Basophilic Stippling

[StilgarMD]

FA (2016) says that Basophilic stipppling can result from Lead poisoning, sideroblastic anemias, and myelodysplatic syndromes.

My understanding of Basophilic stippling is a compromised ability to degrade rRNA, which leads to a build up and these small basophilic aggregates.

Lead poisoning leads to the denaturing of the ribonucleases required to do this. I don't understand how Sideroblastic anemias or myelodysplastic syndromes could result in this. I could see sideroblastic anemias potentially causing it through the aggregation of Iron, which may act like Lead, but I can't find this explanation anywhere.

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[worldbeater]

My understanding of Basophilic stippling is a compromised ability to degrade rRNA, which leads to a build up and these small basophilic aggregates.

Nice, yeah this works with the Prussian blue stain. I got a UWorld question wrong on this, I didn't know about the rRNA portion. My thought was basophilic stippling is automatically lead poisoning, I don't go with any other differentials.

 

[worldbeater]

I was just reading something connected to this and I thought I would share...

-Basophilic stippling occurs due to too many heinz bodies. What are heinz bodies? Precipitated or oxidized protein (hemoglobin) in the RBC

-rRNA for the stain makes sense because this is the only thing that is found in the nucleolus of a ANY cell (UWorld question), which would include a red blood cell. rRNA is also released from ribosomes, which cause the "studded" appearance, so this could be picking up the stain also/instead.

-Lead poisoning is your 90% answer when you see basophilic stippling, meaning 9/10 times you will get a point on a exam with this choice. The other differentials you mentioned listed in FA are the 10%; although correct, it's not the most common differential.

 

[walakin25]

both lead and myelodysplastic syndrome are causes of sideroblastic anemia. the exact mechanism of basophilic stippling is still not clearly elucidated but its related to dyserythropoiesis.

 

[StilgarMD]

I was just reading something connected to this and I thought I would share...

-Basophilic stippling occurs due to too many heinz bodies. What are heinz bodies? Precipitated or oxidized protein (hemoglobin) in the RBC

-rRNA for the stain makes sense because this is the only thing that is found in the nucleolus of a ANY cell (UWorld question), which would include a red blood cell. rRNA is also released from ribosomes, which cause the "studded" appearance, so this could be picking up the stain also/instead.

-Lead poisoning is your 90% answer when you see basophilic stippling, meaning 9/10 times you will get a point on a exam with this choice. The other differentials you mentioned listed in FA are the 10%; although correct, it's not the most common differential.

1) I vaguely recall something about Heinz bodies leading to Basophilic stippling, but it i can't find it in any of my sources.

2) Basophilic stippling represnts rRNA aggregates. The rest of what you've said isn't really relevant to this discussion since RBCs are enucleated cells, and have no Nuclei or Nucleoli to speak of. rRNA isn't just found in the nucleolus, it is synthesized there by RNA Pol I. Once synthesized it aggregates with protein to form Ribosomes. Ribosomes are 60% rRNA and 40% protein, and the protein part isn't even the catalytic part, it is just a structural component (the peptidyltransferase activity is actually ribozyme activity). Anywhere you see Ribosomes (i.e. the cytoplasm and RER of all cells) is somewhere you will see rRNA. Given that RBCs have intact proteasome activity (or at least I haven't heard otherwise), they can degrade the protein component just fine. It the presence of Lead, the Ribonuclease typically responsible for degrading the rRNA component is denatured (much like Pb does ALAD and Ferrochelatase), which leads to these aggregates.

3) I'll probably just keep this in mind.

 

[Phloston]

https://en.m.wikipedia.org/wiki/Zinc_protoporphyrin

 

[worldbeater]

This is a good discussion..

1) I vaguely recall something about Heinz bodies leading to Basophilic stippling, but it i can't find it in any of my sources.

This is in the Notes in the Anemia chapter

2) Basophilic stippling represnts rRNA aggregates. The rest of what you've said isn't really relevant to this discussion since RBCs are enucleated cells, and have no Nuclei or Nucleoli to speak of. rRNA isn't just found in the nucleolus, it is synthesized there by RNA Pol I. Once synthesized it aggregates with protein to form Ribosomes. Ribosomes are 60% rRNA and 40% protein, and the protein part isn't even the catalytic part, it is just a structural component (the peptidyltransferase activity is actually ribozyme activity). Anywhere you see Ribosomes (i.e. the cytoplasm and RER of all cells) is somewhere you will see rRNA. Given that RBCs have intact proteasome activity (or at least I haven't heard otherwise), they can degrade the protein component just fine. It the presence of Lead, the Ribonuclease typically responsible for degrading the rRNA component is denatured (much like Pb does ALAD and Ferrochelatase), which leads to these aggregates.

I agree with you on this point about no nuclei,. I actually should have thought about this harder because I did know RBCs don't have mitochondria and require on outside glucose to power themselves..no peripheral glucose causes them to lyse and cause hemolytic anemia. The RNA polymerase I point is a UWorld question, I agree with that.

3) I'll probably just keep this in mind.

Cool

Thanks for the points.

 

[worldbeater]

Ah the formatting didn't work, I'll try again:

This is a good discussion:

1) I vaguely recall something about Heinz bodies leading to Basophilic stippling, but it i can't find it in any of my sources.

It's in the Notes under the Anemia section if you have that book

2) Basophilic stippling represnts rRNA aggregates. The rest of what you've said isn't really relevant to this discussion since RBCs are enucleated cells, and have no Nuclei or Nucleoli to speak of. rRNA isn't just found in the nucleolus, it is synthesized there by RNA Pol I. Once synthesized it aggregates with protein to form Ribosomes. Ribosomes are 60% rRNA and 40% protein, and the protein part isn't even the catalytic part, it is just a structural component (the peptidyltransferase activity is actually ribozyme activity). Anywhere you see Ribosomes (i.e. the cytoplasm and RER of all cells) is somewhere you will see rRNA. Given that RBCs have intact proteasome activity (or at least I haven't heard otherwise), they can degrade the protein component just fine. It the presence of Lead, the Ribonuclease typically responsible for degrading the rRNA component is denatured (much like Pb does ALAD and Ferrochelatase), which leads to these aggregates.

I agree with you on this point about no nuclei,. I actually should have thought about this harder because I did know RBCs don't have mitochondria and require on outside glucose to power themselves..no peripheral glucose causes them to lyse and cause hemolytic anemia. The RNA polymerase I point is a UWorld question, I agree with that.

3) I'll probably just keep this in mind.

Cool

Thanks for the points.

 

[Transposony]

Asked Dr Tisdall and according to him any condition due to dyserythropoiesis can lead to basophilic stippling which includes congenital and acquired pyrimidine 5′-nucleotidase deficiency (e.g. thalassemia).
Basically anything which messes up erythropoiesis can lead to basophilic stippling.

Think it's also mentioned in Up to date:
http://www.uptodate.com/contents/evaluation-of-the-peripheral-blood-smear