Sept. 7, 2025

PIMA: The Anaemia That You Didn’t Know About, But Really Should. With Dr Cynthia Lucidi and Dr Claire Sharp. Bonus - Live at IVECCS

PIMA: The Anaemia That You Didn’t Know About, But Really Should. With Dr Cynthia Lucidi and Dr Claire Sharp. Bonus - Live at IVECCS
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Season 1

Today’s bonus IVECCS live session wasn’t your average ‘clinical 101’. I had the absolute privilege of getting two brilliant minds on the yellow couch, and … wow. 

Apparently 1 + 1 = 🤯 !!

 

Clinical pathogist Dr Cynthia Lucidi joined me to unpack her talk on Diagnosing Ineffective Hematopoiesis.  If you’re a bit lost with that title - don’t worry, so was I!  So I brought backup: ECC legend Dr Claire Sharp joined me to ask the smart questions, and together, they cracked open a topic every GP and ECC vet needs to understand: PIMA – Precursor-Targeted Immune-Mediated Anaemia. (If you’ve ever managed an anaemia case that almost looked like IMHA but just didn’t quite fit, or just an anaemia that didn’t want to fit into ANY of the boxes, it was probably this!) 

This one started out GP-friendly, but with two minds like these-it escalated fast. Expect specialist-level gold. You’ll want to give this one your full attention. But I promise - it’s worth it!

 

What we cover:

  • Defining ineffective haematopoiesis and how it differs from hypoplasia
  • Diagnostic criteria and differentials for PIMA vs. IMHA
  • Importance of timing and interpretation in persistent non-regenerative anaemia
  • Why bone marrow aspiration is underused and how to perform it effectively
  • Pathologist tips on identifying spherocytes and phagocytosis artefacts
  • Challenges of diagnosing IMHA and PIMA in cats
  • Role of transfusions and crossmatching in long-term PIMA management
  • Timeframes for response and remission in PIMA treatment
  • When to consider splenectomy for refractory cases
  • Clinical significance of myelofibrosis in dogs with PIMA
  • Educating clients and general practitioners on prognosis and referral timing

 

Click here⁠⁠ to access all of our clinical content at IVECCS special rates.

This episode is one of our live recordings from IVEX 2025 where I've been interviewing some of the world class speakers for highlights and key takeaways from their talks.To hear all of the full interviews when we release them, and to access more than 600 other episodes on small animal medicine, surgery, and emergency critical care with all of the associated show notes, go to vvn.supercast.com.
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OK, we hope you enjoy this episode.Right.Special one for this session, we have Professor Cynthia Lucidi.Yeah.Who is a pathologist, correct?
Yeah.Clinic Clinical clinical clinical pathologist.Pathologist.Very important differential, right, Right.Yeah, yeah.No cutting up dead things.And joining me is the well known to our audience, Dr. Clay Sharp.I'm so thrilled to have Clay here because of the topic which is diagnosing ineffective hematopohesis, right, which I sad thank you.
I was going.To say.Because I read that too, but I go, I understand the words, but I don't really know anything about.But if I think about it hard, probably some stuff.So what we'll do?I will ask the stupid questions.There's no super question.And then click and take it to the next level.
So should we start basically?So sad, that's what it is.That's what you're talking about.But when the bone marrow is sad and it's not doing its thing, is it basically just to just define what we're talking about?Yeah, it's when the bone marrow is doing everything it can.It's making a lot of cells, but the cells are not going out.
As opposed to.As opposed to when the bone marrow is effective, the cells are being produced and effectively going out to blood to perform their function.When the production is ineffective, they're being produced, but they're not going out into blood to perform their function.
They're stuck or they're dying in the bone marrow.The bone marrow is very active.It's doing everything it can to produce.It's producing a lot, but the cells are stuck in there.Do you have a different kind of pathology where they're just not producing at all?Yes, yeah, so, so.That wipes out the precursors or something.
It's a great question.It's almost like you have my slides in front of you.Yeah.So kind of taking a step back, you know, the main indication for a bone marrow collection, there's many, but the main 1 is when there's cytopenias.So you have either an anemia, A neutropenia, or more rarely A thrombocytopenia.
People don't usually collect marrow because of thrombocytopenia because you can diagnose what's causing that without going from marrow.But most of the time you have an anemia or a neutropenia or both together, or thrombocytopenia may be included in those cytopenias.And that's why you collect marrow to see what's the problem in the production, because the marrow is the primary place to produce those cells.
When you collect the marrow, there's two primary patterns that you can find.Either the production is decreased, that's your hypoplasia or aplasia, and there's a laundry list of differentials for that and different treatments for those.Or the production is increased and then there's a laundry list of differentials there and the treatments for those in the case of having cytopenias and the production being increased, that's the ineffective production because they're not going out.
But then the other side of the coin is the production may also be decreased.OK.Now while we focused yesterday was on the differentials for when the production is increased?One of the things that I find so fascinating about Cynthia's work is the I think historically these diseases of ineffective Eritreal places were thought to be rare, and I think we're now realizing they're actually not rare at all.
So, so just to put me in the picture, so these are again with the Pima specific, we'll get to the white blood cells.But so these are going to be anemic patients.Yeah, they're going to come to me with anemia.Absolutely.And then I want to do my CBCS and stuff and I want to go, well, there's not reticular sites, there's no evidence of regeneration exactly.
And then we're going to go, well, it's iron is fine.So it's not an iron deficiency.So then you start thinking, OK, well.Let's exactly so it's when you have a persistent no regenerative unexplained anemia.So you rule out iron deficiency, chronic renal failure, things like that.
And it's important to to pay attention to the persistence.So you need to make sure you are past that pre regenerative window of three to five days.Because if bone marrow is in homeostasis and health and you suddenly develop an anemia, you're going to have a hypoxia release of erythropoietin.
And it takes about three to five days for the bone marrow to increase production enough to be released in reticulocytes.So you want to make sure you're past that five day window to go for bone marrow because it's a pretty invasive procedure.You don't want to do it if you don't have to and.We were just talking about the fact that we really need more or universal definitions of what Pima is.
We now have an ACV and consensus statement on the diagnosis of IMHA and that does not include evidence of regeneration in that definition, but it does include evidence of peripheral erythrocyte destruction, spherocytosis, positive saline agglutination test, positive direct antiglobulin test.
And some of our patients seem to have, for example, a low number of sphericides but then have a non regenerative anemia.So do you think that there's overlap between the classic IMHA diagnostic algorithm and Pima cases where they have some bone marrow destruction of precursors and some peripheral destruction?
Yeah, I love that question.I think of myself as a purist.So if we like take a little travel down history lane here, I guess.When I started my PhD and the Pima was assumed it should be an immunomitated disease, very commonly it was lumped into IMHA.
And so, you know, in the past it has been called non regenerative IMHA, non regenerative hemolytic anemia or, you know, variations of that name.And I, as a pathologist who tries to understand the mechanism of diseases, I try to separate these as much as we can.
Obviously, you know, it's biology, but I try to separate as much as we can.OK, here is 100% pure IMHA.Let's characterize this.This is what the patient looks like.This is the treatment.This is the prognosis.This is how long treatment takes.
And then there's Pima, pure Pima.And OK, let's characterize that.What does the bone marrow look like?How long does it take to respond?How many times?What is the relapse rate?So we first need to look at the disease in a pure sense so we can understand what that disease is.
And then we start getting a little bit more nebulos by combining 2 things that are overlapping.And so to answer your question, in my experience, I'm grabbing a number out of the air, OK.So the vast majority, virtually all Pima cases are pure Pima.
Pima is defined as not being a hemolytic disease.So in my definition, and that's maybe arguable and other people may disagree, but my definition of hemolysis is destruction of mature red blood cells.
And now you can split that hair.The reticulocytes, you know, are they included in that or not?And then we can split that hair.I'm not sure what the answer is for that, but to me, to help characterize and define things, I like to think of hemolysis as destruction of mature red blood cells.
And that's why you said that.Ghost cells, spherocytes, red blood cell glutination, pink plasma ichteros.That is evidence of hemolysis.In Pima.You don't have destruction of mature red blood cells, you have the selective destruction of the precursors only in the vast majority of cases, a couple hairs just bled there.
So one is the erythroid precursors have less hemoglobin than a fully mature red blood cell, but they still have some hemoglobin.And so if the destruction of those cells is significantly increased, it is possible to see bilirubin that is very mildly increased in some of those patients, but they're typically not ichthyric.
So you you may have a mild hyperbilirubinemia, but you don't have ichterus or jaundice.The other here to split there is maturation of red blood cells occurs in a continuum obviously with some surface membrane proteins being increasingly expressed as they mature and some being decreasingly expressed as they mature.
And the immune system, we think of Pima in being in a spectrum of immune meditated anemias with IMHA being destruction of mature red blood cells, Pima destruction of precursors, Prca being destruction of the very early progenitor that just wipes everyone out when it's attacked.
And it is possible that the immune system at some point is seeing an antigen that is on the surface of both the mature red blood cell and the precursor at the same time.And so we do have some rare pneuma cases that also have ghost cells or spherocytes or red sublutination, but that's very rare.
In my practice, we have a big blood bank in our hospital and so cases come to us for transfusion and often they've had a transfusion or two somewhere else.So they come to us for cross matching and availability of lots of different blood to make sure that we can find compatible donors.
And it's very common that we have cases, admittedly in this tertiary population that screen before they get to us that perhaps fulfill the supportive criteria for IMHA.They have some spirocytosis, they have a mild hyperbilirubinemia.
And by the time they come to us, often they're coming to us on day 34567.Since diagnosis of their anemia, because they have started immunosuppression somewhere else, they've been labeled as IMHA, they've had a transfusion or to somewhere else and they continue to need blood.
And so it's a little bit hard to know in those cases because the spherocytes could potentially be associated with the transfused blood.We don't know if they were present initially because we don't always have ACVC that was read by clinical pathologists.And I do think that sometimes identifying spherocytes is difficult in practice and you need, you know, nicely prepared blood smears, which I don't think always happens in our practice too.
But most importantly, they're non regenerative and then non regenerative beyond a time which they should be.Regenerative dogs and cats.More, more cats.And I'll ask that in again in a second.Both OK.Yeah, we we see both in this scenario and so a lot of those cases we are performing a bone marrow, I love to bone marrow, I did a little bit.
Of yeah, go you.Yeah, I did a little go you.Please do.I said no, bone marrow is a verb.I love to bone marrow.Yeah, I'm using it in that way.And I I love to talk about bone marrow because so many clinicians think it's hard and they think it's invasive and they're worried about doing it in an animal that's thrombocytopenic, you know, that has pen cytopenia.
They're worried it's going to bleed, and while it's an invasive procedure, it's not actually that much more invasive than collecting a blood sample from an external jugular vein.And it can be done very quickly.You know, I always joke without anaesthesia students that I will have finished the bone marrow before they put their monitoring on the dog.
So I'm going to clip and prep while they're getting their patient monitoring on after anaesthesia induction.And I'll be finished before they've written their first set of vitamins.And they always sort of laugh awkwardly at me when I say that.And then I have, you know, before they've hooked up all their monitoring, written down their first set of vitals.
I have my bone marrow sample and then I say you can turn off the anesthesia now.So I think dispelling the myth that bone marrow is difficult to collect is important.You have to be trained how to collect bone marrow well, because when you collect a good sample, it makes a world of difference.
And a lot of the diseases that we're diagnosing at least through an emergency and critical care perspective and I would likely say also general practice perspective off of bone marrow are diseases that can be diagnosed off an aspirate and bone marrow as opposed.To a core biopsy.So you're smearing it.
You're not sending a chunk of.Bone.Well, I do a couple of things and it's probably good for us to talk about the way that we collect and prepare samples.But I submit bone marrow on slides and I also submit liquid bone marrow in ETA so that they can.
Dissolve it in.Dissolve it in because I'm imagining you're not getting a large quantity.It's.Probably good to talk about and I collect.So many, so many comments from all the things we're saying.We've never spoken before so I'm fascinated to hear opinion, but I actually collect directly into EDTA in my syringe because bone marrow is super clotty and sometimes it doesn't flow as well out of the marrow as you might like.
Often it flows like blood.It comes out of the marrow quite quickly, the liquid bone marrow, but sometimes it's a little slow and you'll activate coagulation as you stick a giant needle in the bone marrow.And so what's giant?Talk me through the very basics.I've never done it before.How am I going to?How and where am I going to collect bone marrow?
Do you want to start or do you want to critique what I say?Well, no, I just I'm taking notes here because I want to make sure don't forget the things you're saying.So, so let's, let's just pause here for a second because I have too many thoughts to share.So you mentioned that those dogs are coming to you already on treatment for presumptive IMHA and you don't know if a spherocyte was seen because it's very challenging to assess that?
Particularly now that they've had two transfusions and they could be spherocytes associated with.Yeah.So let's just unpack that for a second.So after we give transfusion to an animal there, even if there was a negative cross match, so the cross match is successful, you go ahead and give the transfusion.
Even if that happened, it's possible that there is still some minor incompatibility reactions that are causing the transfused cells to be attacked by the immune system and increasing their turnover.And the transfused red blood cells may become spherocytic in that process.
So you may start having sites that are not from the patients, they're just from a minor incompatibility reaction that couldn't be seen in the cross match.And I would say most of our veterinarians are not cross matching before they give their first old transfusions, particularly not for patients that they think have IMHA.
And that's a whole nother discussion.But I also think that some of this is is not necessarily an incompatibility at all, or that it's related to erythrocyte storage.Leisure.Just aging.Right.The cells are all they're expressing antigens on their surface that say I'm an old red blood cells spleen, please remove me.
I'm at the end of my life.Yeah.And so the spleen is trying to do its job.And so it's not even associated with incompatibility.They can so genetically.So basically don't trust CBC once a dog's head transfusion.Don't trust the president sense of spherocytes if that's why you're basing your MHA diagnosis on.
Don't use that as your sole indicate indicator.If you have a dog that has seen a transfusion.And then I'm going to kind of go on a limb here and expand on that, that even if the dog did not get a transfusion yet, it is very challenging to accurately call spherocytes.
I am very picky about this and I have a very high threshold for calling spherocytes because spherocytes can be an artifact that forms in health and healthy animals without having disease.
Towards the feather, the edge of this mirror.So if you look at a blood smear, if you get towards the feather, the edge, all the cells will lack a central paler.And that's what a spherocyte in theory, you know, the main, the main criterion for a spherocyte is lacking a central paler.If you go towards the feather that everyone lacks a central paler.
And so you have to go inwards towards the optimal zone towers, sometimes even the body of this mirror to force those red blood cells to start showing a central paler.And the more you go, the more the central paler appears.And if you just keep going, the more the central paler keeps appearing until sometimes all the central, all the cells have a central paler and no one looks like a spherocyte right anymore.
And so that's a conversation I have often with my residents.They ask me where do you stop?I was like, I don't know, I have a very high threshold.And so some other things that help me in addition to the central paler is cells that appear to be smaller.
They actually have the same cell volume as a normal red blood cell.They don't with cytoplasm and that phytocytosis is just a loose membrane.So the volume is the same, but they appear smaller because when they are spread on a blood smear, they can't flatten, so just look smaller.
And then because they don't flatten, they look darker because now the light is going through a cell that is Sturge and going upwards.And so those cells lack a central power.They look smaller and they look darker.So you got to see those three things and away from the feather that to be able to accurately call spherocytes, which then my last dilemma here is which is virtually impossible to do in cats.
OK, so I'll just hand that thought.What looking for Spherocell?Looking for spherocytes because cats have smaller red blood cells than dogs and their central pallor is not as pronounced to begin with and so it's very difficult to assess for lack of central pallor and a smaller size in a cell that already is very small and lacks a central pallor for the most part.
So.I was going to ask, that's why I asked dogs or cats, because I recently did an episode just on feline anaemia.And in that conversation there's with a feline medicine specialist, she said watch out for cats and IMHA because they, they, they, she said they don't often don't get sphericides.
Is it a question of, oh, we don't see them?And the other thing she said is they will often get the red blood cells attacked in the bone marrow.So is it that they get Pima more or is it a like I, I just as he's talking, I'm like, well, that sounds very familiar.We have the epidemiologic data to say they get Pima.
So when when we say cats have different IMH as because they sometimes have Pima or not OK.I I don't know what is the data on incidence of IMHA versus Pima in cats because for multiple reasons, which is some of them being it's very challenging to diagnose IMHA in cats.
We don't really know a true prevalence.To me it needs to be confirmed by a Combs test.It's the closest we have to a task that is more accurate in cats.I don't know of anyone who is doing flow cytometry like a flow cytometry based comb test for cats, but you add a minimum.
You have to do a tube comb test for cats to confirm that you can't rely only on sphericide.Still not 100% sensitive, right?Do you tell?Would you still or?Is it the pumes is not a perfect test, but you know it doesn't have a no.Specific.But it doesn't have 100% sensitivity or specificity.
But you know, it's the best we have at this point.You can also look for ghost cells.But then ghost cells is another limb that I can go on because it can also be an artifact and it can overlap with osmotic fragile syndrome.So osmotic fragile syndrome can have.
Intermittently regenerative anemias, poorly regenerative sometimes that have a little bit of ghost cells and you can't make a diagnosis of MHA based on that.So to me in cats, you got to do a tube based home test to confirm my MHA.And then for the incidence of pema in cats, it's very poorly studied.
It's often lumped with PRCA or MHA.So there's no studies that I know of that that is looking in that puristic point of view, looking only at pema in cats.And that's a study I hope I can do in the future.But I feel that we.
Do make a diagnosis of what we believe to be Pima, we have less information about prognosis and response to treatment.So for dogs, I think for me as a clinician, the differentiation between Pima and IMHA is very important because it's going to change the expectations that I have for their response to immune suppression.
And the way that I educate the owner about how they need to be bought in and the duration of time over which they need to expect that the animal will come back to the hospital will require blood transfusion is very different between IMHA and Pima.And if people are not prepared for that, they get frustrated that they're two months down the track and the patient is not in remission.
Different how and which is better news?So IMHA is a disease that when it responds to immune suppression and the owners have time and money to get them through that first week, two weeks, they then don't need to come back for transfusions over time.
And we can talk about the way that they're immunosuppressed, how quickly people add second line immunosuppressants, etcetera.But that's maybe a topic for another day because I think that we are too aggressive adding adding second line immunosuppressants in from many of our cases.
But my experience with Pima is that those cases may not achieve immunologic remission for months, and they may need a transfusion every few weeks for a period of time.They may need a whole number of transfusions initially, especially if they have a PCV, you know 10812 when they first come to us and they're not going to be a stay in the hospital while you're really sick will transfuse you until you're close to immunologic remission and then you won't need to be readmitted unless you get an infection.
Pima cases often need to come back in my experience for outpatient transfusion.More like a plastic anemia type cases that need transfusion over time.Yeah.And I'll comment on that, that actually, honestly you want the Pima cases to be in and out the door very quickly to save money to the for the owner because they are going to have to come back.
Most likely they will come back for a second or third transfusion or four or five and any, any.I love what you said.It's fundamental to have that clear conversation of clear expectations with the owner where that Pima is going to take potentially months and potentially this dog is going to have to come back every single month to receive a transfusion until finally the immune system is controlled and the animal can start picking up.
And during that period of time, because of the time interval between transfusions, compatible cross matches become so much more imperative than an animal that receives a lot of transfusions in five days and then is an immunological remission because in those cases, they haven't reached their peak antibody formation against foreign erythrocyte antigens.
And so you may get away with some incompatibility in that time.And yes, you may have some delayed hemolysis, but you won't have an acute hemolytic transfusion reaction if you give incompatible blood on day three.But on week 3, if you give an incompatible transfusion, you'll absolutely have an acute hemolytic transfusion reaction even to non DEA 1 incompatibilities.
And so that becomes really important.The cross matches are vital.And if you want to get more granular about data for how long it takes to respond, so in our studies we looked at 66 Pima dogs and there was a group of responders and a group of quote UN quote non responders.
And we can talk about that in a second.But for the responders, the median time to respond to response with a regenerative response was about one month median, which means that some were much shorter than that and some were much longer than that.
And then the median time for remission with the hematocrit that was close to normal was about two months OK median time.However, however, if the no quote UN quote non responders were actually given a chance to respond instead of being optimized, they may have pushed those numbers a little higher.
And so the median time for response and for remission are probably more than one month and two months if we considered that the euthanized dogs would have taken longer to respond.And honestly, they were often euthanized before that one or two-month window.
So they were euthanized before they even were given a chance.True.Are we immunized?Praising the same as with IMH.It's a Prednisolone first line.Or same treatment, so 2 milligrams per kilo per day of Prednisone in some cases, some dogs in our studies have received a little bit more than that going up to four, 4 milligrams per kilo per day, but we tried to stay within two to avoid side effects and that.
Or dose based on a milligram per meter square basis, which might be a little bit better to account for the size range because larger dogs have much more pred intolerance and you can probably get them adequately immunosuppressed with a lower milligram per kilogram dose than the small dogs.
Because they take so much longer to show response that are we talking about secondary immunosuppressors if they don't respond And then because I mean by day 5 and you said we weren't going to that drabonhold, but most of us are going this isn't working, correct?And this is one of the reasons.Why recognizing that then they're, they don't have regeneration at day five and thinking could this have a precursor targeted etiology, getting your bone marrow sample, identifying maturation addressed arrest, identifying erythrophagocytosis in the bone marrow rather than just going with what somebody said on day one, which is this is IMHA getting the bone marrow, identifying that it's Pima, in my opinion would mean that I would not give a second line immunosuppressive to the majority of cases because majority of Pima cases, this is controversial, but many of them will respond to prey.
You just need to give them time, and if you add a second line immunosuppressive, you're not necessarily going to be able to get them off pred sooner because they're not in remission for months.So now you're giving 2 immunosuppressives for months.And certainly in our area in Perth, WA climate, sort of like the A&M experience, we see a lot of secondary fungal infection and weird and wonderful bacterial infections like malleoidosis as a consequence of cyclosis specifically.
Cyclosporin more so than bread.Correct.More so than bread and particularly a combination and certainly three drugs.There are still clinicians prescribing 3 drugs which the ACBM consensus statement recommended against.And I think we should avoid particularly in places in the world where we do see a lot of secondary infections because sometimes they'll survive their immune mediated disease and they'll be euthanized from a catastrophic.
Infection I want to comment on on you know, I love your thought process on setting up the expectations with the owner that this is going to take a long time, you know, potentially adding a second drug or not, depending on where you live on the globe and the and the experience and how comfortable you feel.
And what are the odds of secondary infection?Doctor Jakowitz spoke after me yesterday.So I talked about diagnosis of those diseases and he talked about the treatment because he's the clinician, I'm just a pathologist.And but what he commonly says and what he discussed yesterday is that at some point we start to kind of classifying those dogs as, OK, this is not responding at this point.
And sure, we can push this with immune suppression for however much longer.But what is the cost in terms of side effects?And when do you call it a day on immune suppression?And in the past, he used to kind of set that threshold at about 3 months, and now he pushes that threshold back to two months.
And what he's doing at that point is plenectomy.And so splenectomy is a second or third line treatment for autoimmune hemolytic anemia in humans when they're refractory to immune suppression or IVIG or whatever treatment option they have been through.
And the many of those refractory or relapsing cases standard to respond to splenectomy, they just use that as a last line because it's an invasive procedure and you're, you know, really affecting the immune system a lot by removing that large organ.But in our experience, Pima dogs that are refractory to treatment or relapsing often have excellent response with splenectomy.
They will respond after just a few weeks.And that's not my experience.I'm just trying to relay what Doctor Chuckowitz said yesterday.But he did communicate to us that when when he started doing the splenectomies, he still felt a little insecure stopping pred at that point.
So he would have splenectomize and keep doing pred and only wean off once the animal was responding or resolved.But at now that he feels more comfortable and he understands the disease better, he will splenectomize and stop bread right there and those dogs will respond and be fine after a few weeks.
So then why not splenectomize earlier?Why do we have to wait until they fail?We have data, I suppose to know and it you know, splenectomy in and of itself is not a benign.Thing right?And most dogs respond to Prednisone, so why put them through a procedure that is invasive and is really affecting their immune immunologic equilibrium in the body?
So if you don't have to remove the spleen, don't.But then before we move out of this topic, I just wanted to comment.I hear a lot of people ask me, oh, but the spleen can be very erythropoietic in Pima.And if the bone marrow is failing to put the cells out, it's really a problem to remove the spleen because the spleen is making those cells to keep the dog alive.
So I don't want to remove the spleen and that only chance that the animal has to get red blood cells.And I disagree with that thought.I think that the spleen does have a potentially potential that has the potential to be a helpful organ because it does really pick up the hematopoietic function in the face of anemia.
However, the detrimental role of the spleen is much bigger than.That to me because I always thought the spleen was important there now much because that kind of with the real blood cells are being destroyed.Exactly.So yeah.But in Pima that those cells aren't even getting to the spleen.How's the spleen playing a role in destroying cells in the bone marrow?
So, so we have in the mechanistic studies look at the spleen.So what I'm going to share with you is what I understand from my MHA and immunology and, and some hypothesis, but some ideas are the spleen is a major immunologic organ and it is home to a lot of lymphocytes and a lot of the immune reaction in producing antibodies or sensitizing lymphocytes to be producing antibodies.
Or or if there is, and I don't know that, but potentially other known antibody related mechanisms to Pima like cell direct cell to cell destruction with cytotoxic T cells or whatever other parts of the immune system there are in that disease.
The the spleen is a major organ supporting all that immune mediator response.The spleen is also home to a lot of resident splenic macrophages that are very active in destroying the precursor similar to the destruction they do in IMHA like you mentioned.
So I think at the end of the day, the spleen ends up being more detrimental than helpful to the disease.So there's a war against the precursor cells, and the spleen is the military base that the soldiers are being sent from.So you're going from the military base A.Friend or foe kind of thing, because the spleen is also making a lot of those cells.
And so I understand when people come to me with that question, but but I think that if you have that immunologic part in mind also you see that it's more detrimental than helpful.And I think for me, if there's persistent spherocytosis, that gives me a little bit more evidence.
And again, it's anecdotal, but more evidence that splenectomy is going to be helpful.And I might splenectomies them early, earlier than one month, two months if they're a Pima case, but they have ongoing spherocytes.So the Pima cases get spherocytes as well.And 99% of the time, no, most of the time, I mean, I don't.
So I'm also very cognizant of geographical differences because I'm from Brazil and I understand there infectious diseases is a very big problem.And then we can get into the very nebulous thought of a secondary Pima.I can't comment on that.
OK.I don't have experience with that because I live in Michigan.It's a very clean, infectious, you know, clean cold place without infectious diseases for the most part.So I have a very little experience with that.But but yeah, I do understand there's geographical differences and perhaps Pima plus IMHA is more common in other parts of the world compared to Michigan, but I'm not sure about that.
But I really wanted to two things.I wanted to commend you for your instruction and the teaching role of teaching people to do bone marrows, encouraging people to do bone marrows.And then in tandem with that, I really wanted to stress that it can become detrimental to the patient and the owner to be treating a disease empirically, especially if it's a disease that is going to last for so long, take so much money on transfusions and potentially cause side effects from in long term immune suppression.
So I always, as much as I can, I try to inform people to please, please try as much as you can to have a clear solid bone marrow based diagnosis before you enter the road of a long term treatment.
So a couple of questions on that, practical questions A.So Clegg, it's the case, I've already put it on Preds taking a bone marrow aspirate on that, is that going to affect your reading of the bone marrow sample if it's already been on anemia suppressant for a week or so?My clinical experience is no, these Pima cases that they come to me because they're not fixed.
And when they're not fixed or despite being on bread, they're still going to have hyperplastic bone marrow with maturation arrest and erythrophagocytosis.And my clinical pathologist is still going to feel comfortable to say in combination with my CBC data and the bone marrow that this is precursor targeted IMHA.
Agreed Cydia.I, I will just because I'm a purist, I will just change that to precursor targeted immune mediated anemia and I remove the H, remove the H from there because there's no hemolysis in the majority of the case.And then the one last thing I really wanted to touch on is make sure you're familiar with how your pathologist is operating and looking at your slides because if first of all, you can make a diagnosis of Pima without seeing phagocytosis of the precursors, OK, the phagocytosis of the precursor is the cherry on top of the ice cream that adds that last piece of evidence.
But we have and we can make the diagnosis of Pima based on the clinical picture, the CBC data and the bone marrow patterns without seeing the phagocytosis.The fibrocytosis does add evidence and it's a nice thing to find and we do find that in about 90% of our cases.
But in tandem with that, I also wanted to highlight that for people that are sending bone marrow in the DTA in a tube to the lab and the lab is making their own smears, those cells start being fabricized in the tube during transport as little as 15 minutes after collection.
So, so, so if you care about the phagocytosis and if that is going to make a difference in your interpretation, be sure to be looking only at smears that were made at bedside with fresh material without sitting for any extended any period of time.
I can't even say extend any period of time has to be collected and made freshly.And that's the only slide you're going to look for phagocytosis.Like I said, talk us through our process space.Ninja marrow, bone marrowing skills?Yeah, absolutely.So of course you know, you've done the owner preparation in terms of making sure that they consent to a quick anaesthetic.
The patient is stable, you know, if it needed a transfusion, maybe it has a transfusion before or rather than when it's PCV is 7%.So I've, I've bone marrowed from lots of different bones, humerus, femur, ileum, sternum.I find the humorous easiest to teach.
So I am right-handed.I have the patient pre medded anaesthetized line, right lateral recumbency clip and prep over the proximal humerus sort of centering your clip.Yeah, over the proximal humerus.At the shoulder.Yeah, at the shoulder.
So I'm going to use the shoulder joint as a landmark.So dogs in lateral recumbency.I identify my site by palpation and I will put a little bit of lignacaine in at that site because the anaesthetic is so quick.I do want to have a little bit of local anaesthetic.
There skip or.Exit into the subcutaneous tissue.I actually put my needle down to touch the bone and put a blab there.A small blab.I use a size 11 or size 15 scalpel blade to make an incision through the skin and then I use an Illinois bone marrow needle to collect my liquid bone marrow sample.
I find them the best needles.We're usually using an 18 gauge bone marrow needle, although you can use bigger ones for bigger dogs if you want to.Most importantly is positioning for me so I'm right-handed.I use my left hand to grab the elbow joint and I use that to externally rotate the entire thoracic limb.
What that does is it takes, we should do a video of this.It takes the humerus and it basically points the long axis of the humerus towards the ceiling.And what it does is that the biceps muscle moves chordally and laterally and it exposes a little spot on the humerus.
It probably has an anatomic name, but I don't know what it is.A little flat spot just to the chordal aspect of the mid line of the humerus.And that little flat spot is lovely because the biceps muscle is moved quarterly.So basically there's skin, a tiny bit of subcutaneous tissue, and bone.
There's nothing dangerous in between and I've identified my shoulder joint dorsal to where my bone marrow site is to make sure I.Don't.So don't go to cartilage.Exactly or aspirates.I know of your fluid.That's not my intention in this procedure.So I'm using my left hand.
I'm externally rotating.So you've got the elbow in your hand.Elbow is going towards the table or or staying in the same.Plane externally rotated.The pore is coming up.The pore is coming up and the ulnar olecranon is going to be facing down towards the table.
Yep, gotcha.So I've got my bone externally rotated.I am going through my little releasing incision that I've made in the skin at my sight with my scalpel blade so that the bone marrow needle touches the bone through the skin incision and that my bone marrow needle is perpendicular, sort of up and down, roof and floor.
And then I rotate from my elbow, rotating downwards, holding the bone marrow needle like a gun with my index finger down towards the skin so that I've got direct control of my bone marrow needle.I rotate from my elbow to go through the bone cortex, which takes some force pushing down towards the table while I'm externally rotating.
And then when you go into the marrow cavity, you feel a bit of a release of pressure there.I stop.I remove the stylet.I attach my syringe, which is preloaded with some EDTA as an anticoagulant.I aspirate liquid bone.How much do you get syringe?How much?You can take almost an endless amount.
The marrow cavity, you know, it's continuous with the blood.Yeah.So you don't know hemodiluted so much, but I would add, so the procedure we use is similar to that.We do use half an ML of EDTA, that is if I am not wrong 3% concentration.
So it can't be.So EDTA we collect for blood is 10% EDTA.So bone marrow is very, very sensitive and the cells freak out if the EDTA is too high concentration.So we use 3% DTA, half an ML.A stash of it in a drawer with all of our bone marrow.
And we collect up to about 1ML in that half an ML of a DTA and then another ML of bone marrow and that's more than enough and.Then you smear some like a like a blood smear.And then do you put that in a Petri dish?I don't, you don't, but I think the Petri dish method is probably preferred by our clinical pathology.
Yeah, We put it on a Petri dish.The hospital has disposable Petri dish.So just put it on the Petri dish and then you grab like a little pipette or microhematocrit tubes and you pick up specifically just the bone marrow particles.So you just the picoles?The Jelly Jelly.But it's not.The the little grains of salt or sand because you want to minimize as much as possible hemodilution from just that blood of the the sinusoids and the blood vessels that ruptures inside the marrow.
You don't want that because that's gonna affect your MU ratio reading and so you want to have only the bone marrow particles if possible.I do it slightly differently.I don't know if it's as valid, but I use a kidney dish to set my slides up vertically.So when I put a drop of the liquid bone marrow on it, the blood runs down off the slide and the solid bits of marrow stick to the slide and then I use that.
And the squash mirror.I do an impression type which our clinical pathologist find useful as long as I let the blood what?Do you mean by an impression you're just like the touch and lift?No, I just go.Like a squash?Yeah.Like a squash, Yeah.Squash.Yeah, yeah, yeah, yeah.
And then how often do you do cores with your aspirates?So that's another conversation I love to have.So I was always taught that you should always get a call.Yes, yes, my so then we'll just stop there.What I do now though is a little bit different because I realize that veterinarians having to collect pores in practice detracts them from doing a bone marrow at all and so.
Is it so intimidating or is it so intimidating or the fact the chance of breaking a bone or what?I think they're intimidated by how much more force you have to use to get a core than to get an aspirant.So.We should all be going to the gym.We should all be to be, you know, fit and strong.
We should be able to help our patients.Yes, right.Sometimes they using a gem Sheedy that's too big and so that's part of the reason or too blunt because the needle needs to be sharp.But I found that sometimes that was detracting from people doing them.So I would rather that people do an aspirate than nothing.
And a lot of the time the core, you know, it's a, it's a cat with multiple myeloma and the core isn't necessary for the diagnosis and it gives us information, but it's not necessary for the diagnosis.The oncologist who I pre talked to and I say, I think this cat has multiple myeloma may not change his decision based on a core.
And so I will just collect an aspirin, confirm his multiple myeloma.He will start immune suppression.And, you know, three years later, the cat's still happily living with its multiple myeloma on effective chemotherapy.I think you hit the nail on the head there that usually the cases where an aspirin is sufficient are usually going to be our oncology cases.
We have the same in our hospital.But if it's the type of internal medicine emergency where you're not really thinking of bone marrow neoplasia, but you're thinking more of the non neoplastic conditions, then a core can be very helpful because the core has advantages that the cytology doesn't.
And honestly they complement each other.So I love your point of view of it's better to do the aspirin than do nothing.But if we can help people feel more comfortable doing the cord, I would also go for that.And one of the reasons for that is in, in the realms of Pima, for example, for to illustrate, about half of the Pima cases will have myelofibrosis ranging from mild to severe myelofibrosis.
We're not sure what the pathogenesis of the myelofibrosis is, but it's very common.And the most of the time when there's fibrosis, your bone marrow aspirate will be a dry tap with no particles.And there's still some findings that a pathologist can find even on a dry tap to have high suspicion of Pima.
You can see an erythroid predominance even among the blood contamination.You can see a left shift or maturation arrest.You can see the phagocytosis, but it's really hard even for me to be OK.This is 100% pema on the dry tap.I can have a high degree of suspicion, but it's hard to be definitive.
And it's getting that bone marrow core that will help you be definitive because it will have the rest of the pattern that will help you make that diagnosis.And then in conjunction with this thought, in the past myelofibrosis has been its own stand alone diagnosis.
And once you see it, you stop there.As a pathologist, I strongly discourage that in my experience.So there's something in humans that has been described, described as idiopathic myelofibrosis.That is not something that I have ever seen in a small animal.
If there's fibrosis, there's something behind it.In dogs, the vast majority of time when there's fibrosis, there's Pima.So don't let your pathologist stop at the diagnosis of fibrosis.Don't accept that.Push them further and have them see what else is there that you can still.
Treat that.You can still treat.Thank you for that question.Because in our Pima cases, so half of the Pima cases have fibrosis, most of the canine fibrosis cases are Pima.Very rarely it's neoplasia or iron deficiency, which doesn't warrant the bone marrow to begin with.
So the majority of the myelofibrosis cases in dogs are Pima.The minuscule minority is hematopoietic neoplasia and in our experience, Pima dogs with and without myelofibrosis had a similar response to treatment and prognosis and survival.
So we extremely, very strongly discourage clinical pessimism if there is fibrosis.So in the past it's been a thought process of fibrosis carries a bad prognosis, let's just euthanize.We very strongly discourage that because we've seen Pima dogs with fibro, different levels of fibro, degrees of fibrosis that respond and live a happy life for years, no problem.
With the wrap.That's amazing.I'm so glad I had you.And that's such a great topic.It opens a whole, I don't often do things anymore where I'm like, oh, but this is all new to me.And then it's so lovely because my business get the same experience of going, OK, there's a whole new world that we have to pay attention to.And again, even if you don't do it yourself, don't do the names refer.
There's potential treatment options.And I think for the GP, you know, starting with Prednisone, like you said, I start Prednisone, send it to you like we don't have a problem with that.I think the main educational piece here for the GP is keep refining the understanding of when is a bone marrow needed, When do I need to send this patient to someone that feels comfortable doing bone marrow so we can have a solid diagnosis before this animal is on treatment potentially for the next many months.
So thank you so much for having me.This is lovely.

Prof Cynthia Lucidi

Dr Claire Sharp