methemoglobinemia
Pronunciation: meth-ee-moh-GLOB-ih-NEE-mee-ah
A condition in which an abnormally high proportion of haemoglobin is oxidised to methemoglobin, impairing oxygen transport; a known adverse effect of benzocaine overuse in dental and anesthesia contexts.
Full Definition
Methemoglobinemia occurs when iron in haemoglobin is oxidised from the ferrous (Fe²⁺) to the ferric (Fe³⁺) state, producing methemoglobin, which cannot bind or transport oxygen. In dental anesthesiology, it is most commonly associated with excessive use of benzocaine topical anesthetic, particularly in infants and young children. Clinical signs include cyanosis disproportionate to pulse oximetry readings, because standard pulse oximetry (SpO₂) may falsely read ~85% regardless of true methemoglobin levels. Editors should flag the British spelling variant 'methaemoglobinaemia' and ensure consistency within a document. The condition is treated with methylene blue and is a reportable adverse event in office-based anesthesia contexts.
Usage
Usage note: Use American spelling 'methemoglobinemia' in US publications and British spelling 'methaemoglobinaemia' in UK/Australian publications; do not mix within a document.
In Context
- "The case report described an infant who developed methemoglobinemia following application of excessive benzocaine gel to the oral mucosa before a dental procedure." — Paediatric dentistry case report
- "The editor flagged the inconsistent use of 'methemoglobinemia' and 'methaemoglobinaemia' within the same article and queried the author for their preferred variant." — Copyediting a clinical anesthesia journal