Methaemoglobinaemia – Clinical Case 1

A 22 year old female attends the ED with a twisted ankle after a “banging night out pulling some extreme moves”. She is otherwise fit and well and takes no medications. The triage nurse asks you to see the patient urgently as she “looks blue” and her sats are 89%. Her observations are otherwise normal. From the end of the bed she looks well with no respiratory distress, has a 15L NRB mask on and her sats are still 89%.

What initial investigation is going to be most useful in this patient?

Her MetHb level returns at 14%. What would be your management plan?

What would you suspect as a potential underlying cause and why is this important?