Red Cell Disorders Flashcards
What are the clinical signs/exam findings of patients with anemia?
- Clinical Signs: (severity reflects speed of disease)
- Weakness, exercise intolerance
- Poor appetite
- Lethargy
- Physical Exam:
- Pale mucous membranes
- Tachycardia
- Icterus with hemolysis
- Finding specific to etiology
How is Anemia classified as Non-regenerative or Regenerative?
- Red blood cell indices
- Reticulocyte count
What findings are common in Regenerative/Pre-regenerative anemia?
- RBC:
- spherocytes, Heinz bodies, ghost cells, MCV/MCHC
- Presence of icterus, hemoglobinuria
- PE: mass, fleas, melena
What causes Regenerative/Pre-regenerative anemia?
- Hemolysis
- Blood Loss
How is the cause of Non-regenerative anemia determined?
Bone marrow aspirate and core biopsy
How is a Reticulocyte count completed
- Absolute Reticulocyte count: (RBC count x (Reticulocyte %/100))
- Dogs >100,000 (regen)
- Cats: Aggregates >60,000 (regen)
Common causes of hemorrhage leading to Regenerative Anemia?
- Trauma
- Coagulopathy
- Neoplasia (HSA, GI tumor)
- Parasites (fleas, hookworms)
What is the most common cause of iron-deficiency anemia?
Bleeding GI tumor
Common causes of hemolysis resulting in regenerative anemia?
- Immune-mediated
- Parasitic/Infectious
- Toxin/Oxidative injury
- Enzyme Deficiency
- Hypophosphatemia
- Microangiopathic Disease
What is Immune-mediated Hemolytic anemia?
- Primary: loss of self tolerance
- Autoantibodies to cell surface antigens
- No inciting cause identified = idiopathic
- Secondary: dysregulation of immunity
- Infection, inflammation, neoplasia, drug therapy
- Cross reacting antigen, RBC membrane damage exposes antigen or antigens attached to RBC membrane
- Idiopathic
- Look for Underlying cause
How is IMHA diagnosed?
- Regenerative anemia
- 15-30% initially non-regen
- Spherocytosis
- 75-90% of cases
- Autoagglutination
- 60-80% of cases
- Direct antibody tests
- Coomb’s test (40-80% positive)
- RBC surface antibodies (67-100% positive)
When is IMHA non-regenerative?
- Peracute IMHA
- 3-4 days to mount a response
- “re-regenerative”
- Non-regenerative IMHA
- Erythroid hyperplasia
- Erythroid maturation arrest
- Precursor-directed Immune-mediated Anemia (PMIA)
- Pure red cell Aplasia
What is the mortality of IMHA?
- 25-70% reported mortality
- <10% If live past first 2 weeks
- Pulmonary thromboembolism
- Hypoxia-related
- Multi-organ dysfunction
- Infectious complications
How is IMHA treated?
- Prednisone (Prednisolone, Dexamethasone)
- 2mg/kg/day or 60mg/M2/day
- First line therapy
- Inhibits uptake of antibody-coated RBCs
- Only treatment most dogs will need
- response in 3-5 days
- Does not affect anibody production
- insufficient for intravascular iMHA
- Insufficient for autoagglutination
- Cyclosporine
- first drug added
- minimal toxicity
- Azathioprine
- Myelosuppressive
- least expensive, slower onset
- Leflunomide
- Mycophenolate mofetil
What are the adjunct therapies for IMHA (with autoagglutination)?
- Heprin therapy
- in hospital
- Clopidogrel (Plavix) or Aspirin therapy
- ULDA is questionably effective
- Rivaroxaban (Xarelto)
- 0.9mg/kg/day
- Factor Xa inhibitor
What parasites cause hemolysis?
- Babesia gibsoni (pitbull)
- Babesia canis (greyhound)
- Mycoplasma hemofelis
- Mycoplasma hemocanis
- uncommon
What are some other common causes of hemolysis?
- Zinc
- skin outments
- pennies (>1893)
- metalic items
- Others
- Onions/garlic
- Acetaminophen
- Benzocaine spray
- Skunk
What is Phosphofructokinase (PFK) deficiency?
- Exacerbated by pantin, barking, etc
- Intermittent hemoglobinuria
- DNA testing available
- most commonly affects English springer spaniels
What is Pyuvate Kinase (PK) deficiency
- Myelofibrosis and osteosclerosis
- Hemosiderosis with hepatic failure at <5 yo
- Common in Basenjis, beagles, others
What is Hypophosphatemia?
- P < 2.5 mg/dL
- Deplete ATP ⇢ ⇡osmotic fragility and oxidative injury
- Etiology: Diabetic ketoacidosis, refeeding syndrome
What is Microangiopathy?
- Cell fragmentation - schistocytes
- Etiology:
- Heartworm disease, hemagiosarcoma, DIC
What is a Histiosarcoma?
- Variable presentations
- Hemolytic anemia, Thrombocytopenia
- Poor response to chemotherapy
What causes hemolytic anemias in cats?
- Drug reactions
- FeLV, FIV, FIP
- Mycoplasma hemofelis
- Cytauxzoonosis
- Primary IMHA
What are the common causes of Non-regenerative Anemia?
- Decreased Production:
- Systemic disease
- Anemia of chronic disease
- Chronic kidney disease ⇣EPO
- Hypothyroidism
- Bone Marrow disease
- Neoplasia
- Myelofibrosis/myelodysplasia/pure red cell aplasia/aplastic
- Immune mediated
- Systemic disease
What are the causes of Myelofibrosis in Dogs?
- Primary (idiopathic)
- Rare
- Atypical precursors, bone marrow fibrosis
- Secondary
- Toxic insult, IMHA, neoplasia, drug tx,
- Short survival time with malignancy
How is Myelofibrosis treated?
- Immunosuppressive therapy (~60% success)
- Erythropoietin therapy (variable success
Common causes of non-regenerative anemia in cats?
- Chonic renal failure
- FeLV, FIV infections
- immune - Pure Red Cell Aplasia
- Myelodysplastic syndromes
- Dugs
- Idiopathic
