Immunology/haematology Flashcards
Cyclophosphamide mechanism of action?
Alkylation (cross linking) of DNA in S phase.
T and B cell lymphopenia, suppresses T cell activity and AB production
Acrolein bladder tox.
Azathioprine mechanism of action?
Purine analogue, metabolised to ribonucleotide monophosphates (6mercaptopurine) and inhibits enzymes required for purine biosynthesis. DNA incorporation causes RNA miscoding.
Humoral > cell mediated immunity. Decreases lymphocyte activation and proliferation (lack of purine salvage pathway). Decreases macrophage function.
Active form metabolised by thiopurine methyltransferase and xanthine oxidase.
Relevant breeds and medications for azathioprine use?
Giant schnauzer/cat - low TPMT activity. Malamute - high TPMT activity. Allopurinol inhibits XO.
Methotrexate mechanism of action?
Inhibits (competitive) folic acid reductase - no purine/pyrimidine synthesis. Mostly S phase.
Glucocorticoid mechanism of action?
Cytosolic glucocorticoid receptors (vary with tissue), glucocorticoid response elements, gene transcription.
Stabilise endothelial membranes, decrease chemotactic factors/cytokines/adhesion molecules. Inhibit arachidonic acid release.
Dose dependent, cellular/humoral.
Decrease pro inflamm cytokines, complement function, T cell proliferation/AB production, macrophage Fc receptors
Increase anti inflamm cytokines
Redistribute mono/lymphocytes, mainly T, to bone marrow and lymphatics.
How much mineralocorticoid activity do the various steroids have in comparison to cortisol?
Prednisolone 0.3 - 0.8
Dex 0
Hydrocortisone 0.8 - 1
Cyclosporin mechanism of action?
Cyclosporin/cyclophilin compleex binds and inhibits calcineurin. Impedes calcium dependent signal transduction/dephosphorylation, impedes activation of nuclear factors of activated T cells. No nuclear transcription of IL2 so decreased T cell activation/proliferation.
Cytotoxic T cell activity decreased.
Stimulates TGFbeta production which inhibits IL2-stimulated T cell proliferation and generation of antigen-spec cytotoxic T cells.
NB need ultramicronised microemulsion (better absorption)
Cytochrome p450 metab, biliary excretion. Peak conc 2h
Pharmacodynamic evaluation measures IL2 and IFN gamma.
Hepato-nephrotixicity v uncommon
Side effects of ciclosporin?
Secondary inf gingival hyperplasia hirsutism
Tacrolimus mechanisms of action?
Similar to cyclosporin - FKbinding protein complex, decrease T cell activation.
Does B and T cells and ABs. More potent than cyclosporin.
Mechanisms of action of sirolimus/rapamycin?
mTOR inhibition
(T cell G1 - S, cyclosporin G0 - G1)
T and B cells
Mechanism of action mycofenolate?
Hydrolysed to mycophenolic acid by the liver (active form).
Inhibits inosine monophosphate dehydrogenase in activated lymphocytes (needed for de novo purine biosynthesis). Prevents guanosine and deoxyguanosine biosynthesis.
Inh B and T cell proliferation. Decrease AB production. Apoptosis activated T cells. Humoral and cell med immunity, decrease adhesion and lymphocyte/mono recruitment
Hepatic glucuronidation inactivates to mycophenolic acid glucuronide which is excreted in bile (intestine flora deglucuronidate so get second peak). 90 % excreted in urine as MPAG.
Leflunomide mechanism of action?
Inhibit de novo PYRAMIDINE synthesis. Dihydroorotate dehydrogenase inhibitor.
B and T lymphocyte - decrease proliferation, decrease leucocyte adhesion, decrease IgG synth.
Activates by intestinal mucosa/liver to teriflunomide.
Renal excretion of trimethylfluoroanaline - susceptible tox if renal insufficiency.
Chlorambucil mechanism of action?
Non cell cycle specific alkylating agent. Cross links DNA. Inhibits resting/dividing cells, esp lymphocytes - cell and humeral immunity inhibition.
Inactivated by the liver
How are RBCs destroyed in extravascular/intravascular haemolysis?
Extra - macrophages in spleen
Intra - complement mediated - IgM ABs activate
Antierythrocyte ABs from B cells, but T cell (CD4 driven disease)
What genetic factors are there for development of IMHA?
Breed - cocker spaniel, familial association
Autoreactive T cells in siblings
DLA haplotype?
Most common antigen in IMHA?
Anion exchange molecule/erythrocyte membrane glycoproteins
What seasons is IMHA most common in?
Spring and early summer
Percentage of idiopathic IMHA?
70 - 80 %
What antibodies are most common canine IMHA?
IgG or IgG plus IgM (rare to have only IgM)
Increased pro-inflamm cytokines IMHA?
Monocyte chemoattractant protein 1, GMCSF (assoc with mortality also IL15 and 18)
Why might thromboembolism occur in IMHA?
DIC - evidence present 50 %
What do platelets express more of in IMHA?
P-selectin - activation (driven by cytokines)
Negative prognostic indicators canine IMHA?
Hyperbilirubinemia, thrombocytopenia, leucotyosis with left shift, azotaemia, hypoalbuminaemia, intravascular haemolysis, prolonged hyperlactataemia hepatic insufficiency, macrophage activating cytokines, autoagglutination, increased aPT.
What is NOT associated with IMHA outcome?
Degree of anaemia, magnitude reticulocyte response (1/3 present non-reg), degree of spherocytosis
Why would you use LMW and not unfractionated heparin?
Latter more likely to cause iatrogenic coagulopathy (thrombin and Xa). LMW less protein bound and more stable pharmacokinetic.
Mechanism of heparin action?
Binds AT, enhances its activity, inhibit factor II and X. CRI required for efficacy?
LMW only does Xa not thrombin. Need to monitor this factor to assess efficacy, can’t use aPTT.
Variable between individuals, goal appt 1.5 - 2.5 x RI
Does ultralow dose aspirin have an anticoagulant effect?
Not in healthy dogs. Single 5 - 10 mg/kg dose inhibits platelet function in healthy dogs.
BUT ultralowdose aspirin was associated with improved outcome in dogs with IMHA.
Clopidogrel target?
Platelet P2Y12 (ADP receptor) - block aggregation
Survival benefit of aspirin versus clopidogrel IMHA?
No difference, even if clopidogrel loaded. No difference if drugs added together.
Benefits of glucocorticoids in IMHA?
Suppress macrophage function
Decrease T cell activity (therefore decrease B cell stim and AB production) and induce lymphocyte apoptosis
Evidence for secondary immunosuppressive drugs in IMHA?
One study found superior survival with azathioprine, otherwise no evidence to add secondary
Platelet count in greyhounds?
Can be lower than other breeds
In what infectious diseases have anti platelet antibodies been detected?
Ehrlichia canis, Rickettsia. rickettsii (RMSF), A phagocytophilum, Babesia, Lepto, Leishmania
Most likely causes of moderate to severe thrombocytopenia?
ITP, overwhelming sepsis, E canis
RBC life span in cats and dogs?
70/120 days
Indirect/direct platelet autoantibody?
Indirect - AB in serum, direct - AB on platelet/megakaryocyte surface
Direct more specific
When is splenectomy contraindicated in ITP?
Haemoparasite infections - can exacerbate and associated with resistance antiprotozoal therapies.
ITP negative prognostic indicators?
Severe bleeding with anaemia, intracranial haemorrhage, melaena/increased urea
NOT platelet count
Most common antigen in ITP?
Fibrinogen receptor (GPIIb/IIIa)
Decrease in Treg cells implicated
ITP associated with recent vaccination?
NO!
one case report distemper
What Ig is on platelet in ITP?
IgG (present in 77 % ITP, 100 % B gibsoni…)
Increases with age of sample
Evidence for secondary therapies in ITP?
IVIg and vinc equally shorten time to platelet recovery and hospitalisation
One case series mycophenolate mono therapy
No evidence for other secondary agents
Platelet decrease significance in IMHA?
< 50, 76 % mortality 30 d
< 15, 25 % mortality (not different IMHA alone)
Cats and IMT?
Only around half respond to pred alone - need secondary. Frequent relapse. Long term immunosuppressive.
What influences BMBT other than platelet number and function?
Haematocrit, blood viscosity
What PFA time is best for vWD?
Collagen/ADP, > 120 s
Also impacted by BMBT factors
What % of vWF is normal?
70 - 180 %, < 50 abnormal
What might falsely increase and decrease vWF?
Decrease - haemolysis
Increase - pregnancy/parturition/inflammation/sepsis
Type 1 vWD?
Partial quantitative deficiency - Doberman, Irish setter. GSD, BMD - all same mutation, autosomal recessive
Type 2 (A) vWD?
GSH/WHP, collie, Chinese crested Auto recessive
Loss HMW protein, need to demonstrate decrease collagen binding activity (ratio with Ag:binding >1)
Type 3 vWD
Complete lack of factor. Dutch koiker, scottie, sheltie.
Auto recessive, various mutations
Inheritance pattern of congenital coagulation factor deficiencies?
Haemophilia A and B (8 and 9) X linked recessive
I, II autosomal
VII, X, XI, XII autosomal recessive
Changes in clotting times with coagulation factor deficiency?
PTT and PT: I, II, X
PT: VII
PTT: VIII, IX, XI, XII
Do dogs have vWF in their platelets?
No, only endothelium
Does factor activity influence clinical severity in canine type 1 vWD?
Controversial - one source says yes one says no
What haemophilia is most common? What haemophilias affect breed/species?
Dogs and cats. A most common. Many breeds.
What percentage of factor activity correlates with most bleeding in haemophilia?
Severe < 2 %, mild to moderate 2 - 20 %
Normal = 50 - 150
Breeds for congenital factor I deficiency?
Fibrinogen - dogs (borzoi, collie, bichon) and cats
Breeds for congenital factor VII deficiency?
Initiates coagulation by interacting with tissue factor.
Beagles, deerhounds (same mutation) - mild.
More severe malamutes and cats.
Breeds for congenital factor XI deficiency?
Kerry blue, springer, cats
Mild haemorrhage
Breeds for congenital factor XII deficiency?
Haegman. Cat. Activates intrinsic pathway in vitro not required for fibrin formation in vivo. No clinical consequence.
What are the labile clotting factors?
V and VIII
What is in cryoprecipitate?
vWF, VIII, I, fibronectin, XIII
What is in cryosupernatant?
Everything but vWF, VIII and I
How does tranexamic acid work?
Antifibrinolytic. Lysine analogue, inhibit plasmin activation.
What is the main stimulus for thrombin formation in DIC?
Tissue factor:VIIa complex. Activates factor IX (intrinsic) and X (common pathway)
How might DIC occur in systemic inflammation?
Monocytes express tissuee factor, anticoagulant system impaired, PAI-1 (plasminogen activator inhibitor) mediated fibrinolysis inhibition,
What does antithrombin inactivate?
II, TF:VII, IX, X, XI
Also binds cellular receptors on neutrophils/monos, stim antiinflamm/antiplatelet prostacyclin production
AT depletion (consumption in AT thrombin complex, degradation by neutrophil elastase, decreased hepatic synthesis, loss due to capillary permeability) factor in DIC
When should DIC be anticipated
Hypotension, impaired organ blood flow, SIRS, vasoactive agent release
What is a sensitive test for DIC?
D - dimer - 95 % sensitive
How does the endothelium protect against thrombosis?
Thrombomodulin binds thrombin and allows it to activate protein C, C associates with S.
CS: inactivates V and XIII
Endothelium produces prostacyclin under thrombin influence - inhibits platelet aggregation.
Tissue plasminogen activator causes fibrinolysis.
How might fibrinogen change haemostasis?
Increased in inflammation. Increases blood viscosity and RBC aggregation - decreased blood flow. Increases velocity of platelet aggregation and increases platelet reactivity. Denser clots, more resistant to fibrinolysis.
Why might aspirin be ineffective in dogs?
Aspirin acts through decreasing thromboxane A2 formation and therefore increasing platelet activation for its lifetime. Thromboxane is G protein mediated and 70 % normal dogs have a defect in the G protein signalling.
High dose or low dose aspirin for ATE in cats?
Low dose is fine as no diff in recurrence, fewer GI effects
What factors might affect TEG/ROTEM?
Hypocoag - increased PCV/decreased platelet
Hypercoag - decreased PCV/increased fibrinogen, storage
How sensitive are PT/aPTT?
Need factor activity to be decreased by 30 - 50 % to be abnormal
What affects PT?
Tissue factor (extrinsic) and common pathways.
VII, X, V, II, I
What affects aPTT?
Contact (intrinsic) and common pathway.
VIII, IX, X, V, II, I.
What would you measure with the Clauss method?
Fibrinogen.
Could also measure with thrombin time.
What is the difference between FDP and D dimers?
D dimers are only present if there has been fibrin crosslinking.
D dimers have short half life approx 5h.
Why is thrombin antithrombin ELISA measurement useful?
Thrombin has a short half life, TAT stable. Increased HAC/neoplasia/blastomycosis.
Why are animals with IMHA hypercoagulable?
RBC membrane phosphatidylserine exposed.
Monocytes express tissue factor.
Systemic inflammatory state increased platelet reactivity.
What are most IMHA deaths causes by?
Thrombosis, pulmonary most common
Does albumin correlate with risk of thrombosis in PLN?
PLN - other factors for hypercoag other than AT - platelet reactivity/fibrinogen increase/fibrinolysis decrease.
Albumin might be a marker of thromboembolic risk but doesn’t always correlate with hyper coagulability and AT. Can be hypercoag with normal albumin.
14 - 27 % PLN get thrombosis
PLE and thrombosis?
Decreased AT and evidence of hypercoagulability. Clinical thrombosis low but unpredictable - can happen when improving.
What is the most common cause of PTE?
Neoplasia
What enzyme do anticoagulant rodenticides inhibit?
Vitamin K epoxide reductase (reduces vitamin K epoxide so it can act with gamma glutamyl carboxylase to carboxylate clotting factor precursors)
Vitamin K dependent clotting factors? One with shortest half life?
2, 7, 9, 10, protein C and S
7 shortest half life
When does PT change after rodenticide intox?
36 - 72h
PIVKA at 12h
What are acquired anticoagulants?
Antibodies directed against clotting factors, usually IgG.
Example - lupus anticoagulant - antiphospholipid protein AB - inhibits coag factor/cell membrane interaction - increased PTT
Scott syndrome?
GSD, lack of externalisation of phosphatidylserine - get coagulopathy as membrane surface cannot support plasma coagulation factor activity
Autosomal recessive.
Get epistaxis not petechia/ecchymoses. Prothrombinase activity required for nasal arterial microcirculation?
Flow cytometry can measure PS externalisation
How would the corrected reticulocyte count be calculated?
Divide retic count x hct by normal hct
How long does it take for a rbc precursor to develop through to RBC?
5-7d
How long do reticulocytes stay in the bone marrow for?
2-3d
What effect does EPO have on the cell red composition?
More retics and latestage polychromatophilic erythroblasts (normoblast)
What result would you expect from Coomb’s/osmotic fragility test in haemophagocytic syndrome?
Negative both
Why does hypophosphataemia cause haemolysis?
Decreased membrane stability (interference with energy metabolism), so more osmotic fragility and susceptibility to oxidative stress.
When would a Coomb’s test be positive in Babesia?
Gibsoni/vogeli
Most sensitive test for Babesia?
PCR
Retroviruses and mycoplasma?
Increased risk for mycoplasma
When do anti-erythrocyte antibodies develop in mycoplasma infection?
After the onset of anaemia
Pyruvate kinase deficiency?
Autosomal recessive, progressive iron overload might cause haemosiderosis/hepatic fibrosis.
Can occur in cats and dogs. Cats dx old dogs young.
DOGS - progressive myelofibrosis due to iron overload./prolonged haematopoiesis.
Phosphofructokinase deficiency?
Springer spaniels. Autosomal recessive. Not cats.
Exacerbated by exercise (alkalaemia - haemolytic crisis)
What markers are usual for histocytic sarcoma?
CD 11 and CD 18
Macrophage derived
Where is EPO made?
Peritubular interstitial cells under the influence of hypoxia inducible factor
Also liver - may be increased with hepatic injury
What might increase hepcidin?
Positive acute phase protein so IL6, also decreased renal clearance can increase
Transferrin?
Negative APP, TIBC
Iron deficiency saturation percentage?
Iron/TIBC < 20 %
What is important about EPO analogues?
Aim low end RI to minimise hypertension, have to give iron concurrently.
Darbo give less often, and less likely to form antiEPO ABs, but more expensive.
What hormones stimulate erythropoiesis?
T4, glucocorticoid, growth hormone
How should a polycythaemic dog with a concurrent PDA be managed?
PCV maintained higher due to hypoxaemia
GPIIIb/IIa?
Fibrinogen receptor
GPIb?
vWF receptor
GPVI?
Collegan receptor on platelet
Where is thromboxane A2 from?
Phospholipase A2 in platelet > arachidonic acid on activation > COX 1 makes into thromboxane A2
Alpha granules platelet?
Some vWF in cats, fibrinogen, factor V/XII, P selectin
Dense granules platelet?
ADP, calcium, serotonin
Does DDAVP increase HMW vWF?
Increases vWF a little in type 1 but not more HMW in dogs
Acquired vWD?
CKCS with mitral valve disease (decrease factor and loss HMW multimer),
Also SAS
vWD in cats?
Both type 3 in case reports
Greater Swiss mountain dog platelet disorder?
P2Y12 receptor - impairment of ADP binding.
Autosomal dominant. No spontaneous bleeding.
Glanzmann thrombasthenia?
Otterhound and Great Pyrenees, two different mutations, autosomal recessive.
Absence of the fibrinogen receptor (GPIIb/IIIa) - get spontaneous bleeding.
Also described in a male cat with integrin subunit alpha IIb gene mutation.
CaIDAGGEFI thrombopathia?
Prevents GPIIIb/IIa conformational change for fibrinogen binding. Spontaneous mucosal bleeding.
Basset, spitz, landseer. Recessive.
Cyclic haematopoiesis?
Grey collie. Autosomal recessive.
Cyclic neutropenia/stem cell deficit. Defect trafficking lysosomal membrane proteins. Neutrophils deficient in neutrophil elastase and myeloperoxidase.
Platelet storage pool disorder - serotonin/ATP/ADP deficiency (dense granules).
Cannot phosphorylate intracellular proteins so lack of platelet activation by collagen, thrombin etc.
LAD I/II?
GSD, impaired integrin activation on platelets.
Chediak Higashi syndrome?
Lack of dense granules in platelets.
Recurrent neutropenia with neutrophil function defects.
Leucocyte/melanocyte abnormalities. Persian (blue smoke). See abnormally fused granules in neut/eos/other cells.
C-GSF might partially correct neutrophil function.
Platelet delta storage pool disease?
Platelet dense granule ADP deficiency - Am cocker spaniel.
Increase ATP:ADP ratio in platelets.
What product is useful in Scott syndrome?
Cryopreserved platelets as they have externalised phosphatidylserine
What might look like Chediak Higashi syndrome on a blood smear?
Birman granulation anomaly, toxic neuts, mucopolysaccharidosis.
Pelger Huet anomaly?
No functional implications. Defective granulocyte maturation. Hyposegemented nuclei.
Autosomal dominant with incomplete penetrance (heterozygotes = embryonically lethal). Australian Shepard.
What might mimic Pelger Huet anomaly?
Inflammation/infection/myelodysplastic syndromes
Leucocyte. adhesion deficiency?
CD18 integrin deficiency - leucocyte adhesion protein mutation. Irish setter. Marked neutrophilia, susceptible to infection, die at 2-3m.
Trapped neutrophil syndrome?
Autosomal recessive, border collie.
BM myeloid hyperplasia with peripheral neutropenia.
Craniofacial deformities?
X linked severe combined immunodeficiency?
Cardigan corgi/basset
Mutation in IL2 gene. Affected developing lymphocytes (CD 4 and 8 neg) in the thymus. No T lymphocytes. Get non-functional and B over time.
Autosomal recessive combined immunodeficiency?
JRT, defective recombination events during T and B lymphocyte maturation. Decreased lymphocytes and globulin.
Common variable immunodeficiency?
CKCS/mini Dachs
P carini due to absence of B cells/decreased globulin
How might you diagnose immune mediated neutropenia?
Flow cytometry for anti-neutrophil ABs, is sensitive and specific.
Granulocyte agglutination and immunofluorescence is not sensitive or specific.
What bone marrow changes would suggest primary myelodysplastic syndrome over secondary dysmyelopoiesis?
Increased immature precursors, higher percentage of dysplastic cells, megaloblastic erythroid precursors.
Differentiate from chronic myeloid leukaemia as no circulating myeloid cell increase
NB secondary due to sepsis - increased blast in recovery)
MDS excess blasts?
Most common one in dogs and second most common in cats.
Pancytopenia, increase myeloblasts (up to 20 %) in bone marrow, dysplasia in all three cell lines, asynchronous maturation.
Many cat with this are FeLV pos.
Poor px
MDS refractory cytopenia
Older dogs, insidious onset, only red cells. Hyper or normocellular bone marrow, erythroid hyperplasia/dysplasia, rubriblasts may be up to 30 % of nucleated marrow cells.
In cats - other cell lines also affected (is this actually refractory cytopenia with multilineage dysplasia?
MDS refractory cytopenia with multilineage dysplasia?
Cats, FeLV, dysplasia two cell lines with < 5% myeloblasts
What causes secondary dysmyelopoiesis?
IMT, IMHA, PRCA, neoplasia
Chemo drugs, leishmaniasis, oestrogen
Secondary myelofibrosis?
PK deficiency most common.
Also necrosis, FeLV, drugs, toxins, rhEPO
Myelonecrosis?
Ischaemia, IMHA, sepsis, neoplasia, drugs
Lyophilised platelets?
Non-inferior to cryopreserved platelet concentrates. for management of bleeding in thrombocytopenic dogs.
What improves slide agg specificity for IMHA?
Dilution with saline, but sensitivity decreases. 1:1 29 % spec, 88 % sens
GSH, ROS and vit E in anaemia?
GSH decreased in anaemia, lower in non-haem than haemolytic, no diff ROS/vitE
Does pRBC transfusion affect TEG in dogs?
Only minimally. Decrease MA/clot strength
What affect would tranexamic acid have on TEG?
Increased MA, decreased percentage clot lysis
What blood group naturally occurring alloantibodies might dogs have?
DEA 3, 5 and 7
Mean platelet component in IMHA?
Lower and associated with mortality.
Prevalence of DEA 4 antigen?
> 90 %
Can RBCs be cryopreserved in glycerol?
No
Is clopidogrel generic equivalent to Plavix in cats?
Yes for plasma conc and active metabolite
Why would hypocobalaminaemia cause anaemia?
Decreased purine/thymidylate synthesis, impaired erythroblast DNA synthesis, erythroblast apoptosiss
Why are cats susceptible to Heinz body formation?
More oxidisable sulfhydryl groups, lower intrinsic antiox activity, lack of N-acetyltransferase 2 so paminophenol produced and methemoglobin production perpetuated.
Cat breeds reported for porphyria, erythrocyte osmotic fragility and PK deficiency?
Porphyria - Siamese, DSH
EOF - Abyssinian, DHS, Somali
PK - Abyssinian, Somali, Bengal
Punctate or aggregate retics relevant for assessing regeneration?
Aggregate (they mature to punctate in cats)
Cats with breed specific RI for Hct/retic count?
Birman, Norwegian forest cat and Siberian, Maine coone
RBC markers of iron deficiency?
MCV/MCHC, but insensitive - retic Hb content better
BM findings in PRCA?
Reduced/absent precursors.
Normocytic/normochromic anaemia. No other cytopenias.
BM in non reg IMHA?
Marked erythroid hyperplasia and low myeloid:erythroid ratio.
May be maturation arrest.
Often dysplasia/fibrosis/necrosis.
Circulating normo- or macrocytic (latter due to agglutination) RBCs, often neutropenia or decreased platelets.
Other criteria for dx:
Pos DAT/slide agg/ghost cells
BM in aplastic anaemia?
Reduction/absence of haematopoietic tissue with replacement by fat. Bi/pancytopenic.
When would you have secondary myelodysplastic syndrome?
Chemo or radiation.
What would a bone marrow increase in reticulin fibrosis indicate?
Myelofibrosis
What is menatetrenone and what might you use it for?
Vitamin K2 analogue, promotes cell differentiation, use feline MDS
What does vitamin D do to hepcidin?
Inhibits production
Prevalence of naturally occurring ABs against dog erythrocyte antigens in cats?
High prevalence based on major crossmatch
PFA100 in anticoagulant treatment in cats?
Detects changes in healthy cats treated with clopidogrel but not aspirin.
When is remission seen in non reg IMHA in cats?
Around 40 - 60 days. No difference outcome PRCA/NRIMHA. Remission reported with steroids alone, cyclosporin alone, steroids plus cyclosporin, steroids plus chlorambucil.
What happens to feline RBCss when you store them?
Haemolysis and ecchinocytosis
How would hyperfibrinolysis look on ROTEM?
Late, weak clot formation
What DEA antibodies do Cane Corsos have?
Anti-DEA 7
Rivaroxaban mechanism of action? How to monitor?
Xa inhibitor.
Monitor with PT and (peak reaction time) R value of TEG - aim 1.5 - 1.9 x
Agreement between D dimer assays?
Poor.
Does TEG predict thrombosis in dogs?
Not well.
How may you therapeutically induce Treg cells?
Low dose IL2 tx - Treg express IL2 receptor
Cyclophosphamide in IMHA tx?
Poorer outcome in two studies
Macrothrombocytopenia?
CKCS and Akita
What happens after xenotransfusion?
Haemolysis 1 - 6 d, haemolytic transfusion reaction (delayed) in 64 %
Crossmatching cats pre-transfusion?
Some studies say improved post transfusion increase in PCV. Incompatibilities frequent even in naive cats (15 %). Less febrile transfusion reactions in crossmatched cats.
This has not been consistently documented.
Older blood products may impact survival.
What inhibits fibrinolysis?
Tissue plasminogen activator inhibitor, alpha 2 antiplasmin and thrombin activatable fibrinolysis inhibitor
What does normal APTEM with increased clot lysis on EXTEM mean in terms of ROTEM?
Hyperfibrinolysis
Suggested mechanism for greyhound hyperfibrinolysis?
Decreased alpha2 antiplasmin
Angiostrongylus coagulopathy?
vWF deficiency, hyperfibrinolysis, DIC
Decreased fibrinogen/hyperfibrinolysis on ROTEM
Dirofilaria immitis coagulopathy?
Hyperfibrinolysis - directly stimulates plasmin production - hyperfibrinolysis
What happens when you add omega 3 to aspirin tx?
More inhibition of platelet function. no impact omega 3 alone
Which disease has lower platelet and WBC - Ehrlichia or leishmania?
Ehrlichia
Cyclosporine or mycophenolate for IMT in dogs?
Equal response - less SE myco
What happens to ammonia and lactate when you store pRBC? Glucose/Na/Cl/K?
Increased lactate/ammonia, increased sodium and chloride, decreased glucose and potassium
Comparison between dogs with amegakaryocytic thrombocytopenia and primary IMT?
Amegakaryocytic more severe and worse px
What does it indicate if anti platelet antibodies recur in IMT patients?
Increased risk of relapse. But persistence not associated with treatment response.
What pRBC are best for IMHA?
Fresh, no more than 7 - 10d as increasing age increases mortality/risk of transfusion reactions.
Response rate of pred alone in IMHA?
80 %, no evidence dexa superior
Evidence for secondary drug in IMHA?
Azathioprine might be assoc with better outcome - not uniform through studies
Ciclosporin - never any difference in survival found
Mycophenolate - compared to aza or ciclosporin - no difference
IVIG - no effect on survival compared to aza - but more rapid recovery of pcv or less transfusion requirement maybe?
When do hepatotoxicity and myelosuppression occur with azathioprine?
First few weeks hep, can be months BM.
GSD more susceptible hepatotoxic?
Ciclosporin liver effects?
Uncommon idiosyncratic hepatotoxicosis
When is thromboprophylaxis particularly important in IMHA?
Intravascular haemolysis, autoagglutination, marked leucocytosis, increased hepatic enzyme activity
Anticoagulant drugs for IMHA?
Longer survival if individual unfrac hep dose cf non-individualised
No diff clopidogrel versus rivaroxaban - latter better for fibrin rich venous thrombosis?
Canine familial methaemoglobinaemia?
Pomeranian, CYB5R3 mutation. this is the NADH cytochrome B5 reductase gene. Encodes methemoglobin reductase.
Probably recessive.
Treat with methylene blue.
(ascorbic acid/riboflavin?)
Other than IMHA, what might cause an abnormal osmotic fragility test?
Hyperlipidemia, age of erythrocyte, congenital membrane abnormalities
What can cause spherocytes other than IMHA?
Oxidative damage, hypersplenism, PK deficiency, erythrocyte fragmentation, spectrin deficiency (if > 24h old)
How many drops of saline should you add to blood for. slide agg?
4 drops - 100 % specific
Are tests for IMHA affected by transfusion?
Probably - DAT, spherocytosis and SAT
Criteria to support hyperbilirubinemia?
> 2 urine dipstick dog, icterus, increased in blood, any in urine cat
What Babesia species is most associated with IMHA?
Gibsoni most evidence
Also canis, rossi and vogeli
(Small > large)
Immunosuppression should not be required - due to damage to cell membranes/exposure of epitopes act as antigens
What infections cause DAT pos?
Leishmania, D immitus, Bartonella
Anaplasma cause IMHA?
Maybe - phagocytophilum and platys
Babesia and IMHA in cats?
Yes - B. felis, tx resolves without immune supp
Pathogenesis of mycoplasma and IMHA
Similar to Babesia
Babesia conradae?
California, coyote hunting dogs - no serological test available do PCR
What does FIBTEM measure?
Fibrinogen (Max clot firmness)
Clinical significance of methemoglobinemia?
Oxidation of ferrous iron to ferric iron, can’t bind O2, cyanosis and impaired aerobic resp. Causes allosteric interaction and left shift dissociation curve (decreased release O2)
How does NMB treat methemoglobinemia?
NADPH reductase converts to leukomethylene blue, which reduces methemoglobin to Hb
Cell free DNA in IMHA?
Neutrophil extracellular traps - might increase hypergoag
What breeds might be Dal negative?
Dalmation, doberman, Shih tzu
V prevalent in other breeds, might be hard to find Dal neg donor
No naturally occurring AB though, just post transfusion
What types of Kai positivity can dogs have?
Neg 1 and 2 or pos for 1 or 2. Pos 1 most common. Unrelated to Dal, 1, 3, 4 and 7
HCM Maine Coones and hypercoagulability?
A31P mutation in myosin binding protein C (MYBPC3) - increased P selectin, platelet derived microvesicle and platelet endothelial adhesion molecule 1 expression,
Clopidogrel attenuates in most but not all cats
What does cyclosporin do to thromboxane synthesis?
Increases - inhibited by aspirin
How might glanzmann thrombasthenia occur?
Defect in gene encoding GPIIb or GP IIIa - ONLY FORMER IN DOGS
Negative prognostic factors for IMHA in cats?
Increased bilirubin, age
Decreased globulin, lymphocyte
How might cyclosporin promote oncogenesis?
Promote angiogenesis, inhibit DNA repair and apoptosis, promote TGFbeta synthesis
How does IVIG work?
Modulate macrophage Fc receptors expression and function, decrease B/Tcell activation, interfere with complement action, decrease Ig production
What is the most common bacterial type to cause septic arthritis?
Gram positive aerobes
Infectious causes of polyarthritis?
Any Ehrlichia, Borrelia, Anaplasma phagocytophilum, R ricketsii, Mycoplasma, L form bacteria, leishmania
FeLV cat
Mycoplasma species and polyarthritis?
Cat felis/gatae, dog spumans
L form bacteria?
Lost cell wall, need special culture/electron microscopy
Subq abscesses in cats and dogs, and polyarthritis
Pathophys of fungal disease and joints?
Can be either direct involvement or secondary IMPA (latter more common)
Calicivirus vaccine?
Can cause short duration mononuclear joint inflammation in kittens
How would steroids affect mucinosis?
Decreased hyaluran synthase activity decrease hyaluronic acid in skin
Hypersensitivity in IMPA?
Type III - Ag/AB deposition
Ddx for IMPA?
Panosteitis, hypertrophic osteodystrophy
Criteria for IMPA diagnosis?
> 10 % neuts in >1 joint
How many IMPA fail to respond?
10 %
Do concurrent DEA 1.1 1.2 positive dogs exist?
No - but can negative for both
What group has Dal antigen commonly negative?
Dalmatian - paradoxic…
False positive DEA 1.1?
Weak 1.2, autoagglut
AB allele interaction with a and b?
AB recessive to A and codominant to b
What mutation to type B cats have?
No conversion of Nacetylneuraminic acid to Nglycolylneuaminic acid
What are type B alloantibodies
Antibodies in B cats against A antigen; haemolysins and haemagglutins, mostly IgM lesser IgG
What happens if you give Mik pos blood to a Mik neg cat?
Acute haemolytic transfusion reaction
Difference between granulocytic and monocytic Ehrlichia?
Monocytic more likely to develop chronic/subclin after doxycycline - thrombocytopenia and nonreg anaemia
Anaemia in FeLV
Macrocytic non-reg
GCSF in FIV?
Increases viral load.
Coinf with FeLV - more cytopenias
PRCA FeLV in cats?
Subgroup C
Causes of aplastic anaemia in dogs?
Ehrlichia canis, parvo, drug tox, radiation, idiopathic.
Bi/pancytopenia and 95 % marrow is adipose
Myelonecrosis in cats and dogs?
Dog - drugs, immune mediated disease, neoplasia, sepsis
Cats - nonregIMHA, FeLV, myelodysplastic, leukaemia
Good px dogs variable cat
Benign haemophagocytic syndrome?
Bi/pancytopenia and more than 2 % benign haemophagocytic macrophages in bone marrow - exclude myelonecrosis myelofibrosis and marrow inflammation as these can cause the macrophage appearance
Dogs - IMHA SLE sepsis E canis fungal neoplasia myelodysplastic, 20 % idiopathic
Cut off myeloblasts to distinguish myelodysplastic syndrome from leukaemia?
20 %
Px better refractory anaemia or refractory anaemia with excess blasts?
Former - and also less ill
Latter bi/pancytopenia and dysplasia in all cell lines
Types of feline erosive arthritis?
Periosteal proliferative - marked, FeLV/FIV
Minimal new bone - rheumatoid
Features of rheumatoid arthritis?
Subchondral bone lysis, articular cartilage loss, erosion of periarticular bone, joint deformation and ligament destruction
What is rheumatoid factor?
Auto antibody against IgG, has role in opsonising and clearing immune complexes (may be increased in any inflammatory disease), 70 % sensitive - use for monitoring?
Treatment for feline rheumatoid arthritis?
Methotrexate + leflunomide
Criteria for SLE diagnosis?
Three manifestations of autoimmunity, can have two if pos ANA
Pathyophys SLE?
Type II, III and IV hypersensitivity. ABs cf nuclear/cytoplasmic/cell membrane components.
Most common manifestations of SLE? Dogs? Cats
Dog - IMPA, glomerulonephritis and derm, fever
Cat - derm, fever, glomerulonephritis, IMPA. CNS more common than in dogs
Histopath SLE?
Interface dermatitis.
Mononuclear infiltrate at epidermal:dermal junction.
Basal keratinocyte apoptosis/vacuolar change.
Epidermal-dermal separation.
LE cells?
Neutrophil with phagocytosed nuclear material - SLE - spec but not sens
How might ANA be reported?
Titre or pattern of nuclear staining. No pattern with clinical disease severity/nature.
Low ANA in 10 % normal animals.
Anti histone ABs?
Histone coils DNA.
Present up to 70 % SLE.
SLE remission in dogs?
75 % with pred + levamisole.
ANA could corr with clin severity/improvement but might stay low pos.
What might you see in EMH?
More immature haematic cells - leucoerythroblastic effect.
Splenic nodular hyperplasia?
Lymphoid or fibrohistiocytic proliferation, latter intermediate between lymphoid and malignant splenic fibrous histiocytoma. Lymphoid may develop to haematoma in dogs (cats no as diff blood flow pattern)
Arginine and NO?
Need arginine for NO synthesis
Why are Omega 3s anti-inflamm?
Eicosapentanoic acid completes for arachidonic acid (6) for COX/LOX.
Decreased eicosanoid production.
Also PPAR gamma - decrease inflamm cytokines
Name some antipyretics
Steroid, neuropeptide, IL 10. Some pyrogens can be antipyretic at high temps.
Benefits of fever?
Improves survival and shortens length of illness.
Increase immune function ?(mobility/phagocytic ability/proliferation, NK less active though), impairment if > 41.4
Costs of fever?
Increase clin signs, increase metabolic rate, decrease Hb O2 affinity
Immunological effects of calcitriol?
Mostly anti-inflammatory - decreased TLR 4 LPS interaction, decreased TNF production
Poss immunomodulatory? Immune cells have vitamin D receptors
SRMA CSF sampling?
Can increase sensitivity for increased cell count if sample cervical and lumbar
Synovial fluid lymphocyte in IMPA?
Higher in erosive
Pred versus ciclosporin for IMPA?
Same response in small case numbers (70 %)
What is most impacted by cyclosporin - cell or humeral immunity
Cell
Decreased mast cell activity, decreased macrophage activity. Decreased intracellular adhesion molecule. inhibit APC function.
Also inh B cell AB production
Where is ciclosporin primarily excreted?
Bile
Ciclosporin P-glycoprotein interaction?
Ciclosporin substrate for and inhibitor of
Danger of ciclosporin and toxoplasma?
Naive infection during treatment
Breed for idiopathic pyogranulomatous lymphadenitis?
Springer spaniel
Define type I - IV IMPA
I idiopathic
II remote infectious
III GI
IV neoplasia
Vaccination IMPA?
One recent study found no difference
Relapse rate immune mediated neutropenia?
About 1/3rd in a year
What cytokines do cyclosporin and pred impact?
IL 2 and IFN gamma
Difference between SIRS criteria dogs/cats?
Cat include low HR and temp low/high cut off higher
How is folate absorbed?
Folate polygluconate > monogluconate (stomach deconjugation, folate deconjugase)
Folate carrier absorption
B12 absorption?
R protein (haptocorrin) binds after pepsin and acid liberates from animal protein, moves to IF when pH increases and with pancreatic proteases in duodenum. Cubam receptor uptake (receptor mediated endocytosis), transcobalamin II transport to liver
B12 storage in cats?
Rapid depletion 1-2m (rapid enterohepatic turnover). Half life 13 d healthy 5 d GI disease. No transcobalamin I (long term storage)
What are calprotectin, methyl histamine and brominated tyrosine?
S100A2 - calprotectin - neutrophilic inflammation marker - in faec and serum IBD
MH - marks mast cell degran - inc faec and serum IBD
BT - eosinophil activity - inc serum IBD
How does lateral recumbency affect video fluoroscopy?
No pharyngeal impact but decreases oesophageal transit (decreased primary peristaltic waves)
How would you diagnose achlorhydria?
pH > 3 increased gastrin
Also provocative testing eg pentagastrin
Lymphocyte ratio in feline caudal stomatitis?
CD8 >CD4
Breeds for oral eosinophilic granuloma complex?
CKCS, husky, malamute
Sialadenosis - pathophys and management?
Maybe vagus nerve abnormality? Can try phenobarbital - perhaps seizure disorder?
What muscles are affected in masticatory muscle myositis?
Those with 2M - masseter, temporalis, medial and lateral pterygoid. Unique myosin.
What pH is pepsin active at?
1.5 - 3.5
Is GER abnormal?
No, happens frequently in healthy dogs
Hyperregeneratory oesophagopathy histopath?
Spec but not sens for GERD
Long term omeprazole therapy?
Taper if > 2w, rebound hyperacidity
Most common cause of oesophageal stricture?
GER under GA. Muscular layer damaged, fibroblast .
Most common in distal oesophagus.
What decreases oesophageal stricture recurrence?
Triamcinolone intralesional/topical mitomycin C
Where do oesophageal FBs get stuck?
Points of minimal oesophageal distension - thoracic inlet, heart base, hiatus of diaphragm
What XR recumbency for megaoesophagus?
Left lateral best
Congenital megaoesophagus?
Afferent vagal innervation defect? Oesophageal motor supply defect?
Wire-haired fox terrier (auto recessive) and mini schnauzer (partial penetrance).
Various other breeds eg Irish setter, GSD, siamese
How many congenital megaoesophagus cases recover?
20 - 50 %
Most common cause acquired megaoesophagus?
Idiopathic. Vagal/muscle dysfunction? Undx MG? 26 % idiopathic cases have titre - 48 % imp with tx
Idiopathic megaoesophagus breeds?
Large breed middle aged
GSD Irish setter
What would you do if AchAR titre is in grey zone?
Repeat 4-8w esp if acute onset signs
NB in humans often neg in focal MG
What is the likelihood of megaoesophagus in MG responding to therapy?
50 %
Why would hAC cause megaoesophagus?
Impaired muscle carbohydrate metabolism/decreased muscle glycogen stores
How many dogs with dysautonomia have megaoesophagus?
60 %
Possible management options for mega-o?
Bethanecol for striated muscle, cisapride for LES
Negative prognostic factors mega-o?
Aspiration pneumonia
What might be confused for an oesophageal diverticulum in young brachycephalic dogs?
Redundant oesophageal mucosa
Pathophys congenital oesophageal diverticulum?
Herniation of mucosa through muscularis defect
How might an oesophageal diverticulum be acquired?
Pulsion or traction
Congenital oesophageal fistula?
Cairn terrier
What contrast to use if suspect oesophageal/resp comm?
Non-iodinated, iodinated osmolar/chemical pulmonary damage
When guarded px with oesophageal fistula?
Pleural eff, pneumonia, pulm abscess
