ACVIM consensus statement on the diagnosis of immune‐mediated hemolytic anemia in dogs and cats

Abstract

Immune‐mediated hemolytic anemia (IMHA) is an important cause of morbidity and mortality in dogs. IMHA also occurs in cats, although less commonly. IMHA is considered secondary when it can be attributed to an underlying disease, and as primary (idiopathic) if no cause is found. Eliminating diseases that cause IMHA may attenuate or stop immune‐mediated erythrocyte destruction, and adverse consequences of long‐term immunosuppressive treatment can be avoided. Infections, cancer, drugs, vaccines, and inflammatory processes may be underlying causes of IMHA. Evidence for these comorbidities has not been systematically evaluated, rendering evidence‐based decisions difficult. We identified and extracted data from studies published in the veterinary literature and developed a novel tool for evaluation of evidence quality, using it to assess study design, diagnostic criteria for IMHA, comorbidities, and causality. Succinct evidence summary statements were written, along with screening recommendations. Statements were refined by conducting 3 iterations of Delphi review with panel and task force members. Commentary was solicited from several professional bodies to maximize clinical applicability before the recommendations were submitted. The resulting document is intended to provide clinical guidelines for diagnosis of, and underlying disease screening for, IMHA in dogs and cats. These should be implemented with consideration of animal, owner, and geographical factors.

ACVIM consensus statement on the treatment of immune‐mediated hemolytic anemia in dogs

“…Therefore, diagnostic evaluation should be expedited in cases in which underlying cancer or infectious diseases are suspected. Further guidance is available in the Consensus Statement on Diagnosis of Immune‐Mediated Hemolytic Anemia in Dogs and Cats …”

“…Our recommended approach is summarized in Figure . Failure to respond to treatment as expected should prompt consideration of whether criteria for diagnosis of nonassociative (primary) IMHA have been fulfilled, as outlined in the Consensus Statement on Diagnosis of Immune‐Mediated Hemolytic Anemia in Dogs and Cats …”

“…29. We recommend confirming the relapse using standard criteria for the diagnosis of IMHA (see Consensus Statement on Diagnosis of Immune‐Mediated Hemolytic Anemia in Dogs and Cats) to ensure that there is no alternative cause of anemia.…”

“…Splenectomy per se is a procedure associated with a low risk of short‐term complications, but we recommend that immunosuppressive and antithrombotic medications be stopped or their dosage decreased to a minimum before surgery is undertaken. Further recommendations regarding screening for vector‐borne agents are provided in the accompanying Consensus Statement on Diagnosis of Immune‐Mediated Hemolytic Anemia in Dogs and Cats …”

Effects of clopidogrel and prednisone on platelet function in healthy dogs

“…Mortality rates in dogs with primary immune‐mediated hemolytic anemia (IMHA) historically have been high (50%‐70%), 1,2 primarily as a consequence of fatal thromboembolism 1‐3 . Standard treatment for dogs with IMHA includes immunosuppression, thromboprophylaxis, and supportive care 1,4,5 . Glucocorticoids are the most commonly used immunosuppressive agent for the treatment of IMHA in dogs 5 .…”