Problems for Discussion - 3 - Methaemoglobinaemia

• Understand the mechanisms of methaemoglobinaemia
• Understand the basis of treatment with methylene blue
• Understand the issues underlying treatment failure

You are working in a rural hospital in Asia. A patient presents following ingestion of a herbicide called Propanil. Propanil is known to cause methaemoglobinaemia. Your patient is very blue and unconscious. You have no pathology.

1. What things would you include in your clinical assessment?
2. You have 100 mg of methylene blue that your mother prophetically packed with your toothpaste and antimalarials. You give this; however, the patient is still blue but wakes and speaks with you (in a language you don’t understand). Then 1 hour later he deteriorates. How would you interpret this sequence of events?
3. You have searched your bag and there are no more blue things. What will you do now?

1. What other chemicals, including pharmaceuticals can cause methaemoglobinaemia?
2. Who is particularly at risk of methaemoglobinaemia and why?