Case challenge · Emergency / Toxicology / Critical care · teaching

Methemoglobinemia — Management Pathway · case challenge

Given a case, work through the care pathway step by step; the tool checks each choice and scores you. Decisions and basis are taken from this site's reviewed care pathways.

← View the full flowchartBased on StatPearls / WikEM

Case #1Emergency / Toxicology / Critical care

📋 Case data

Antidote needed?Symptomatic / MetHb >20–30%

Data is taken from this pathway's reviewed node text. Work through the pathway step by step.

Step 1 / 1 · Antidote needed?

Cyanosis + saturation gap — is an antidote needed?

💡 Iron Fe2+ → Fe3+ cannot carry oxygen (oxidizers: benzocaine/prilocaine/lidocaine, nitrites, dapsone, nitroglycerin, etc.). Cyanosis not relieved by oxygen + chocolate-brown blood + a saturation gap (pulse oximetry ~85% while ABG PaO2 is normal/high, gap >5%). Pulse oximetry is unreliable — confirm with blood-gas co-oximetry (sulfhemoglobin is misread as methemoglobin). Severity by absolute amount (Hb × %MetHb).

For teaching. Decisions and their basis are taken from this site's reviewed care pathways; for licensed clinicians/trainees, this does not replace clinical judgment or local protocols.