6 min
Tasty Morsels of Critical Care 058 | Haematological malignancy Tasty Morsels of Critical Care
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- Medicine
Welcome back to the tasty morsels of critical care podcast.
Of the many things I poorly understand, I suspect that haematology holds a special place. Knowing the intricacies of the haematological malignancies was not exactly core knowledge for emergency medicine and to be fair an exhaustive knowledge is hardly key to ICM either. However in ICM there is a need to have a broad understanding of what some of the haematological acronyms might mean given that a fair number of these patients end up in the ICU. Most of this post will be navigating the basics of the diseases rather than super specific ICU management.
Oh dedicates a whole chapter, number 101 to the haematoloigical malignancies implying that it is certainly worth our attention. As a broad definition haematological malignancies involve the bone marrow or the lymphoid tissue, they occupy a different niche in the oncology world with the haematologists running the show rather than the general oncologists. They are also distinct in histology and outcomes from the solid organ malignancies.
We’ll start with the leukaemias and these can be split neatly into myeloid and lymphoid leukaemia. The cells gone bad in AML are the myeloid precursor cells, the cells gone bad in ALL are the lymphoid precursor cells. This type of statement is however only useful if you have any concept of how a myeloid precursor cell is different from any other type of cell in the bone marrow.
The attached image on the show notes, comes from the leading source of all medical knowledge, wikipedia. It’s a nice overview of the different types of cells stemming (see what i did there…) from myeloid and lymphoid precursors. It clearly works really well as an educational aid in audio form…
Myeloid cells differentiate into, well, most of blood cells that appear on your FBC, things like red cells, platelets, neutrophils, basophils. On the other hand, lymphoid cells have a much smaller and narrower family tree differentiating into different types of lymphocytes and plasma cells.
For AML there are a variety of causes from various genetically triggered issues, to transformation from a myelodysplastic syndrome or related to prior chemo or radiotherapy. It also includes the very ICU relevant disease of acute promyelocytic leukaemia. As a result, expect to see more AML in the older adult population. ALL is much more common in younger people with a much heavier CNS component, hence the prevalence of intra thecal treatment.
Each of the acute leukaemias has it’s own chronic version. With CLL being a form low grade lymphoma. CML begins as a chronic, somewhat indolent process that accelerates towards a blast crisis towards the end of the disease and for most people is more of a comorbidity than a malignancy.
Lymphomas, understandably come from lymphoid cells, these could be b cells or t cells for example. Classically lymphomas get lumped into two big categories of hodgkins and non-hodgkins with the former generally having the better outcomes.
Finally on the list of common haematological malignancies is multiple myeloma. This is a cancer of plasma cells which are the grown up and left home versions of B lymphocytes. In general plasma cells have developed to produce large amounts of proteinaceous antibodies and are triggered as part of an immune response. In myeloma they are inappropriately making large amounts of their specific protein or globulin reflected in the high total protein count and hyponatraemia associated with this disease.
So that’s a very broad, sub medical student overview of the different malignancies but why would they end up in your ICU?
Sepsis is probably number 1 on the list.
Welcome back to the tasty morsels of critical care podcast.
Of the many things I poorly understand, I suspect that haematology holds a special place. Knowing the intricacies of the haematological malignancies was not exactly core knowledge for emergency medicine and to be fair an exhaustive knowledge is hardly key to ICM either. However in ICM there is a need to have a broad understanding of what some of the haematological acronyms might mean given that a fair number of these patients end up in the ICU. Most of this post will be navigating the basics of the diseases rather than super specific ICU management.
Oh dedicates a whole chapter, number 101 to the haematoloigical malignancies implying that it is certainly worth our attention. As a broad definition haematological malignancies involve the bone marrow or the lymphoid tissue, they occupy a different niche in the oncology world with the haematologists running the show rather than the general oncologists. They are also distinct in histology and outcomes from the solid organ malignancies.
We’ll start with the leukaemias and these can be split neatly into myeloid and lymphoid leukaemia. The cells gone bad in AML are the myeloid precursor cells, the cells gone bad in ALL are the lymphoid precursor cells. This type of statement is however only useful if you have any concept of how a myeloid precursor cell is different from any other type of cell in the bone marrow.
The attached image on the show notes, comes from the leading source of all medical knowledge, wikipedia. It’s a nice overview of the different types of cells stemming (see what i did there…) from myeloid and lymphoid precursors. It clearly works really well as an educational aid in audio form…
Myeloid cells differentiate into, well, most of blood cells that appear on your FBC, things like red cells, platelets, neutrophils, basophils. On the other hand, lymphoid cells have a much smaller and narrower family tree differentiating into different types of lymphocytes and plasma cells.
For AML there are a variety of causes from various genetically triggered issues, to transformation from a myelodysplastic syndrome or related to prior chemo or radiotherapy. It also includes the very ICU relevant disease of acute promyelocytic leukaemia. As a result, expect to see more AML in the older adult population. ALL is much more common in younger people with a much heavier CNS component, hence the prevalence of intra thecal treatment.
Each of the acute leukaemias has it’s own chronic version. With CLL being a form low grade lymphoma. CML begins as a chronic, somewhat indolent process that accelerates towards a blast crisis towards the end of the disease and for most people is more of a comorbidity than a malignancy.
Lymphomas, understandably come from lymphoid cells, these could be b cells or t cells for example. Classically lymphomas get lumped into two big categories of hodgkins and non-hodgkins with the former generally having the better outcomes.
Finally on the list of common haematological malignancies is multiple myeloma. This is a cancer of plasma cells which are the grown up and left home versions of B lymphocytes. In general plasma cells have developed to produce large amounts of proteinaceous antibodies and are triggered as part of an immune response. In myeloma they are inappropriately making large amounts of their specific protein or globulin reflected in the high total protein count and hyponatraemia associated with this disease.
So that’s a very broad, sub medical student overview of the different malignancies but why would they end up in your ICU?
Sepsis is probably number 1 on the list.
6 min