Macroglobulinemia

Transcription

- [Voiceover] In order to discuss Waldenstrom macroglobulinemia, I'm gonna start with a story and this story is set in Sweden in the 1940s. And at that time there was a young physician in Sweden by the name of Jan Waldenstrom and he noticed a peculiar constellation of symptoms in a few of his patients and these symptoms included bleeding, some visual changes, such as double vision and blurry vision, headaches, and generalized weakness. Now, these four symptoms on their own weren't necessarily that alarming, but the surprising thing was when he went to draw their blood to perform tests on them, he noticed that it was a little bit more difficult to draw their blood than it was for other patients. It was almost as if their blood was thicker and as he was thinking about all these different patients, he wondered if all these findings might be related. And in fact they were, so he named this constellation of symptoms hyperviscosity syndrome which literally means thick blood. Now, it turns out that these patients had a rare form of cancer in their blood, and this disease is now named after this Swedish physician who discovered it. It's known as Waldenstrom macroglobulinemia. So now that we know what Waldenstrom macroglobulinemia looks like, what exactly is it? Well, it's a disease that occurs in the bone marrow. So let's draw in a bone here and the bone marrow is the center portion of the bone and it's where blood cells are produced. So I want to highlight a few types of cells that are located here in the bone marrow. The first type of cell I'll put in here in red, and these cells produce red blood cells. And then another cell in here are the precursors to platelets. And then the last type I'm gonna put in green here and these cells are the precursors to plasma cells. So Waldenstrom macroglobulinemia is a disease of these cells, these precursors to plasma cells and for this reason it's considered a plasma cell dyscrasia. So I'll just write that in over here, and dyscrasia really just means dysfunction, so I'm gonna just cross it out and write here, dysfunction. 'Cause that's a, I think that's a little bit easier way of understanding what plasma cell dyscrasias are. They're just really dysfunction of plasma cells. So normally these precursor cells make plasma cells and then plasma cells make antibodies which I'll just draw in here. Now, antibodies are also known as immunoglobulins and I'm gonna just abbreviate that IG. IG for immunoglobulins. Now what happens in Waldenstrom macroglobulinemia is that these plasma cell precursor cells, they become neoplastic, or cancerous and this means that they grow and replicate uncontrollably. So let me just draw that in here, and I'm gonna represent these dysfunctional plasma cell precursor cells with a solid filled in circle and so they replicate and grow and as they do this they produce a large amount of immunoglobulins and they're actually producing a specific type of immunoglobulin known as IGM. So let me just add an M here. So, an immunoglobulin looks something like this. Well, an IGM is a specific type of immunoglobulin that's actually a combination of five immunoglobulins, so it looks something like that. When you have these dysfunctional or neoplastic plasma cells, they're producing lots of this IGM. And IGM is the largest of all of the immunoglobulins and it's a protein, so as you're producing all of these proteins, they actually start to clog up the small vessels in the small blood vessels and this results in the symptoms of hyperviscosity syndrome, such as the bleeding, visual changes, headaches, weakness, and definitely this thickening of the blood. So now we have a general understanding of the pathophysiology of Waldenstrom macroglobulinemia and that it's a cancer of these plasma cell precursor cells that produce large amounts of IGM resulting in this hyperviscosity syndrome. Well, how is it diagnosed? Well, the best way to diagnose Waldenstrom macroglobulinemia is with a bone marrow biopsy. And the biopsy will actually show these cancerous cells. Now, unfortunately, Waldenstrom macroglobulinemia is not a disease that we can cure, but we can treat it and there's really two aims to the treatment of Waldenstrom macroglobulinemia and the first is symptomatic. And by this I mean treating the symptoms of hyperviscosity syndrome. And to do this, individuals go through a procedure known as plasmapheresis, and what this means is that the blood is kinda removed from the body and all of these immunoglobulins are filtered out and then the blood is returned to the body. So that's kind of a simple explanation of what plasmapheresis is. So, if you remove these immunoglobulins, you're not gonna have the clogging up of the blood vessels and you won't have the symptoms of hyperviscosity syndrome. But this is really just treating the symptoms. It's not doing anything to the underlying disease. So the other aim of treatment is to decrease the disease progression. Like I said, it can't be cured, but you can slow the disease progression. And this is accomplished with different regimens of chemotherapy. So, Waldenstrom macroglobulinemia is a plasma cell dyscrasia, or dysfunction of plasma cells in which there is a overproduction of the immunoglobulin IGM and this results in thickening of the blood in a condition known as hyperviscosity syndrome, which is demonstrated by increased bleeding, some visual changes, headaches, weakness, and this obvious thickness of the blood.