Equine Med- Hemolymphatic 1

drraythe's version from 2016-04-29 15:32


Question Answer
clinical signs of vasculitis in general?Edema (localized, limb or ventral), Petechial hemorrhages, Variable systemic manifestations
what are some infectious agents or dzs which commonly cause vasculitis?EIA Virus, Equine Granulocytic Erlichiosis, Equine Viral Arteritis, Purpura hemmorhagica
CSs of anemia depends on what?Is it acute or chronic?? ACUTE: weak, pale or icteric, tachycardic, tachypneic. signs of shock. CHRONIC: might not show signs at all till PCV <12%, poor performance
in chronic anemia, might not see any signs until PCV is...<12%
3 main mechanisms of anemia?Loss, Lysis, dec production
3 toxic (1 is drug) agents which can cause oxidative hemolysis?Onion, red maple leaf (when they fall to ground and wilt), Phenothiazines (such as acepromazine)
4 infectious agents which can cause hemolysis?EIA, piroplasmosis, Clostridium perfringens, Strep equi
4 immune mediated problems which can cause hemolysis?IMHA, neoplasia, drug reaction, neonatal isoerythrolysis if a foal
3 situations where anemia can be due to dec production?iron deficiency, chronic dz, bone marrow dz
inc in MCH means?hlysis (bc more hgb just floating around in blood)
when does MCV dec?iron deficiency
**how do you know if the horse has a regenerative anemia?Horses show no peripheral signs of regeneration!!! Will need Serial PCVs or bone marrow. FIND THE CAUSE.
how much blood can a horse lose and not die? 1/3 of their blood volume without death (10-12L)
what is a built-in mechanism to help protect PCV from hge? Catecholamine release → Spleen releases RBCs –Replaces 1 st 20% of loss
how long does it take before you see signs of blood loss in the CBC? What is the change you see?Redistribution of interstitial fluid into the vasculature → ↓PCV/TP
how can you differentiate intravascular vs extravascular hemolysis?Intravascular: hemoglobinemia (red plasma) +/- hemoglobinuria. With extravascular, the plasma will prolly only be icteric (bc wont have Hgb in blood but excess heme will be released) can be kinda hard to tell intra vs extra vascular apart but basically same tests and tx anyway so doesnt matter too much
if the anemia is is due to dec production, how severe the the anemia usually? Generally mild anemia - >20% generally (if PCV is <20, loss due to dec production goes way down on her list)
What will indices look like with Fe deficiency?Microcytic, hypochromic
if there is anemia due to bone morrow dz, you can feel more confident it's BM dz if you see...pancytopenia
markers of infection/inflammation for ACUTE dz?Neutropenia (left shift, toxic changes)...depends a lot of the dz process.
markers of infection/inflammation for CHRONIC dz?mild anemia >20%. leukocytosis (mature neutrophilia), Hyperfibrinogenemia, thrombocytosis, hyperglobulinemia
when do you wanna decide to do a BM eval?This is invasive, so so really only reserve for select cases where you have RO all you can (non regen and everything comes back neg) or you see there is pancytopenia.
what are the 2 types of BM evals? Aspirates and core biopsies
what are the 3 main areas you take a BM sample from?FLAT BONES! Sternum (most common), tuber coxae, proximal ribs (usually from sternum. You need a LOT of force to shove jamshedi in...and heart is veryyyy close. be careful. )
So you take your BM sample-- what are the 2 things which would tell you that there IS regeneration (since you know that there are no peripheral signs of regen in horses so BM would show you the way)(1) >5% reticulocytes (2) M:E ratio < 0.5
what % retics in the BM sample would indicate to you there is regen?>5% retics
the M:E ratio (Myeloid:erythroid ratio) would be what in your BM sample that would allow you to believe there is regen?<0.5 (which means that there is more than double the erythroid cells as compared to the myeloid cells)
what can you see when you look at the blood which would hint the anemia might be due to oxidative damage? (and exs of what causes oxidative damage)heinz bodies (think onion/kale/red maple leaf/phenothiazines)
if there is methemoglobinemia what mechanism of anemia might you suspect?oxidative damage
how might you go about dx EIA if you suspect infectious cause of hlysis?Coggins! (AGID or ELISA)
what are the two types of immune mediated hemolytic anemia?(1) Primary (idiopathic)= Abs made directly against RBCs. (2) SECONDARY: Indirect Abs to antigens coat the RBCs. Severe infection, neoplasia, drug rxn (penicillin and bute)
what are some thing that will trigger a secondary-type immune mediated hemolytic anemia?Severe infection, neoplasia, drug rxn (penicillin and bute)
what will lab results look like with immune mediated hemolytic anemia?Increased MCH, MCHC (regenerating), Erythrophagocytosis and autoagglutination, spherocytes
how do you dx EIA? how do you dx IMHA?DONT MIX THESE UP. Coggins with EIA. Coombs with IMHA (A horse named coggins-- and Abs on RBCs look like "combs")
2 tests to dx IMHA (and how they work- which is more specific and quantative?)(1) Coombs: Detect anti-RBC antibodies on the RBC membrane (2) Direct immunoflourescence with flow cytometry: Tests class of antibody bound to rbcs , More specific and quantitative
which two drugs are most likely to cause a 2* IMHA?penicillin, bute (Phenylbutazone)
if you wanna immunosuppress with steroids for IMHA, which steroids, and when should you start tapering?consider Dexamethasone, Prednisolone. First wanna stabalize PCV to 20% before tapering
how do you tx IMHA?USUALLY it is secondary (triggered from infection or drugs or sthing) so (1) Discontinue suspect medications (penicillin, bute) (2) If not infection/neoplasia: (a) Corticosteroids (Dexamethasone, Prednisolone) at immunosuppressive doses (dont taper till PCV stable at 20%) (b) other immunosuppressants: Azathioprine, Cyclophosphamide (3) Blood transfusion – if severe and life threatening – CROSS MATCH!
what are the two situations where iron deficiency anemia can occur?(1) Chronic blood loss (2) Dietary deficiency
where is most iron in the body?2/3 in RBCs
why are foals more prone to dietary deficiency of iron leading to iron deficiency anemia? Limited storage, Increased demand with growth, low Fe in mares milk, common in foals that are stalled
how severe will an anemia be with an anemia of chronic dz?mild to moderate-- PCV will be >20%!!!
what is the pathogenesis of anemia of chronic dz?Multifactorial! Decreased erythropoiesis, Decreased RBC survival, Decreased iron availability
what will bone marrow iron be like in iron deficiency anemia versus chronic dz anemia?Iron deficiency it will be low, but in chronic dz it will actually be increased (since it is sequestered)
how do you treat iron deficiency anemia (drug, route, how quickly does it work, downsides? Other drug?)ferrous sulfate, orally, you will see an improvement in lethargy quickly and the anemia will improve over weeks. However this is a gastric irritatant!! The other option is IRON DEXTRAN which YOU DO NOT GIVE PARENTERALLY (only oral supplementation)
what happens in red maple toxicosis? (what clinical probs do you see with it)pathophys not totally understood. gallic acid (strong oxidant) in the wilted leaves. hemolysis and enhanced methemoglobin formation
if a horse has red maple toxicosis, what drugs should you NOT give?Steroids


Question Answer
when do you know to transfuse or not?there isnt a specific PCV cutoff- often depends on the chronicity of the blood loss. Generally speaking, if there are symptoms of systemic effects, then consider transfusion.
(not sure if we need to know) equation for transfusion amount? When is this equation accurate?[ (Desired PCV-Patient PCV) x (0.08 x BW kg )] / Donor PCV .... Only accurate if chronic or fluid resuscitated
if a patient loses a bunch of blood and you wanna do a transfusion, replacing what % of the blood loss is sufficient? Replacing 30-40% of blood loss is sufficient (2-3 mL whole blood/kg → ↑ patient PCV 1%)
**how much of the donor blood volume are you taking?Donor: 20-25% of blood volume
how many blood groups do equines have/ how are they named8 blood groups: A,C,D,K, P, Q, U and T and then there are 32 factors (little letters next to capitol, like Aa)
The best equine blood donors lack which blood types? Which breeds are these usually?Best equine donors lack ***Aa, Qa,****** Ae, Ca. Usually Standardbred, QH, Morgan geldings
So youre out on the farm and don't have all that fancy blood typing equipment with you but this horse is dying and need blood stat. Who is your best donor?PREVIOUSLY UNTRANSFUSED GELDING (normal PCV) (a mare might have been exposed to foal blood before, you never know)
when must you cross match blood?for first transfusion a match is recommended, but for the second it is REQUIRED. (prolly wont have Abs on first go but by second def will)
what is a Major agglutination test? Minor?MAJOR: DONOR rbcs with the RECIPIENT SERUM (makes sense-- these are the things we care about.The donor RBCs we need and its the recipient's plasma with the Abs we'd be worried about). MINOR: Recipient's RBCs with the donors serum
what are the major transfusion reaction problems we are worried about?anaphylaxis (think nasal swelling with an obligate nasal breather), severe agglutination