Methemoglobinemia: Living with Dormant Devil.

Methemoglobin is an oxidized form of hemoglobin. NADH methemoglobin reductase deficiency or inactivity is the cause of methemoglobin. Excessive production, resulting in accumulation, causes methemoglobinemia. It can be congenital or acquired. We present a case of dormant congenital methemoglobinemia detected accidentally on preoperative assessment, due to low oxygen saturation even at F1O2-1.0 associated with central cyanosis. The patient had 27.7 % methemoglobin, living his life without any complications. The patient was operated upon successfully for tympanoplasty and mastoidectomy under local anesthesia by taking proper precautions.