Methemoglobin is formed upon iron oxidation of the heme molecule from ferrous (Fe2+) to its ferric (Fe3+) state. Normal methemoglobin levels in the body vary between 1-2% of the total hemoglobin. Cause of methemoglobinemia can be inherited or acquired. Inherited causes include an enzymatic deficiency in the enzyme cytochrome b5 reductase where as acquired causes are most commonly from routinely used medications. Herein, we present to you a case of methemoglobinemia after Cetacaine (a benzocaine based topical anesthetic) utilization during a transesophageal echocardiography. Some of the other common potential inciting agents are also discussed here along with an overview of treatment strategies.
