Acute methaemoglobinaemia after massive nitrobenzene ingestion

Abstract

Flower-N is a flowering stimulant composition with 22% nitrobenzene. The main systemic effect associated with human exposure to nitrobenzene is methaemoglobinaemia. A 25-year-old female presented after 3 hours following ingestion of 100 ml of 22% Nitrobenzene (Flower-N). Her initial methaemoglobin (MetHb) was 81%; this responded to methylene blue. However, she developed recurrent methaemoglobinaemia on days 3 and 5 with haemolytic anaemia. The treatments that were provided were repeated methylene blue treatment and exchange transfusion. Nitrobenzene ingestion is a known cause of methaemoglobinaemia and haemolytic anaemia. The recurrence suggests a long half-life. The recurrent MetHb has clinical implications as patients may require repeated treatment. Massive nitrobenzene ingestion can cause haemolysis and recurrent methaemoglobinaemia.

Severe methemoglobinemia due to insecticide poisoning

“…MetHb levels of >70% are usually fatal, though survival has been reported with a MetHb level of 81%. [ 3 ] Our patient with a MetHb level of 91% had the highest reported level among methemoglobinemia survivors. The usual recommended dose of methylene blue is 7 mg/kg.…”

Therapeutic whole blood exchange in the management of methaemoglobinemia: Case series and systematic review of literature

“…Our search yielded 365 citations (Figure ), of which 25 fulfilled our inclusion criteria (27 subjects) . Studies that mentioned exchange transfusion in the management of methaemoglobinemia, but failed to provide the details, were also not included .…”

“…Median methaemoglobin concentration was 37.5% (range 3.7% to 81%), while in one subject the level was out of the detectable range . Methaemoglobin was measured using CO‐oximetry in the majority (n = 24, 75%), followed by absorption spectrophotometry (n = 4) . Of the 16 subjects in whom G‐6‐PD levels were reported, 6 (37.5%) were G‐6‐PD deficient …”

“…20 Methaemoglobin was measured using CO-oximetry in the majority (n = 24, 75%), followed by absorption spectrophotometry (n = 4). 7,18,24,26 Of the 16 subjects in whom G-6-PD levels were reported, 6 (37.5%) were G-6-PD deficient. 17,23,25,27,32…”