Chronic kidney disease (CKD) and degenerative joint disease are both considered common in older cats. Information on the co-prevalence of these two diseases is lacking. This retrospective study was designed to determine the prevalence of CKD in two cohorts of cats: cats randomly selected from four evenly distributed age groups (RS group) and cats recruited for degenerative joint disease studies (DJD group), and to evaluate the concurrence of CKD and DJD in these cohorts. The RS group was randomly selected from four age groups from 6 months to 20 years, and the DJD group comprised cats recruited to four previous DJD studies, with the DJD group excluding cats with a blood urea nitrogen and/or serum creatinine concentration >20% (the upper end of normal) for two studies and cats with CKD stages 3 and 4 for the other two studies. The prevalence of CKD in the RS and DJD groups was higher than expected at 50% and 68.8%, respectively. CKD was common in cats between 1 and 15 years of age, with a similar prevalence of CKD stages 1 and 2 across age groups in both the RS and DJD cats, respectively. We found significant concurrence between CKD and DJD in cats of all ages, indicating the need for increased screening for CKD when selecting DJD treatments. Additionally, this study offers the idea of a relationship and causal commonality between CKD and DJD owing to the striking concurrence across age groups and life stages.

A 4-y-old neutered male German Shepherd Dog was presented with a 3-d duration of lethargy, restlessness, and vomiting. Physical examination revealed generalized lymphadenopathy, pale mucous membranes, systolic heart murmur, dehydration, and fever. Hematologic abnormalities included moderate-to-marked leukocytosis, characterized by neutrophilia with a left shift to progranulocytes and 2% presumptive myeloid blasts, marked anemia that was nonregenerative, and marked thrombocytopenia. Dysplasia was evident in neutrophils and platelets. Bone marrow examination revealed marked myeloid and megakaryocytic hyperplasia with 7% blasts, erythroid hypoplasia, and trilineage dysplasia. Flow cytometric analysis confirmed that bone marrow cells were mostly of neutrophil lineage, with reduced expression of common leukocyte antigens (CD45, CD18) and neutrophil-specific antigen. Bone marrow cells were cytogenetically analyzed for the breakpoint cluster region-Abelson oncogene using multicolor fluorescent in situ hybridization. The genetic aberration was present in 7% of cells, which was a negative result (>10% of cells is considered positive). Euthanasia was elected. Histologic examination showed extensive infiltration of multiple organs by neoplastic myeloid cells, with effacement of lymph node and splenic architecture. The final diagnosis was atypical chronic myeloid leukemia (aCML), an uncommon myeloproliferative disorder with features of myelodysplastic syndromes (dysplasia) and chronic leukemia (neutrophilic leukocytosis with <20% marrow blasts, extramedullary infiltrates). The trilineage dysplasia, lack of monocytosis, and supporting cytogenetics distinguish aCML from CML, chronic neutrophilic leukemia, and chronic myelomonocytic leukemia.