Veterinary Medicine - December 2008 - (Page 670)

Immune-mediated hemolytic anemia PEER-REVIEWED count, blood smear, serum chemistry pro le, urinalysis, and urine culture every four to eight weeks as needed to monitor for drug side effects, infections, and disease relapse. A recent study documented that about three months of therapy was suf cient in dogs successfully treated for IMHA, although a subset of dogs needed longer treatment.3 A written drug-tapering and recheck schedule can be provided for the owners to follow, under the supervision of a veterinarian. After nishing all medications, rechecks should occur quarterly for a year, then biannually. Relapse of disease has been documented to be roughly 12% to 24%, although different protocols and studies make comparison dif cult.3,13 If relapse occurs, reinstitute medications at high dosages and taper more slowly. The mortality associated with IMHA is documented to be between 29% and 70%, with a large percentage of deaths occurring within the rst two weeks of diagnosis.3 Predictors of increased mortality in dogs include increased blood urea nitrogen concentrations, decreased platelets, and petechiae at the time of diagnosis. Dogs that survive the rst two weeks after diagnosis have a six-month survival rate of 92.5%.3 These organisms can sometimes be seen on a blood smear, although the best test is a PCR. Treat cats with antibiotics, immunosuppressive therapy, and blood transfusions as needed.1 Similar to dogs, cats with IMHA are initially started on immunosuppressive dosages of glucocorticoids. Little information is available describing the addition of secondary or tertiary immunosuppressive medications in cats with severe IMHA. Possible drugs to add include cyclosporine or cyclophosphamide.41 CONCLUSION When IMHA is rst identi ed, inform owners that the prognosis is variable, treatment is labor-intensive, hospitalization is expensive, and side effects from medications can be severe. Further, since RBC counts and overall stability are often erratic in these patients, prepare owners for the roller-coaster nature of this disease. Owners also need to be prepared for frequent and costly recheck examinations. Although IMHA is a serious condition, patients can have a good prognosis if they respond to treatment, tolerate the side effects of medications needed for treatment, and do not succumb to secondary infections or thromboembolism. The identi cation and treatment of underlying disease, the advent of new immunosuppressive drugs, and good supportive and owner care all contribute to increased survival in patients with IMHA. ACKNOWLEDGMENTS CATS AND IMHA In cats, IMHA is most often secondary to feline leukemia virus (FeLV) or Mycoplasma haemofelis (formerly Haemobartonella felis) infection although it can also be seen with other infections (feline infectious peritonitis, Cytauxzoon felis infection), drug therapy (methimazole, propylthiouracil), toxins (onions), and neoplasia (lymphoma).40,41 One study documented no increased risk of IMHA in hospitalized cats given subcutaneous vs. intravenous famotidine.42 If you suspect IMHA in a cat based on history, clinical signs, and routine diagnostic test results, perform a FeLV test. Patients with FeLV infection often respond well initially to treatment but eventually succumb to the disease. Cats with M. haemofelis infection typically have recurrent episodes of hemolytic anemia. Special thanks to Jennifer Neel, DVM, DACVP, assistant professor of clinical pathology, Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, for providing the photographs in this article. REFERENCES 1. Giger U. Regenerative anemias caused by blood loss or hemolysis. In: Ettinger SJ, Feldman EC. Textbook of veterinary internal medicine. 6th ed. St Louis, Mo: Elsevier Co, 2005;1886-1907. 2. Barker RN. Anemia associated with immune responses. In: Feldman BF, Zinkl JG, Jain NC, eds. Schalm’s veterinary hematology. 5th ed. Philadelphia, Pa: Lippincott, Williams & Wilkins, 2000;169175, 819-826. 3. Piek CJ, Junius G, Dekker A, et al. Idiopathic immunemediated hemolytic anemia: treatment outcome and prognostic factors in 149 dogs. J Vet Intern Med 2008;22(2):366-373. 4. Liang MM, Pfeiffer I, Roth T. The major histocompatibility complex and its role in canine immune-mediated hemolytic anemia and thrombocytopenia, in Proceedings. 16th European Coll Vet Intern Med Companion Anim Congress 2006. 5. Calvert CA, Sammarco C, Pickus C. Positive Coombs’ test results in two dogs treated with amiodarone. J Am Vet Med Assoc 2000;216(12):1933-1936. 6. Van Israel N, French AT, Wotton PR, et al. Hemolysis associated with patent ductus arteriosis coil embolization in a dog. J Vet Intern Med 2001;15(2):153-156. 7. Barker RN, Elson CJ. Red blood cell glycophorins as B and T-cell antigens in canine autoimmune haemolytic anemia. Vet Immunol Immunopathol 1995;47(3-4):225-238. 8. Barker RN, Gruffydd-Jones TJ, Stokes CR, et al. Autoimmune haemolysis in the dog: relationship between anemia and the levels of red blood cell immunoglobulins and complement measured by enzyme-linked antiglobulin test. Vet Immunol Immunopathol 1992:34(1-2):1-20. 9. Schalm OW. Autoimmune hemolytic anemia in the dog. Canine Pract 1975;2:37-45. 10. Stokol T, Blue JT, French TW. Idiopathic pure red cell aplasia and nonregenerative immune-mediated anemia in dogs: 43 cases (1988-1999). J Am Vet Med Assoc 2000;216(9):1429-1436. 11. McManus PM, Craig LE. Correlation between leukocytosis and necropsy ndings in dogs with immune-mediated hemolytic anemia: 34 cases (1994-1999). J Am Vet Med Assoc 2001;218(8):1308-1313. 12. Carr AP, Panciera DL, Kidd L. Prognostic factors for mortality and thromboembolism in canine immune-mediated hemolytic anemia: a retrospective study of 72 dogs. J Vet Intern Med 2002;16(5):504-509. 13. Burgess K, Moore A, Rand W, et al. Treatment of immune-mediated hemolytic anemia in dogs with cyclophosphamide. J Vet Intern Med 2000;14(4):456-462. 14. Weinkle TK, Center SA, Randolph JF, et al. Evaluation of prognostic factors, survival rates, and treatment protocols for immune-mediated hemolytic anemia in dogs: 151 cases (1993-2002). J Am Vet Med Assoc 2005;226(11):1869-1880. 15. Miller E. Immune-mediated hemolytic anemia. In: Kirk’s current veterinary therapy XIV. St. Louis, Mo: Saunders Elsevier, 2009;266-271. 16. Jackson ML, Kruth SA. Immune-mediated hemolytic anemia and thrombocytopenia in the dog: a retrospective study of 55 cases from 1979 through 1983 at the Western College of Veterinary Medicine. Can Vet J 1985;26(8):245-250. 17. Morley P, Mathes M, Guth A, et al. Anti-erythrocyte antibodies and disease associations in anemic and nonanemic dogs. J Vet Intern Med 2008;22(4):886-892. 18. Boozer L, Macintire D. Babesia gibsoni: An emerging pathogen in dogs. Compend Contin Educ Pract Vet 2005;27(1):33-41. 19. Macintire DK, Boudreaux MK, West GD, et al. Babesia gibsoni infection among dogs in the southeastern United States. J Am Vet Med Assoc 2002;220(3):325-329. 20. Stegeman JR, Birkenheuer AJ, Kruger JM, et al. Transfusionassociated Babesia gibsoni infection in a dog. J Am Vet Med Assoc 2003;222(7):959-963. 21. Birkenheuer AJ, Correa MT, Levy MG, et al. Geographic distribution of babesiosis among dogs in the United States and association with dog bites: 150 cases (2000-2003). J Am Vet Med Assoc 2005;227(6):942-947. 22. Neer MN. Ehrlichiosis. In: Greene CE, ed. Infectious diseases of the dog and cat. 2nd ed. Philadelphia, Pa: WB Saunders, 1998;139-147. 23. Strickland KN. Canine and feline caval syndrome. Clin Tech Small Anim Pract 1998;13(2):88-95. 24. McCullough S. Immune-mediated hemolytic anemia: understanding the nemesis. Vet Clin North Am Small Anim Pract 2003;33(6):1295-1315. 25. Scott-Moncrieff JC, Treadwell NG, McCullough SM, et al. Hemostatic abnormalities with primary immune-mediated hemolytic anemia. J Am Anim Hosp Assoc 2001;37(3):220-227. 26. Day MJ. Systemic lupus erythematosus. In: Feldman BF, Zinkl JG, Jain NC, eds. Schalm’s veterinary hematology. 5th ed. Philadelphia, Pa: Lippincott, Williams & Wilkins, 2000;819-826. 27. Scott-Moncrieff JC. Immune-mediated hemolytic anemia: Treatment. In: IMHA: New perspectives on a challenging disease. Thomson Veterinary Healthcare Communications, Lenexa, Kan, 2002:7-11. In: Vet Med 97(10). Sponsored insert. 28. Reimer ME, Troy GC, Warnick LD. Immune-mediated hemolytic anemia: 70 cases (1988-1996). J Am Anim Hosp Assoc 1999;35(5):384-391. 29. Grundy SA, Barton C. In uence of drug treatment on survival of dogs with immune-mediated hemolytic anemia: 88 cases (19891999). J Am Vet Med Assoc 2001;218(4):543-546. 30. Mason N, Duval D, Shofer FS, et al. Cyclophosphamide exerts no bene cial effect over prednisone alone in the initial treatment of acute immune-mediated hemolytic anemia in dogs: a randomized controlled clinical trial. J Vet Intern Med 2003;17(2):206-212. December 2008 VETERINARY MEDICINE

Table of Contents Feed for the Digital Edition of Veterinary Medicine - December 2008

Veterinary Medicine - December 2008 Contents Letters Thanking Our Valued Reviewers Practical Matters Idea Exchange Why Do Dogs and Cats Eat Grass? Managing Atypical and Critical Cases of Primary Hypoadrenocorticism in Dogs Behaviors Suggestive of Postoperative Pain in Cats What to Consider When Considering Digital Radiography Avoid Common Bandaging Mistakes in Dogs and Cats IMHA: Diagnosing and Treating a Complex Disease CE Form/Advertiser Index Marketplace/Classifieds Mind Over Miller

Veterinary Medicine - December 2008

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