49:11

Immune-Mediated Hemolytic Anemia

https://d360v0nslzk1hl.cloudfront.net/thumbnail_images/59/thumbnail_59.png?Expires=1768710996&Signature=FLNwlhARpkHp6haKV8hmbKDcebWSD-zDu-DzBvbiHOgdT0zFvN-rY3XK-IjqlKiaKLfYu4xmnTFHITgcNoUGJDTDb3XmeuJGiAYY9MT2euoAPgtwaY8BHqpg0gEEu41jwIRM3lVIGgfchOWa9grqdwHKiz-yAA7wSiioXhHrepWuhdIT4dEFE6U2fTXLB5TiFnZ0ruccgkJzZMV2RFZaqVeAiNgkFqj~echTkawKk26wHyAs4Ooq~pC0Q6XD2pk53yygGAHuJs8~pgBywP3k~RF36mE94hcaYP8wEwErrjhPyYh4KZByPIAaVCZNN-yr47PhK9vbV2Y3IemD5uHDCg__&Key-Pair-Id=APKAJYRCU5335P523QIQ

Remo Lobetti, BVSc, MMedVet (Med), PhD Dipl ECVIM (Int Med) Remo Lobetti 2019-07-09

Subtitles unavailable

Slides

Related Videos

Show All

p.1

p.1

Immune-Mediated Hemolytic Anemia
Remo Lobetti, BVSc, MMedVet (Med), Ph.D. Dipl ECVIM (Int Med)

p.1
p.2

p.2

Introduction
>Destruction or phagocytosis of RBC
>Primary vs. secondary
>Dog - common and often fatal
>Cat - uncommon

p.2
p.3

p.3

Pathophysiology
>Red cell antibodies
>Primary/idiopathic IMHA:
>Normal erythrocytes
>Secondary IMHA:
>Antigenically altered erythrocytes:
>Exposure of hidden RBC antigens
>Cross reaction with new antigens
>Non-specific antibody reaction

p.3
p.4

p.4

Image

p.4
p.5

p.5

Immunoglobulins
>IgG and/or IgM antibodies
>IgG antibodies:
>Cannot directly agglutinate RBC unless a large
amount of antibody is present
>Phagocytosed occurs in spleen
>IgM antibodies:
>Direct agglutination of RBC
>IgM can detach after complement activation
and bind to other RBC
>Phagocytosed occurs in liver

p.5
p.6

p.6

Complement
>Binding of complement proteins to RBC
>Complement activation:
>Intravascular lysis
>Extravascular lysis
>Spherocytes

p.6
p.7

p.7

Other Factors
>“Membrane attack complex’:
>CI (serine protease)
>Associated with complement cascade
>Damages RBC membrane:
>Influx of water and electrolytes
>Cell swelling
>Lysis
>Phagocytosis by splenic macrophages

p.7
p.8

p.8

Antibody
Complement
RBC membrane antigen
C3bR
FCR
Macrophage
Spherocyte
Phagocytosed membrane fragment

p.8
p.9

p.9

Primary IMHA
>Canine:
>Young to middle-aged
>Female spayed
>Specific breeds
>Feline:
>Young
>Male

p.9
p.10

p.10

Primary IMHA (Cont.)
>No obvious underlying cause
>True idiopathic AIHA
>Can be associated with:
>Evans syndrome
>SLE

p.10
p.11

p.11

Secondary IMHA Aetiology
>Infectious
>Drugs
>Toxins
>Neoplasia

p.11
p.12

p.12

Secondary IMHA Infectious
>FeLV
>Bacterial endocarditis
>Ehrlichiosis
>Leptospirosis
>Hemoplasmas
>Babesiosis
>Chronic bacterial infections
>Systemic fungal infections
>Helminths

p.12
p.13

p.13

Secondary IMHA Drugs
>Penicillin
>Cephalosporin
>NSAIDs
>Potentiated sulphonamides
>Endogenous estrogen
>Vaccines
>Blood transfusions

p.13
p.14

p.14

Secondary IMHA Toxins
>Beestings
>Snake bites

p.14
p.15

p.15

Secondary IMHA Neoplasia
>Lymphoma
>Leukemia
>Hemangiosarcoma

p.15
p.16

p.16

Diagnostic Approach
>History and clinical examination
>Urine and fecal analyses
>Hematology
>Serum biochemistry

p.16
p.17

p.17

History and Clinical Signs
>History:
>Recent vaccinations
>Exposure tick/parasites
>Recent therapy
>Clinical:
>Anemia
>Hemoglobinuria
>Fever
>Splenomegaly

p.17
p.18

p.18

Image

p.18
p.19

p.19

Urine and Fecal Analyses
>Concentrated specific gravity
>Dipstick
>Bilirubinuria
>Hemoglobinuria
>Proteinuria
>Sediment
>RTE cells
>Fecal

p.19
p.20

p.20

Image

p.20
p.21

p.21

Image

p.21
p.22

p.22

Image

p.22
p.23

p.23

Hematological Findings
>Dependent on onset:
>Inappropriate anemia
>Regenerative anemia
>Spherocytosis
>Inflammatory leukogram
>Thrombocytopenia

p.23
p.24

p.24

Image

p.24
p.25

p.25

Image

p.25
p.26

p.26

Image

p.26
p.27

p.27

Haematological Findings (Cont.)
>Positive in-saline-agglutination
>Positive Coombs’ test
>Evidence of DIC:
>Prolonged PT/PTT
>Elevated FDP
>Elevated d-dimers

p.27
p.28

p.28

Image

p.28
p.29

p.29

Image

p.29
p.30

p.30

Antibody-mediated agglutination
Saline added
Gross granularity
Persistent granularity Positive test result
Rouleaux formation
Saline added
Gross granularity
Loss of granularity Negative test result

p.30
p.31

p.31

Image

p.31
p.32

p.32

Fc Receptor
Removal of a piece of RBC membrane
Spherocyte
Normal discoid
RBCs

p.32
p.33

p.33

Biochemistry
> Elevated liver enzymes (ALP/ALT)
> Bilirubinemia
> Elevated urea with normal creatinine
> Elevated proteins

p.33
p.34

p.34

Diagnostic Approach (Cont.)
>Radiographs
>Abdominal ultrasonography
>Echocardiography
>Urine and blood culture
>Serology and/or PCR
>Bone marrow aspirate/biopsy

p.34
p.35

p.35

Diagnostic imaging
> Thoracic radiographs
> Spinal radiographs
> Ultrasonography
> Echocardiography

p.35
p.36

p.36

Image

p.36
p.37

p.37

Image

p.37
p.38

p.38

Image

p.38
p.39

p.39

Image

p.39
p.40

p.40

Image

p.40
p.41

p.41

Image

p.41
p.42

p.42

Summary
>Exclude secondary IMHA before diagnosing primary IMHA
>Early ’80’s – 90% primary IMHA
>Now – 60% primary IMHA

p.42
p.43

p.43

Therapy
>Treat primary cause
>Immunosuppressive therapy:
>Short course with secondary IMHA
>Prolonged course with primary IMHA
>Supportive therapy

p.43
p.44

p.44

Corticosteroids
>Decrease Ab production
>Decrease Fc-mediated destruction of red cell
>Prednisone - 2mg/kg bid

p.44
p.45

p.45

Cyclophosphamide
>Block DNA and RNA synthesis
>Suppress Ab production
>Suppress lymphocytes
>2mg/kg oid 4 days per week

p.45
p.46

p.46

Cyclosporine
>T-cell suppression
>Inhibition of immune response by decreased production of IL-2
>5mg/kg bid

p.46
p.47

p.47

Azathioprine
>Suppress T-cell function
>2 mg/kg oid

p.47
p.48

p.48

Danazol
>Reduces red cell fragility
>Block Fc-receptors
>5-10 mg/kg bid

p.48
p.49

p.49

Intra-venous Immunoglobulins
>Block/saturate Fc-receptors
>0.5-1.5 g/kg IV over 6 hours

p.49
p.50

p.50

Other Drugs
>Mycophenolate
>Leflunomide

p.50
p.51

p.51

Therapeutic Approach
>Prednisone
>Prednisone & azathioprine or cyclophosphamide
>Prednisone & cyclosporine
>Response based on rising Ht

p.51
p.52

p.52

Treating Tissue Hypoxia
>Blood transfusion:
>Ht
>Acuteness of onset
>Clinical signs of hypoxia
>Products:
>Whole blood
>Packed RBC
>Oxyglobin®
>Blood typing

p.52
p.53

p.53

Image

p.53
p.54

p.54

Thromboembolism
>Common cause of mortality
>Poor prognosis if occurs
>Causes:
>Increased procoagulant factors
>Decreased anticoagulant factors
>Vasculitis >Enhanced platelet reactivity

p.54
p.55

p.55

Thromboembolism (Cont.)
>Contributing factors:
>Icterus
>Catheters
>Therapy:
>Heparin 150-200 units/kg tid-qid
>Aspirin 0.5 mg/kg bid
>Clopidogrel?
>Plasma with concurrent DIC

p.55
p.56

p.56

Supportive Therapy
>Fluids
>Gastric protectants ??
>Specific organ therapy

p.56
p.57

p.57

SonoPath.com
VETERINARY SONOGRAPHIC DIAGNOSTICS

p.57

Please log in to watch this content

Haven't created an account yet?