Pretreatment clinical and laboratory evaluation of cats with diabetes mellitus: 104 cases (1992-1994).

To assess pretreatment clinical and laboratory findings in cats with diabetes mellitus and to determine the influence of ketoacidosis on pretreatment findings. Retrospective case series. 104 cats with diabetes mellitus, 38 of which had ketoacidosis. Medical records of cats with diabetes mellitus examined over a 20-month period were reviewed. Cats that had received previous treatment for diabetes mellitus, or for which medical records were incomplete, were excluded from this study. Cats ranged in age from 1 to 19 years (median, 11 years). Male cats were twice as likely to develop diabetes as females. The most common historical signs were polyuria, polydipsia, weight loss, and diminished activity. Anorexia or poor appetite was reported more commonly than polyphagia, especially in cats with ketoacidosis. Diminished activity, anorexia, weakness, and vomiting were all significantly more common in ketoacidotic cats than in nonketoacidotic cats. Forty-four cats were considered thin, and 34 were considered obese. All cats had hyperglycemia and most had hypercholesterolemia and high activities of 1 or more hepatic enzymes. Compared with nonketoacidotic cats, ketoacidotic cats were more likely to have had low serum electrolyte values. All cats had glucosuria and 42 (40.4%) had ketonuria. Baseline serum insulin concentrations were measured in 18 cats and were low or at the low end of the reference range in 14 (77.8%) cats. Serum fructosamine concentration, determined in 22 cats, was high in 20 (90.9%) cats. Twenty-three of the 104 (22.1%) cats had concurrent disease, the most common of which were hyperthyroidism, inflammatory bowel disease, and eosinophilic granuloma complex. In more than a third of cats, diabetes mellitus is complicated by development of ketoacidosis, which increases the severity of clinical and laboratory abnormalities. Diagnosis of diabetes mellitus is made on the basis of signalment (e.g., middle-aged to old male cats), owner complaints (e.g., polyuria, polydipsia, and weight loss), physical examination findings (e.g., lethargy or muscle wasting), and laboratory findings (e.g., hyperglycemia and glucosuria).