Answers and Discussion

Answers and Discussions to the Questions:

• What are the typical signalments and clinical signs for IMHA?
  
  IMHA most commonly occurs in young to middle-aged dogs such as Cocker Spaniels, Poodles, Irish Setters and Old English Sheepdogs.  Clinical signs include lethargy, depression and anorexia.  The owner may notice pale mucous membranes.

• How do you diagnose IMHA?
  
  Most cases of IMHA show a regenerative, macrocytic, hypochromic anemia but a nonregenerative anemia may be present if the disease has occurred acutely.   Neutrophilia with a left shift and monocytosis may occur.  Autoagglutination is diagnostic for IMHA but this must be distinguished from rouleaux formation.   Rouleaux will disperse with saline (add a drop to a drop of blood on a slide).   You may also see elevated liver enzymes or bilirubin and hyperproteinemia.   Urinalysis may show bilirubinuria or hemoglobinuria.  A positive Coombs' test is consistent with IMHA--false-positive results are not common but false-negatives may occur because of inadequate antibody or complement on RBC's or previous steroid treatment.
  
• How do you treat IMHA?
  
  Prednisone is the drug of choice, given at 1-2 mg/kg PO BID.  This dose is continued until the PCV begins to rise, usually about 2-4 weeks.  If PCV improves, decrease dosing to SID for another 1-2 weeks.  Then reduce dosage by half and continue for another 1-2 weeks.  After that, taper accordingly.  If prednisone is not working, you can try azathioprine (2 mg/kg PO SID, reduce to 1 mg/kg PO SID after 7-10 days).  This drug is tapered slowly over 2-3 months in recovering animals.   Cyclosporine may also be used but is very expensive (10 mg/kg/day PO or IM for 5 days, then skip two days).  Splenectomy may need to be considered in some cases that have not responded to therapy.  Give heparin or plasma if DIC occurs.   Transfusions may be necessary--whole blood or packed RBC's are best.

• For long-term treatments, what parameters should be monitored on the patient?
  
  Monitor PCV at least once a week while slowly decreasing the steroid dosage.  When using cytotoxic drugs, monitor CBC's for white blood cell and platelet counts which may become low.

• Follow-Up: "Junior" continued to decline despite therapy.  His vomiting and diarrhea worsened and his PCV continued to drop.  He arrested and could not be resuscitated.

Immune-Mediated Hemolytic Anemia Pearls

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Copyright 2000, Wayne E. Wingfield, Colorado State University   
This page was last edited:  04/24/00