SHM Converge Scientific Abstract ePoster Gallery-Beyond the Wardrobe: Uncovering the Risks of Mothball Ingestion

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This case describes an 88-year-old man with dementia, chronic kidney disease, and hypertension who presented with 3 days of nausea, vomiting, diarrhea, and altered mental status. Despite 100% oxygen, his pulse oximetry remained severely low at 60%, while arterial blood gas showed a PaO2 of 306, creating a marked SpO2–PaO2 gap. Additional findings included leukocytosis, elevated lactate, chocolate-brown blood, and inability to obtain a methemoglobin level due to hemolysis. After further discussion, family reported possible mothball ingestion, leading to suspected naphthalene toxicity causing methemoglobinemia and hemolysis.<br /><br />He was treated with two doses of methylene blue, with only mild improvement. Over the next day, labs suggested hemolytic anemia with falling hemoglobin, rising LDH, and low haptoglobin. A G6PD level was normal, though it may have been falsely reassuring. Because symptoms and oxygenation abnormalities persisted, he underwent red blood cell exchange transfusion, which led to clinical improvement and normalization of oxygen saturation and hemolysis markers.<br /><br />The report emphasizes that naphthalene, a common mothball ingredient, can cause serious toxicity even after ingestion of a single mothball. Typical manifestations include gastrointestinal symptoms, lethargy, dyspnea, cyanosis, dark urine, renal or liver injury, methemoglobinemia, and intravascular hemolysis. Treatment is primarily supportive, with methylene blue as first-line therapy for methemoglobinemia, ascorbic acid if methylene blue is contraindicated, and exchange transfusion for refractory cases. The authors also stress the importance of considering G6PD deficiency, since methylene blue can worsen hemolysis in deficient patients. Prompt history-taking and recognition of the SpO2–PaO2 gap were key to diagnosis.

Asset Subtitle

Jennifer J. McEntee

Meta Tag

Author List Jennifer J. McEntee, Rachel Wietfeld

Category Clinical Vignettes

Concept Naphthalene Toxicity

Concept Methemoglobinemia

Concept Hemolysis

Concept SpO2-PaO2 Gap

Concept Methylene Blue

Distinguished Non-Finalist

Presenter Organization Unc

Presenting Author Jennifer J. McEntee

Track Adult

Keywords

naphthalene toxicity

methemoglobinemia

hemolysis

mothball ingestion

SpO2-PaO2 gap

methylene blue

exchange transfusion

G6PD deficiency

chocolate-brown blood

oxygen saturation

Naphthalene Toxicity

Methemoglobinemia

Hemolysis

SpO2-PaO2 Gap

Methylene Blue