Etymed
methemoglobinemia
Definition
A blood condition characterized by the presence of methemoglobin in the blood, which cannot carry oxygen effectively
Clinical context
A 35-year-old patient presents to the emergency department with cyanosis and shortness of breath after exposure to nitrate-contaminated well water. Arterial blood gas shows normal oxygen saturation despite adequate oxygenation. Methemoglobin levels are elevated on co-oximetry. The patient responds dramatically to methylene blue therapy. This condition results from the conversion of iron in hemoglobin from the ferrous to ferric state, rendering the hemoglobin incapable of oxygen transport.
Mnemonic
Methemoglobin - 'Meth' is for 'Methemoglobin' - think 'Meth' (drug) causing 'Methemoglobin' poisoning, or remember 'Meth' as the 'M' in 'Methemoglobin' that's 'Messed up' and can't carry oxygen properly
These morphemes also unlock…
- met- — beyond; changed
- hem/o — blood
- globin — globular protein (from globus, ball)
- -emia — blood condition