Hematology Journal Club--The 5 Best Papers 2006
World Small Animal Veterinary Association World Congress Proceedings, 2007
Ann E. Hohenhaus, DVM, DACVIM (Oncology and Internal Medicine)
The Animal Medical Center
New York, NY, USA

1. Willi B, Boretti FS, Baumgartner, et al. Prevalence, risk factor analysis and follow-up of infections caused by three feline hemoplasma species in cats in Switzerland. J Clin Microbiol 2006;44:91-96.

Prevalence of DNA of Mycoplasma haemofelis, "Candidatus Mycoplasma haemominutum", Anaplasma phagocytophilum and species of Bartonella, Neorickettsia, and Ehrlichia in cats used as blood donors in the United States.

The first study documents the prevalence of infection with 3 different hemoplasma organisms in a population of 713 Swiss cats. Using real time PCR, this is the first study to investigate infection with 'Candidatus Mycoplasma turicensis' and found the organism in 1% of the cats studied. The prevalence of 'Candidatus Mycoplasma haemominutum' and Mycoplasma haemofelis was higher in this population of cats, 7% and 2% respectively. Co-infection with 'Candidatus Mycoplasma turicensis' and 'Candidatus Mycoplasma haemominutum' occurred in 50% of cats in this study.

Infection was associated with male gender, outdoor access and increasing age. Infection was not associated with anemia or retroviral infections. Cats were divided into 2 groups, sick and ill, but there was no difference in the prevalence of hemoplasma infections between the 2 groups. One case of 'Candidatus Mycoplasma haemominutum' transmitted via blood transfusion was documented during the study.

The second study in this pair surveyed the prevalence of infection with multiple blood borne infectious agents in 146 blood donor cats from 8 veterinary hospitals in the United States. Included in the survey were 2 hemoplasma organisms, Mycoplasma haemofelis and "Candidatus Mycoplasma haemominutim'. Infections of both types were documented in blood donors. This information coupled with evidence of transfusion transmitted hemoplasmosis in the previous paper, highlight the importance of screening blood donors for infectious diseases in an attempt to prevent transfusion transmitted infection. Prevention of hemoplasma infections in blood donors requires control of the blood sucking arthropod vectors. Community source blood donors, cats with outdoor access and cats with flea exposure were more likely to harbor infectious agents.

2. Frequencies of blood type A, B and AB in non-pedigree domestic cats in Turkey. J Sm Anim Prac 2006:47:10-13.

Determining the blood type of a cat prior to administration of a blood transfusion is critical in providing a safe and effective transfusion. Many studies have shown both breed and geographic variation in the distribution of blood types in feline populations. The purebred cats of Turkey, the Turkish Van the Turkish Angora, have a high prevalence of type B blood in their populations, 60% and 46% respectively. Investigators in Turkey surveyed blood types of 301 non-pedigreed cats in 4 distinct regions of the country and report the results in this study. The results indicated 73% of non-pedigreed cats had type A blood, 25% had type B blood and 2% had type AB blood. No association between haircoat length or gender and blood type were identified. Cats in the isolated eastern Girasun region had the lowest frequency of type B cats, 6%. This information confirms the importance of blood typing every cat prior to administering a blood transfusion.

3. Investigation of physiologic leukopenia in Belgian Tervuren dogs. Gommreen K, Duchateau L, Paepe D, et al. J Vet Intern Med 2006;20:1340-1343.

In certain breeds of dogs, specific hematological values differ from reported reference ranges. These include high hematocrit and hemoglobin in the greyhound and dachshund, lower platelet count in the cavalier King Charles spaniel and microcytosis in the Akita and Shiba inu dogs. Recently, while blood cell counts below the reference range have been reported in Belgian Tervurens in the United States. As many as 65% of these dogs, over 4 years of age were determined to have leukopenia. The Belgian Tervuren originated in Belgium as a herding dog. This study was undertaken in Belgium to determine if physiologic leukopenia reported in this breed in the United States exists in Tervurens in Belgium. Ninety-four clinically healthy Belgian Tervurens and 48 control dogs were studied. Complete blood counts were determined using an automated cell counter. Investigators concluded that only 1 of the 94 Tervurens had a physiologic leucopenia and that this condition is infrequently present in Tervurens in Belgium. The difference between the American and Belgian Tervurens was not determined, but could be due to genetic or environmental differences.

4. Primary immune-mediated hemolytic anemia in 19 cats: diagnosis, therapy and outcome (1998-2004). Kohn B, Weingart C, Eckmann V, et al. J Vet Intern Med 2006;20:159-166.

Primary immune-mediated hemolytic anemia (pIMHA) is a diagnosis of exclusion. It is diagnosed when the Coombs test is positive or persistent agglutination occurs and an underlying disease process cannot be identified. Primary IMHA is common in dogs, but infrequently reported in cats. This German study evaluated the utility of the Coombs test as a diagnostic tool in pIMHA and also reports the treatment and outcome of 19 cats diagnosed with pIMHA.

The Coombs test was performed on 92 cats. It was negative in cats with a wide variety of diseases including; healthy cats, sick cats without anemia and 55 cats with anemia due to a variety of causes. It was positive in 18 cats, 3 with underlying disease. Persistent agglutination was identified in 5 cats, 1 with underlying disease. The remaining 19 cats with diagnosed with pIMHA and entered into the study.

The cats diagnosed with pIMHA ranged in age from 0.5-9 years and were predominantly domestic cats. Slightly more males were diagnosed with pIMHA than females. Anemia was severe in these cats with a mean hematocrit of 12% and in slightly more than half of the cases, there were no signs of regeneration at the time of initial evaluation. Only 1 cat had a concurrent thrombocytopenia and was diagnosed with "Evan's syndrome". Lymphocytosis and hyperglobulinemia was common in these cats as it is in cats with pyruvate kinase deficiency and increased osmotic fragility. Like dogs with pIMHA, cats demonstrated hyperbilirubinemia and elevated liver enzymes. Two cats were lost to follow up. Of the remaining 17 cats treated with prednisone, 15 responded favorably in 8-42 days. Mortality was 24% which appears to be lower than in the dog. Five of 16 cats with follow up greater than 30 days relapsed.

The authors conclude the Coombs test is useful in the diagnosis of pIMHA in the cat, but is not diagnostic for the disorder. A comprehensive diagnostic evaluation including blood work, diagnostic imaging, infectious disease testing and biopsies is required to exclude underlying causes of IMHA in the cat.

5. Disseminated intravascular coagulation in cats. Estrin MA, Wehausen CE, Jessen CR et al. J Vet Intern Med 2006;20:1334-1339.

Disseminated intravascular coagulation (DIC) is a multisystem disorder which occurs secondary to a primary disorder such as neoplasia, sepsis or trauma. This is the first study to specifically evaluate cats with DIC. Previously, DIC has been reported as one type of coagulation disorders in studies of cats with a variety of coagulation abnormalities.

This is a retrospective study performed between 1990-2004. Cats with DIC were identified from the laboratory database. Cats were included only if they had a necropsy performed and an underlying disease associated with DIC could be identified. Evidence of intravascular fibrin deposition or thrombosis in >1 organ had to be identified on necropsy or 3 or more abnormal coagulation tests had to be present for study entry.

Based on the entry criteria, 46 cats were studied. Mean age was 9 years (range7 weeks to 17 years). An equal sex distribution was present. Presenting complaints were nonspecific and included: depression, lethargy, anorexia, weakness and vomiting. The most common underlying disorder was lymphoma, followed by other cancers, pancreatitis and sepsis. Twenty-four percent of cats had multiple underlying disorders. Anemia was common and found in 51% of cats.

Thirty-two of the cats had 3 or more abnormal coagulation tests. The aPTT was prolonged in 100% of cats and the PT in 77% of cats. An elevated PT was strongly associated with non-survival. Only 50% of cats demonstrated thrombocytopenia. Red blood cell fragmentation was identified on the blood smear of 8% of cats. Clinical evidence of hemorrhage was seen in 15% of cats and included petechiae, ecchymoses, hemothorax hemoabdomen rectal bleeding epistaxis and hematuria.

Of the 43 cats studied, 5 died or were euthanized within 2 weeks of discharge from the hospital. Only 3 cats with DIC survived and the longest survival in this group of cats was 1 year. The underlying disorders in these 3 cats were not reported. The remaining 38 cats were euthanized or died before discharge from the hospital.

The authors conclude DIC is a disorder which carries an extremely poor prognosis in the cat and treatment should focus on management of the underlying disorder.

Speaker Information
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Ann E. Hohenhaus, DVM, DACVIM (Oncology and Internal Medicine)
The Animal Medical Center

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