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Chapters

0:00 Introduction
0:52 Types and Causes of Methemoglobinemia
2:46 Symptoms of Methemoglobinemia
3:24 Diagnosis of Methemoglobinemia
3:47 Treatment of Methemoglobinemia



Methemoglobinemia is a condition of elevated methemoglobin in the blood.[2] Symptoms may include headache, dizziness, shortness of breath, nausea, poor muscle coordination, and bluecolored skin (cyanosis).[2] Complications may include seizures and heart arrhythmias.[3]

Methemoglobinemia can be due to certain medications, chemicals, or food or it can be inherited from a person's parents.[2] Substances involved may include benzocaine, nitrates, or dapsone.[3] The underlying mechanism involves some of the iron in hemoglobin being converted from the ferrous [Fe2+] to the ferric [Fe3+] form.[3] The diagnosis is often suspected based on symptoms and a low blood oxygen that does not improve with oxygen therapy.[3] Diagnosis is confirmed by a blood gas.[3]

Treatment is generally with oxygen therapy and methylene blue.[3] Other treatments may include vitamin C, exchange transfusion, and hyperbaric oxygen therapy.[3] Outcomes are generally good with treatment.[3] Methemoglobinemia is relatively uncommon, with most cases being acquired rather than genetic.[3]