Diagnosis and management of nitrobenzene poisoning in a low-resource setting: A case report

BACKGROUND: and Importance: Nitrobenzenes are aromatic oxidizing nitrate compounds, acute ingestion of which can cause methemoglobinemia (metHb) that impairs oxygen transport. Clinical presentation ranges from cyanosis to asphyxia depending on the level of methemoglobin in the blood. Lack of improvement of hypoxia despite administration of oxygen can also be a clue to the diagnosis. CASE PRESENTATION: A 23-year-old male with accidental ingestion of nitrobenzene presented with multiple episodes of vomiting, headache, and dyspnea. His venous blood was dark brown in color and oxygen saturation was not improving despite high-flow oxygen. He was managed with methylene blue and Vitamin C on this background with an appropriate history of nitrobenzene ingestion. DISCUSSION: Acute nitrobenzene poisoning results in methemoglobinemia which is diagnosed by Co-oximeter but in resource-limited settings, clinical findings such as no improvement in SpO(2) despite supplemental oxygen and chocolate brown appearance of blood aid in the diagnosis. Prompt treatment of methemoglobinemia with methylene blue along with Vitamin C has shown successful and effective outcomes. CONCLUSION: Diagnosis of acute nitrobenzene poisoning can be made with proper history, physical and bedside examinations in resource-limited settings even without the aid of a co-oximeter.