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Haemolytic AnaemiaSara M. Cowan, BS, DVM (hons)
Dipomate ACVIM
13 April 2011
Introduction Anaemia is common
Loss, lysis, decreased production
Immune mediated haemolytic anaemia
OBJECTIVES• Tidbits on IMHA• Review other causes of haemolysis
Subjective + Objective Clues
Usually nonspecific and variable
Sometimes• Pigmenturia• Icterus• Historical clues
Objective Clues PCV/TP
Urinalysis
Serum bilirubin
Reticulocyte
Blood smear
Agglutination
Images courtesy http://www.vet.uga.edu
Courtesy John Harvery, University of Florida
Diagnosis Classify the anaemia as haemolytic
• Regenerative or Pre-regenerative Rarely non-regenerative
• Evidence of RBC breakdown products or damage Bilirubin Hemoglobin RBC and precursor morphology
Reticulocytes, NRBC, anisocytosis, polychromasia Spherocytes, agglutination Heinz bodies Schistocytes
Haemolytic Anaemia Defined
Increased erythrocyte destruction• Intravascular• Extravascular
Causes of Haemolysis IMHA
• Primary• Secondary
Fragmentation
Inherited
Toxic
Miscellaneous
IMHA Infection
• Cats: Haemotropic Mycoplasma spp., retroviral, FIP, Cytauxzoon felis, Babesia felis
• Dogs: Leptospira, Dirofilaria, (Bartonella), Ehrlichia, Babesia,
Anaplasma, Haemobartonella canis, Histoplasma Neoplasia
• Lymphoma, HSA, Leukaemias, carcinoma, sarcoma Drugs
• TMS, Penicillins, Cephalosporins, Levamisole, Phenylbutazone, Dipyrone, Chlorpromazine, Griseofulvin (C), vaccination?
IMHA
vet.cornell.edu/clinpath
Rickettsia felis Rickettsia felis as Emergent Global
Threat for Humans Emerg Infect Dis 2008, Carlos E. Pérez-Osorio
Deadly cat-flea disease hits Australia SMH, Julia Medew, Jan 6, 2011
Australian prevalence studyPrevalence of Bartonella species, Rickettsia felis, haemoplasmas and the Ehrlichia group in the blood of cats and fleas in eastern Australia. Aust Vet J. May 2010;88(5):160-5. V R Barrs et al
R. felis DNA was amplified from 22 flea sets (19.8%), but not from cats.
Fragmentation Hemangiosarcoma
• Only 3 of 24 dogs had microangiopathic hemolysis Hemostatic Abnormalities in Dogs With Hemangiosarcoma JVIM 2008
DIC
Fragmentation Dirofilariasis (D)
• Kills more dogs than IMHA
Vasculitis
Haemolytic Uraemic Syndrome
Splenic torsion (D)
Near drowning, heat stroke, burns
InheritedMembrane DefectsErythroenzymopathiesErythrocyte Production Defects(No hemoglobinopathies)
When to suspect• *Young age• *MILD haemolysis• *SEVERE anaemia but well compensated patient• *Intermittent anaemia• *Exercise-induced crises• *Massive splenomegaly• *Massive reticulocytosis
InheritedMembrane Defects Elliptocytosis Mixed breed dog* (mild microcytic anemia) Stomatocytosis Alaska malamute (mild anemia with chondrodysplasia) Miniature and Middle Schnauzers (no chondrodysplasia) Spherocytosis Golden Retriever (mild anemia, gastrointestinal signs) Osmotic fragility English Springer Spaniel (mild anemia) Abyssinian, Somali and DSH cats (intermittent anemia)
InheritedErythroenzymopathies PFK deficiency
ESS*, Cocker Spaniel*, mixed breed dogs* (induced hemolytic crises, myopathy) PK Deficiency
Basenji*, Beagle*, Poodle, WHWT*, Cairn Terrier*, Chihuahua, Dachshund, Abyssinian*, Somali* cats, DSH* cats (intermittent anemia)
Porphyria - DSH and Siamese cats (only some with anemia) Methemoglobin reductase Deficiency (cytochrome b5 reductase deficiency)(erythrocytosis)
Many canine breeds, DSH cats
Inherited 3yo FS Springer Spaniel Agility training classes Centennial
Park Trainer noted red, then brown urine Often trembles after rigorous
exercise
Inherited – PFK deficiency English Springer Spaniel Cocker Spaniel_____________________________________ Chronic haemolysis
• Persistent bilirubinuria, reticulocytosis
Exercise induced crises• Pigmenturia, myopathy
Can have normal life span
Inherited – PK deficiency Various smaller breeds and cats
Presentation• < 5 years• Pale mm but well compensated
Massive reticulocytosis Death usually by 5 years
• Anaemia• Hemosiderosis, liver failure• Myelofibrosis, osteosclerosis (D)
Inherited 3yo FS Abyssinian Immigrated from UK last year Outdoors, returns unwell PE: Pale, splenomegaly, no murmur PCV 14%/TP 68 g/L serum icteric FeLV/FIV negative Bile acid tolerance test ok Recurred after doxycycline trial
Toxic Oxidant Injury
• MetHb• Heinz Body Anaemia• Hemolysis
History is important• Garlic, onions• Naphthalene, benzocaine• Paracetamol (C)
Consider heavy metals• Zinc, copper
Heinz Bodies Dogs
• Drugs, onions• Splenectomy
Cats• Diabetes• Lymphoma• Hyperthyroidism• Can be normal
Envenomation Snakes, Bees, Wasps
Dx is problematic• Ambiguous history • Poor quality data
In vitro, case reports, extrapolation • Each snake bite varies
Suspect envenomation?• CK, AST• Coagulation profile• Renal profile
Miscellaneous Hypophosphataemia ?
Neonatal Isoerythrolysis• Type B Queen to Type A or AB kitten
Transfusion reactions to DEA 1.1• 2nd transfusion about 4 days later• 1st transfusion about 2 weeks later
Tips Cats
Focus on the blood smear
Coombs Test
Massive reticulocytosis, mild haemolysis
Poor response to immunosuppression