Bupivacaine-Induced Methemoglobinemia in the Setting of Sepsis

Introduction Methemoglobinemia is a rare disorder that occurs when iron in hemoglobin oxidizes from ferrous (Fe2+) to ferric (Fe3+) state which is unable to bind to oxygen, causing hypoxia, organ damage and even death [1]. It is divided into hereditary and acquired. The latter can be caused by certain drug ingestion, which will be the focus of our case report [2]. Case Presentation A 5-year-old male patient with suspected post-traumatic osteomyelitis and Ewing sarcoma was admitted to the hospital with febrile fever, vomiting and left thigh pain. On observation, ulcers were found on the mucous membrane of the inner cheek; as a result, topical bupivacaine was used. Laboratory tests revealed increased C-reactive protein, procalcitonin, ferritin, abnormal coagulation, liver damage and metabolic acidosis, as well as ketonuria and hematuria; as a result, sepsis was diagnosed. Even though antibacterial treatment was administered, on the second day of hospitalization, the boy’s condition worsened – SaO2 decreased to 83%, skin was cyanotic, tachycardia and hypertension were present. Oxygen therapy had no effect, so the patient was intubated and artificial lung ventilation with 100% oxygen was started, but saturation remained low. After performing arterial blood gas analysis, methemoglobinemia (MetHb 42%) was determined as the cause of the condition. Vitamin C and methylene blue were given and after an hour, SaO2 increased to 98%, extubation was performed, MetHb decreased to 1.3%. The cause of methemoglobinemia is suspected to be a reaction to a local anesthetic bupivacaine, which was intended to treat oral mucosal stomatitis. Discussion An increasing amount of data points to a connection between sepsis and methemoglobinemia. During sepsis, as a response to proinflammatory cytokines endothelial cells release copious amounts of nitric oxide, which reacts with hemoglobin to create methemoglobin. Consequently, patients with sepsis are more likely to have higher circulating MetHb as opposed to healthy peers [3]. Conclusions Methemoglobinemia is a life-threatening condition that can be caused by medications widely used in clinical settings. Hypoxia brought on by this disorder has the potential to become fatal rapidly. That is why it is vital to suspect, diagnose and treat patients as fast as possible [4].