Transcription
Cold Agglutinin Disease Mnemonic
In the previous video, we talked about cold agglutinin disease. Today, it's a nice mnemonic, but first, let's answer the vignette from the previous video. So, here we have a 56-year-old male who was shoveling snow in front of his house in the Midwest. If you don't know, the Midwest in the United States is very cold in the winter. When he suddenly developed cyanosis of fingertips and nose, he was taken to the emergency department. On physical exam, there is jaundice, splenomegaly, acrocyanosis. Review of his records revealed a history of mycoplasma infection as well as Waldenstrom macroglobulinemia. So, where is the problem here? Acrocyanosis after shoveling snow? Okay, could be maybe frostbite, just a reaction to the cold, but there is jaundice, splenomegaly, a history of mycoplasma infection, and Waldenstrom macroglobulinemia, all pointing to IgM. When you have splenomegaly and jaundice, this is hemolysis. Okay, so now we have hemolysis due to IgM and body exposure to cold. This is cold agglutinin disease or cold immune hemolytic anemia. What's the best diagnostic test? Bone marrow biopsy, indirect Coombs, or direct Coombs? And the answer is direct Coombs test.
Next, what's the next best step in management? Prednisone? No, we don't use steroids in the cold subtype. Keep the patient warm, or splenectomy? Splenectomy is contraindicated. So the answer is keep the patient warm. Let's go to the first question for us: why direct, why not indirect? The answer is the direct Coombs test will detect the antibody on the surface of the red blood cell; in this case, it's the IgM. Also, the direct Coombs test can detect the complement on the surface of the red blood cell. Indirect Coombs test, on the other hand, detects antibodies in the plasma or in the serum. Okay, so direct on the surface of the red blood cells, and indirect in the serum. We are looking for IgM or the complement on the red blood cell, so we use the direct Coombs test.
And now here's the mnemonic: You have grandpa shoveling snow, having acrocyanosis. So the nose is blue, fingertips blue, and toes blue; the ear is blue. Okay, now cold agglutinin disease is IgM. So we will draw in the nose, fingertips, and a mountain of snow. Cold ice cream is yummy, but a better mnemonic is the IgM is a pentamer, which looks like what? Snowflakes. So IgM is cold, IgM snowman, mycoplasma, mono, Waldenstrom macroglobulinemia, direct Coombs test. Please stay warm. He was given rituximab or cyclophosphamide. This spleen is mine because I want you to remember that splenectomy is contraindicated in cold agglutinin disease. Only do splenectomy in the warm subtype, not the cold. So the spleen is mine. Here is your nice snowman to remember cold agglutinin disease is due to exposure to cold weather. Poor grandpa. See you soon. Stay safe and study hard.