse packed red blood cells for severe anemia (hemoglobin <7 g/dL or symptomatic anemia) 2, 3, 6
• Administer N-acetylcysteine as an antioxidant to reduce oxidative stress 2, 3, 5
• Consider plasmapheresis for refractory cases with persistent severe hemolysis despite standard therapy 2

Renal Protection

• Ensure adequate hydration with judicious fluid administration to prevent myoglobinuric renal failure 1
• Monitor serum creatinine kinase and potassium levels to detect rhabdomyolysis 1
• Implement urine alkalinization if myoglobinuria develops 1
• Initiate hemodialysis for acute kidney injury with oliguria or anuria 2, 6

Critical Monitoring Parameters

• Continuous pulse oximetry (note: persistent readings of 84-85% despite oxygen supplementation are characteristic of methemoglobinemia) 3
• Serial hemoglobin, haptoglobin, and bilirubin levels every 6-12 hours during acute phase 2, 7, 3
• Urine output and color (dark brown urine indicates hemoglobinuria) 3, 6
• Renal function tests daily 2, 6
• Methemoglobin levels every 4-6 hours until normalized 2, 3

High-Risk Populations

• Screen for glucose-6-phosphate dehydrogenase (G6PD) deficiency in all patients, as these individuals are at significantly higher risk for severe hemolytic crisis 7, 5
• Children and patients with underlying hemolytic disorders require more aggressive monitoring and earlier intervention 7, 6, 5

Common Pitfalls and Caveats

• Symptoms typically present 48-96 hours after exposure, not immediately, so delayed presentations are common 3, 6
• Abdominal pain with nausea and vomiting can mimic surgical abdomen but is usually due to toxicity rather than visceral perforation 1
• Do not rely solely on pulse oximetry for oxygenation assessment, as methemoglobinemia causes falsely low readings 3
• Avoid methylene blue in patients with G6PD deficiency as it can paradoxically worsen hemolysis; use ascorbic acid instead 5
• Even small ingestions (one to two mothballs) can cause severe toxicity in susceptible individuals 7, 5

Expected Clinical Course

• Clinical manifestations include fever, tachycardia, abdominal pain, vomiting, dark urine, and decreased urine output 3, 6
• Laboratory findings show hemolytic anemia with elevated reticulocyte count, indirect hyperbilirubinemia, elevated lactate dehydrogenase, low haptoglobin, and variable methemoglobinemia 2, 7, 3
• With appropriate treatment, most patients show improvement within 48-72 hours and can be discharged after 7-15 days 2, 3