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