Severe methemoglobinemia due to ingestion of toxicants.

Abstract

BACKGROUND:

Toxin-induced methemoglobinemia is seen in poisoning with oxidizing agents. We report the clinical features and outcome of patients admitted with severe methemoglobinemia due to intentional ingestion of toxicants.

METHODS:

In this observational case series, patients admitted with toxin-induced methemoglobinemia between September 2011 and January 2014 were identified from the institutional poisoning database. Clinical profile and outcome of patients with methemoglobin concentration greater than or equal to 49% is reported.

RESULTS:

Of the 824 patients admitted with poisoning, 5 patients with methemoglobin concentration greater than or equal to 49% were included. The implicated compounds were nitrobenzene, benzoylphenylurea, flubendamide and Rishab(TM). One patient refused to name the compound. All patients were managed in the intensive care unit. Altered sensorium [Glasgow coma scale (GCS) < 10] was common (80%); 2 patients presented with a GCS greater than 4. All patients manifested cyanosis, low oxygen saturation and chocolate-brown-colored blood despite supplemental oxygen therapy. The median methemoglobin concentration was 64.7% (range 49.8-91.6%); 2 patients had methemoglobin concentration greater than 70%. One patient needed inotropes. Four patients required mechanical ventilation for 4-14 days. All patients were treated with methylene blue; 4 received more than one dose. Three patients also received intravenous ascorbic acid 500 mg, once daily, for 3 days. Following treatment, there was evidence of haemolysis in all patients; 2 required blood transfusion. All patients survived.

CONCLUSION:

Patients with severe toxin-induced methemoglobinemia present with altered sensorium and cyanosis and may require ventilatory support and inotropes. Though methemoglobin concentrations greater than 70% are considered fatal, aggressive management with methylene blue and supportive therapy can lead to survival.

• Authors: S R D'sa, P Victor, M Jagannati, T I Sudarsan, R A B Carey, J V Peter
• Journal: Clinical toxicology (Philadelphia, Pa.) (Clin Toxicol (Phila)) 2014 Sep-Oct Vol. 52 Issue 8 Pg. 897-900 ISSN: 1556-9519 [Electronic] England
• PMID: 25116418 (Publication Type: Journal Article, Observational Study)

Chemical References

• Nitrobenzenes
• Poisons
• Methemoglobin
• nitrobenzene
• Methylene Blue

Topics

• Administration, Oral
• Adult
• Cyanosis (chemically induced, diagnosis, drug therapy)
• Humans
• Methemoglobin (metabolism)
• Methemoglobinemia (chemically induced, diagnosis, drug therapy)
• Methylene Blue (therapeutic use)
• Middle Aged
• Nitrobenzenes (toxicity)
• Poisons (toxicity)
• Young Adult