Exchange transfusion as a therapeutic modality for aniline dye-induced methaemoglobinaemia.

Methaemoglobinaemia and a Heinz-body haemolytic anaemia are uncommon but potentially treatable complications of aniline poisoning. Management of aniline poisoning is mainly removing the source of aniline exposure and management of methaemoglobinaemia. Management of methaemoglobinaemia is guided by blood methaemoglobin levels and patient symptoms. Blood methaemoglobin level <30% requires only supplemental oxygen while for methaemoglobin level >30%, intravenous methylene blue is the mainstay of treatment. All patients treated with methylene blue should be observed for delayed haemolysis, acute renal failure and cardiac complications. In patients with contraindication to methylene blue, exchange transfusion can be used while haemodialysis is reserved for complicated cases. We successfully managed 6 patients of methaemoglobinaemia due to aniline poisoning by methylene blue. Two of these patients who developed Heinz-body haemolytic anaemia with acute renal failure as a complication also required exchange transfusion.