Sakthi Saravanan Naren Karthik, Manikandan Kanishka
Coimbatore Medical College and Hospital, Coimbatore, India
Department of Emergency Medicine, PSG Institute of Medical Sciences and Research, Coimbatore, India.
BMJ Case Rep. 2025 Apr 24;18(4):e264618. doi: 10.1136/bcr-2024-264618.
Methaemoglobin is an altered state of haemoglobin wherein the iron moiety of haemoglobin is oxidised from its ferrous (Fe2+) to ferric (Fe3+) form. Methaemoglobinaemia is a condition characterised by increased methaemoglobin concentration in the blood that is greater than 1%. It is a potentially life-threatening condition as methaemoglobin hinders the delivery of oxygen to tissues, leading to hypoxia and tissue damage. Here we report a case of methaemoglobinaemia induced by self-poisoning with a plant growth promoter in India, which contained only organic substances and was free of any toxic substance. Prompt clinical suspicion and evaluation are critical to identify acquired methaemoglobinaemia because the condition is rare but potentially life-threatening. To summarise, methaemoglobinaemia is to be suspected with low oxygen saturation that does not improve on oxygen supplementation, disparity between spO2 and pO2 and chocolate brown coloured blood. It is treated with methylene blue, which reduces methaemoglobin to haemoglobin.
高铁血红蛋白是血红蛋白的一种改变状态，其中血红蛋白的铁部分从亚铁（Fe2+）氧化为铁（Fe3+）形式。高铁血红蛋白血症是一种以血液中高铁血红蛋白浓度升高（大于1%）为特征的病症。这是一种潜在的危及生命的病症，因为高铁血红蛋白会阻碍氧气向组织的输送，导致缺氧和组织损伤。在此，我们报告一例在印度因自服一种植物生长促进剂而诱发的高铁血红蛋白血症病例，该植物生长促进剂仅含有有机物质，不含任何有毒物质。及时的临床怀疑和评估对于识别后天性高铁血红蛋白血症至关重要，因为这种病症罕见但可能危及生命。总之，当出现吸氧后氧饱和度仍低、脉搏血氧饱和度（spO2）与动脉血氧分压（pO2）不一致以及血液呈巧克力棕色时，应怀疑高铁血红蛋白血症。该病用亚甲蓝治疗，亚甲蓝可将高铁血红蛋白还原为血红蛋白。
