# A Cyanotic Dilemma: Nitrobenzene Poisoning—A Case Report

**Authors:** Janmejay Kumar Singh, Adrian Villaroman, Jaehoon Kim, Ghazal Majidi, Diana Stefanie Rojas Torres, Mrinal Bhandari, Fazeela Bibi, Khalil E. L. Abdi, Ujjwal Dutta, Sojitra Vani

PMC · DOI: 10.1002/ccr3.71329 · 2025-10-30

## TL;DR

A 19-year-old woman's suicide attempt with nitrobenzene caused severe cyanosis and hypoxia, successfully treated with methylene blue.

## Contribution

This case report highlights the rare but life-threatening condition of methemoglobinemia due to nitrobenzene poisoning and emphasizes early treatment and mental health support.

## Key findings

- Nitrobenzene poisoning led to methemoglobinemia confirmed by ABG analysis showing 37.5% methemoglobin.
- Intravenous methylene blue and vitamin C improved clinical outcomes in the patient.
- The case underscores the importance of timely diagnosis and psychiatric evaluation in intentional poisoning cases.

## Abstract

Acquired methemoglobinemia can rarely be caused by acute nitrobenzene poisoning, presenting as oxygen‐unresponsive, life‐threatening hypoxia. We discuss a case of a 19‐year‐old female who attempted suicide through intentional nitrobenzene poisoning. She presented to the emergency department with progressive cyanosis, severe abdominal pain, and dyspnea. Her symptoms were suggestive of methemoglobinemia, which was confirmed through arterial blood gas (ABG) analysis, revealing a methemoglobin level of 37.5%. Treatment included intravenous methylene blue, vitamin C, and supportive care, leading to clinical improvement. This case highlights the critical need for early recognition and timely administration of methylene blue, particularly in resource‐limited settings where delayed diagnosis can increase morbidity. It also signifies the importance of integrating psychiatric evaluation and mental health support in cases of intentional poisoning to prevent recurrence.

## Linked entities

- **Chemicals:** nitrobenzene (PubChem CID 7416), methylene blue (PubChem CID 4139), vitamin C (PubChem CID 54670067)
- **Diseases:** methemoglobinemia (MONDO:0001117)

## Full-text entities

- **Genes:** HBG2 (hemoglobin subunit gamma 2) [NCBI Gene 3048] {aka HBG-T1, TNCY}
- **Diseases:** cyanosis (MESH:D003490), dyspnea (MESH:D004417), Poisoning (MESH:D011041), psychiatric (MESH:D001523), methemoglobinemia (MESH:D008708), abdominal pain (MESH:D015746), hypoxia (MESH:D000860)
- **Chemicals:** Nitrobenzene (MESH:C036077), oxygen (MESH:D010100), methylene blue (MESH:D008751), vitamin C (MESH:D001205)

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Source: https://tomesphere.com/paper/PMC12575183