Veterinary Medicine - December 2008 - (Page 662)

Immune-mediated hemolytic anemia TABLE 2 PEER-REVIEWED Selected Causes of Canine and Feline IMHA* Causes, Underlying Disorders, and Possible Triggers Primary IMHA Idiopathic (primary IMHA) Breed predispositions in primary IMHA American cocker spaniels, English springer spaniels, Old English sheepdogs, Irish setters, poodles, and dachshunds; no breed association has been found in cats Alloimmune hemolytic anemia Neonatal alloimmune hemolytic anemia Incompatible transfusions Toxic causes of secondary IMHA Bee sting envenomation Notes on Further Investigation and Diagnostic Testing Diagnosed when other causes of hemolysis have been ruled out. Dog leukocyte antigens have been associated with canine primary IMHA in a recent study. Blood type A kittens born to blood type B queens are at risk. Cats have naturally occurring antierythrocyte antibodies. Bee venom contains hyaluronidase, histamines, and hemolysins that cause toxic and hemolytic effects. Treatment consists of supportive care and glucocorticoids. Possible drug-related causes of secondary IMHA** Antimicrobial sulfonamides (sulfamethox- An idiosyncratic toxicosis that occurs in people and dogs; the hydroxylamine and nitroso azole, sulfadiazine, sulfadimethoxine) metabolites are thought to be the culprit in the adverse reactions to these drugs. Cephalosporins In people, second- and third-generation cephalosporins are associated with severe IMHA. In dogs, immune-mediated cytopenias have been documented in patients receiving large doses for extended periods. One study described a positive Coombs test result in two dogs being treated with this antiAmiodarone arrhythmic agent; has also been associated with IMHA and thrombocytopenia in people. Methimazole Cats treated with methimazole for hyperthyroidism can have rare but serious hematologic side effects from the drug. A positive Coombs test result is seen in 1.5% of treated cats; hemolytic anemia is seen in 0.5% of treated cats. Propylthiouracil Propylthiouracil, formerly used to treat hyperthyroidism in cats, has fallen out of favor because of adverse reactions, including IMHA and thrombocytopenia. Infectious conditions and causes (bacterial) of secondary IMHA Pyometra, abscess, urinary tract infecInvestigate for an underlying infection. tions, discospondylitis, endocarditis Ehrlichia canis Demonstrate infection with cytologic examination or IFA or PCR testing. Mycoplasma species Generally causes anemia in cats and in dogs that have undergone splenectomy. Only seen in direct blood smears 50% of the time. Use PCR testing for detection. Leptospira species Examine the patient for other clinical signs associated with leptospirosis. Use a microscopic agglutination test or ELISA for detection. Infectious causes (parasitic) of secondary IMHA Babesia species Can use direct blood smears from peripheral capillary bed or IFA, ELISA, and PCR testing for detection. Diroﬁlaria immitis Investigate whether the patient is receiving a heartworm preventive; perform an ELISA. Leishmania species Investigate other clinical signs, travel history, and breed. Consider ELISA, PCR, and cytologic or histologic examination for diagnosis. Cytauxzoon felis Investigate other clinical signs and tick exposure. Consider blood smear examination. Anaplasma phagocytophilum In one report, a dog presenting with anemia and macroagglutination was shown to be infected with A. phagocytophilum. The patient also presented with pyrexia, pallor, petechiation, and polyarthropathy. Infectious causes (viral) of secondary IMHA Feline leukemia virus Consider an ELISA test Respiratory or gastrointestinal viruses Investigate for an underlying infection. Immune causes of secondary of IMHA Systemic lupus erythematosus Perform an ANA test; false positive and false negative results are common. Neoplastic causes of secondary IMHA Lymphosarcoma, leukemia, multiple Investigate for other physical examination, diagnostic imaging, or blood work abnormalities. myeloma, hemangiosarcoma * Sources: References 1, 4, 5, 24, and 43-48. * * Identi cation of drug reaction, discontinuation of the drug, supportive care, and avoidance of reexposure are all key in managing these cases. 662 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

For optimal viewing of this digital publication, please enable JavaScript and then refresh the page. If you would like to try to load the digital publication without using Flash Player detection, please click here.