IMHA and Immune Mediated Diseases (E2) Flashcards
What type of HS rxn is IMHA and against what does the reaction occur?
Type II (2)
Glycophorin on Erythrocytes
What are the clinical signs accompanying IMHA due to tissue hypoxia?
Tachypnea
Tachycardia
Grade II-III systolic hemic murmur
S3 gallop
Increased CO
Vomiting, diarrhea
What antibody mainly causes extracascular hemolysis in IMHA? Which causes intravascular hemolysis? Which one activates the compliment system?
IgG
IgM- activates compliment system
What drugs can cause secondary IMHA?
Penicillins
Cephalosporins
Sulfas
Methimazole
Levamisole
Dipyrone
Chlorpromazine
How does Feline neonatal isoerythrolysis occur?
When a type A or AB kitten consumes colostrum from a type B cat
What should you include in your clinical exam to ensure no secondary cause of IMHA is present?
3 view thoracic rads
Abdominal US
Heartworm antigen test
PCR (e.g.4Dx)
Fecal exam for hookworm
If you have a low hematocrit but a normal [Hb] what does this indicate?
Hemoglobinemia
What does a Coobs test look for?
Auto-antibodies against RBCs
What does an Osmotic Fragility Test confirm?
Hemolysis
What would warrent administration of packed RBCs for a dog with IMHA?
Elevated respiratiojn rate, dyspnea
Elevated cardiac rate
How do you calculate the amount of blood a patient needs to get via transfusion?
BW (kg) x K x [(25-recipient PCV)/ PCV of doner blood]
K in dogs = 90
K in cats= 66
A 18kg dog is diagnosed with primary IMHA. The current PCV is 12% and the donor blood PCV is 70%. How much blood is required (mL) ?
- 8mL
* BW=18kg*
* K=90*
* PCV(recipient)= 12*
* PCV(doner)=70*
18kg x 90 x [(25-12)/70]
What is the best treatment for idiopathic IMHA? What second line therapies can be given for immunosuprresion in combination with prednisone?
Prednisolone (2mg/kg BID) +Azathioprine (2mg/kg SID then EOD)
Second line: Cyclosporin SID or Mycophenolate mofetil BID
What can be given to a dog with IMHA to prevent a coagulopathy?
Aspirin (low dose)
Clopidogrel
Individually adjusted unfractionated heparin
Hypoalbuminemia is a negative prognostic indicator for a dog with IMHA, what does this indicate?
Severe hepatopathy
What is the hallmark of immune-mediated thrombocytopenia (ITP)?
Surface bleeding: petechiae, ecchymosis, epistaxis
What is the typical platelet count in a dog with ITP?
<150,000/ mcL
(N= 200,000-500,000)
Where is the most common place for petechial hemorrhage? What does prolonged surface bleeding eventually lead to?
Gums
Pinna
Anemia
Which ITP disease rarely causes petechiae, but does cause bleeding post-op or from trauma?
Von Willebrands Disease
You are spaying a young, healthy dog and note inappropriately long clotting times and intra-op bleeding when there should not be any. You check the PTL count, which was normal. What other test should you perform, which would if negative strongly indicate that the dog has Von Willebrands Disease?
PT/aPTT
What factors are decreased in a dog with vWB disease? Depletion of which factor causes the most severe bleeding?
Type 1, 2, or 3 vWB factors
Type 3 is most severe (no circulating vWBF)
A BMBT time over _____ is abnormal. List a few breeds predisposed to vWB disease.
4 minutes
Doberman, Bernese Mnt Dog (get type 1, sometimes 2 dz)
Dutch Kooiker (gets type 3 dz)
Goldendoodle (get type 2 dz)
What 2 diagnostics exist for vWB disease?
ELISA plasma vWB
DNA testing
What therapies exist for vWB Disease?
Desmopressin (ADH, Vasopressin…)
Blood components: FWB, FFP, Cryp
What do antibodies target in pripary ITP? How does secondary ITP occur? Which is more common?
Fibrinogen receptor (GpIIb/IIa)
Antigenic stimulation (drug, disease, neoplasia) leading to Ab formaiton
Secondary is most common, specifically due to neoplasia
Name one inflammatory diseaase and one toxin that can cause ITP.
Pancreatitis (SIRS)
Africna bee envenomation
What must you do in addition to a CBC when diagnosing ITP?
Blood smear (count PTLs)
What is the downside of the PTL-bound antibodiy test from Kansas university?
Does not differentiate between primary and secondary ITP
How many PTL should you see per high power field? What does it indicate if you count <2 PTL per field?
6-8+
<2PTL/ hpf = <50000 total PTLs
In addition to removing the offendng cause, what can be given to treat secondary ITP (i.e. what is the best line therapy)? How long does it take to take effect?
Glucocorticoids (immunosuppressive) + Vincristine (anti-mitotic)
7 days
What is the basic MOA of human IgG therapy (IV)? Is it better than vincristine for increasing PTLs?
Blocks the macrophages from phagocytising PTLs
Not better, and much more expensive
What can you use to treat ITP if glucocorticoids are counterindicated?
Mycophenolate mofetil
(Chlorambucil for cats)
What is the best source of PTLs in practice? How long does a PTL live in circulation?
FWB
(Ideally DEA 1.1. neg for dogs if not typed)
Last 8-12 days
What can be seen in a radiograph of joints affected by immune-mediated polyarthritis?
Loss of joint space (Loss of cartilage)
Sclerosis
Osteophyte formation
+/- Periosteal reaction
What does neutrophilic inflammaiton of a single joint most commonly indicate?
Bacterial infection
What are the 3 general causes of IMP?
Infectious
Reactive
Primary idiopathic immune-mediated
What are the forms of prmary IMP? What are some causes and breed predispositions of each?
Non-erosive: SLE, Shar-pei Fever, Akitas
Erosive: Greyhounds, idiopathic rheumatoid arthritis, Cats- periosteal proliferative polyartritis
Overexpression of what causes Familial Shar-Pei Fever? How is it treated?
Hyluronic acid
NSAID, corticosteroids (for cutaneous mucinosis), colchicine (amyloidosis of kidney and liver)
What are the typical findings when diagnosing systemic lupus erythematpsos (SLE)?
At least 2 separate manifestations of autoimmunity
+
Presence of antinuclear antibodies
What are the 4 general causes for SLE?
Genetics
Environmental factors (IV light, estrogen, prolactin…)
Drugs
Infectious agents
What is the most common complaint in dogs with SLE? What other CS commonly occur? How many of clinical signs need to be present for a diagnosis of SLE?
Lameness (due to polyarthropathy)
Fever, Renal disorders, dermatologic lesions
At least 2 needed
What diagostics can you perform to help you diagnose SLE?
ANA
Lupus erythematosus Cell Test
What does proteinuria in a dog with SLE indicate?
Glomerulonephritis and a poor prognosis
