Thursday, October 20, 2011

Hurricane II

This is the second part of a two-part case; please see the prior post.

You confirm your diagnosis and begin treatment which is shown above (given as an IV bolus of 1-2mg/kg over 5 minutes). The patient does not get better after a few hours. In fact, he seems to get worse; he's more dyspneic. You decide to send another panel of labs, and when they come back, you note that the hemoglobin has dropped 3 points and the blood smear shows:

Challenge: What happened?

Image shown under Creative Commons Attribution Share-Alike License.


Anonymous said...

hemolysis 2/2 to methemoglobinemia--concern for G6PD or Pyruvate kinase deficiency

Craig Chen said...

nice!! i thought this was pretty tricky
Hurricane II

The treatment for methemoglobinemia is methylene blue to help reduce methemoglobin by an NADPH-dependent pathway. However, this is contraindicated if the patient has glucose-6-phosphate dehydrogenase deficiency since this pathway dependents on G6PD to generate NADPH. In this case, methylene blue can trigger hemolysis. The smear shows characteristic bite-like deformities on the left and denatured hemoglobin precipitates on the right.

Sources: UpToDate; Wikipedia.