Hello! Welcome to med-dose podcast. Today we are going to look at abnormal morphologies of Red blood cells and various inclusions that might be present in RBC. Transcript for this podcast is available on sciencetidings.com. You can find the link in description of this episode on your favourite podcast app. Let’s get this started without any delay. You can find a picture of all the abnormal morphologies on the website.
Before you try to understand and memorise the various abnormal morphologies of red blood cells, you want to understand two terms – Anisocytosis and Poikilocytosis. Anisocytosis indicates presence of cells of varying sizes. Poikilocytosis indicates presence of RBC of varying shapes.
First cells that we are going to talk about are acanthocytes or spur cells.
Acanthocytes or Spur cells
- Description: RBC have projections of various sizes at irregular intervals all over them.
- Associated Pathology: They are associated with Liver disorders, abetalipoproteinemia, neurodegenerative disorders.
Next up, we are gonna talka bout Echinocytes or burr cells.
Echinocytes or Burr Cells
- Description: RBC have smaller and more uniform, evenly spaced projections compared to acanthocytes. To put it in simpler terms, burr cells or echinocytes have projections just like spur cells or acanthocytes but those projections are much smaller and evenly spaced on the RBC surface.
- Associated Pathology: These are associted with Liver disorders, Uremia, Pyruvate deficiency, Artifacts
Liver disorder is something which is common between both acanthocytes and echinocytes. Next Up, Tear drop cells or dacrocytes.
Tear drop cells or Dacrocytes
- Description: Tear drop shaped cells
- Associated pathologies: Associated with bone marrow infiltration eg, myelofibrosis. Tear drop cells may also be seen in Thalassemia.
Helmet cells or Schistocytes
- Description: Fragmented RBC
- Associated pathologies: First thing you wanna remember is MAHA, Microangiopathic hemolytic anemia. Examples are DIC, Thrombotic thrombocytopenia purpurin or HUS, Second thing you wanna remember is mechanical hemolysis that can be caused by Heart valve prosthesis etc.
Bite cells or Degmacytes
- Description: One or more semicircular punches on cell margin resembling bite marks.
- Why do they occur? Due to removal of Heinz bodies by splenic macrophages. What are Heinz bodies? They are desaturated haemoglobin inclusions.
- Associated pathologies: G6PD deficiency
- Description: elliptical cells
- Why do they occur? Caused by mutation in genes encoding RBC membrane protein, eg: spectrin
- Associated pathologies: Hereditary elliptocytosis
- Description: Spherical RBC without central pallor
- Associated pathologies: Hereditary Spherocytosis, Autoimmune haemolytic anemia.
- Description: Large RBC
- Associated pathologies: Megaloblastic anemias
- Description: Bulls eye appearance
- What are the associated pathologies? Let me give you a hint: Mnemonic is HALT. H for HbC disease or hemoglobinopathies, A for Asplenia, L for Liver disease,T for Thalassemia
- Description: Sickle shaped RBC
- Associated pathologies: Sickle cell anemia
Okay, We are done with abnormal morphologies. Let’s test your memory. Here we go in 3 2 1
What kind of RBC are seen in G6PD deficiency.?
Clue: Heinz bodies are formed which get removed by splenic macrophages. Yes You guess it right! Bite cells or degmacytes
What is the mnemonic for Target cells
What are the associated pathologies? Let me give you a hint: Mnemonic is HALT. H for HbC disease or hemoglobinopathies, A for Asplenia, L for Liver disease,T for Thalassemia
RBC in myelofibrosis?
Hint: Myelofibrosis involves bone marrow infiltration, soooooo we have tear drop RBC or dacrocytes. You can remember it by the first aid mnemonic. RBC sheds a a tear because it is squeezed of its home in the bone marrow.
Okay now let us look at the inclusions within the RBC. We will look at both RBC in bone marrow as well as the peripheral blood. First let’s look at inclusions in the RBCs of the marrow.
Iron Granules, like in ringed sideroblasts
Mitochondria contain excess iron. These mitochondria are arranged as a ring around the nucleus. These perinuclear mitochondria appear as ring when the cells are visualised by pruissian blue stain
Associated condition is Sideroblastic anemia. Causes of sideroblastic anemia is another topic of discussion, but in brief, lead poisioning, myelodyspalstic syndromes, alcoholism etc.
Now let us look at the findings of RBC on peripheral smear
These are basophilic and are mere nuclear remnants. they do not contain any iron and are usually cleared by slenic macrophages.
Associated pathology: So where do we get to see the Howell-jolly bodies? We know that splenic macrophages remove them. So they are seen when splenic macrophages do not remove them. this can happen when there is no spleen – asplenia or hyposlenia as in sickle cells disease.
It is evident from their name that these inclusions are basophilic. Just like Howell Jolly’s bodies, these do not contain iron. These are just basophilic ribosomal precipitates.
It is seen in Sideroblastic anemia and thalassemias In case of sideroblastic anemia, we also learnt that we see ringed sideroblasts in the marrow. Basophilic stippling is seen on peripheral smear.
These are basophilic inclusions seen in sideroblastic anemia. But they contain iron.
So in case of sideroblastic anemia we see basophilic stippling, which doesn’t contain iron and pappanheimer bodies which contain iron on peripheral smear.
These contain iron, because they are denaturated and precipitated hemoglobin. These are responsible for formation of bite cells or degmacytes when slenic macrophages decide to have a bite and remove the heinz bodies.
Heinz bodies require supravital stain to be visualized, and they are seen in G6PD deficiency.
Final note: Iron containing RBC inclusions are ringed sideroblats (perinuclear mitochindria) in marrow , pappenheimer bodies and heinz bodies (denaturated hemoglobin) in peripheral smear. Whereas, Howell Jolly bodies and basophilic stippling do not contain iron.
Thanks for listening. Bye.