A five-year-old female neutered Burmese (Swedish and UK origin) was started on a management strategy for allergic dermatitis consisting of short course of 5 mg prednisolone twice daily, rapidly tapering and withdrawn after 3 weeks. This programme was repeated five times over the next 6 years until at 11 years of age the cat received a single injection of methylprednisolone (Depo-Medrol 20 mg i.m.) and, within 5 days, was observed to have polydipsia and polyuria. Home urinalysis (Keto-Diastix, Bayer) revealed glucose (2+) without ketonuria and, at initial veterinary assessment 2 days later the cat weighed 3.2 kg (last recorded weight was 3.5 kg 18 months previously) and had a body condition score of 4 (on a 9 point scale []) with no other significant abnormalities detected on physical examination. Routine serum biochemistry revealed marked hyperglycemia (blood glucose concentration 29.8 mmol/L (reference range 3.9–8.8) and increased fructosamine concentrations (481 µmol/L, 190–340). All other measured parameters were within normal limits. Initial management consisted of a high protein, low carbohydrate diet (Purina DM wet and dry food, fed ad libitum in a ratio of at least 3:1) and twice daily porcine lente insulin (Caninsulin, MSD Animal Health), starting with 1 unit q12 h, started immediately (on day seven after the injection of methylprednisolone). Capillary blood monitoring from the pinna of the ear was commenced using a blood glucose meter calibrated for human blood that is used in cats (Accu-Chek Aviva, Roche UK; feline reference range 2.8–5.5 mmol/L for meter []). Blood glucose was taken prior to insulin injection. On some days glucose was also measured more frequently between insulin injections; for example every 3 h or when hypoglycaemia was suspected). Figure shows all of the results for blood glucose testing for the first 4 months of management. During the first 7 days of testing the mean glucose value was 21 mmol/L. The owner obtained a urine sample, which was delivered to the local veterinary practice, and which revealed a pure growth of an Enterococcus. Given the clinical circumstances, this was suspicious of UTI and was treated with antibiotics by the veterinary surgeon. On day 27, the cat was on porcine lente insulin, 2.5 units insulin q12 h and glucose curves documented clear falls in glucose in response to injections, with a nadir at around 4 h. It was considered that the short duration of insulin action might be a limiting factor in achieving good glycemic control and the cat was started on glargine, an insulin analogue registered for human use. On q12 h glargine (4.5–6.5 units per day; 2–3.5 units per injection; Lantus, Sanofi-Aventis) there appeared to be no difference in the pattern of glucose responses, again limiting the total daily dose of insulin that could be delivered without an unacceptable risk of hypoglycemia. For this reason and, concerned that the chance of β cell recovery was diminishing with increasing duration of hyperglycemia, on day 47 a decision was made to increase the frequency of glargine injections to 8-hourly, with a slight increase total daily dose of insulin (to 5.5–7 units per day; 1.5–2.5 units per injection). The owner performed frequent blood glucose measurements at home. On day 53 the frequency of injections was increased to 6-hourly, with an increase in the total dose (to 7–9 units per day; 1.5–3 units per injection) and the daily insulin dose was tapered from 2 units q6 h on day 64 to 0.25 units q6 h on day 77. Intensive monitoring, often every three hours, on day 67–70 revealed that the lowest blood glucose value was 2.7 mmol/L on days 64 and 67. Although only one blood glucose value of <2.8 mmol/L had been recorded, the owner-physician interpreted the relative hyperglycemia during this period to represent rebound hyperglycaemia, and continued to taper the dose of insulin. On day 62 and 65, the dose of insulin was reduced by 21 and 37 %, respectively; the decrease in dose over this time was otherwise not greater than 20 %. On days 77 and 102, blood glucose levels of 2.7 and 2.1, respectively were recorded and were not followed by hyperglycaemia. From day 77, when the cat was on a total daily dose of 1 unit of glargine, glucose concentrations were mostly within the reference range. However it seemed that insulin was still required to achieve euglycemia, and that requirements to achieve euglycaemia were increasing. On day 95, on 0.5 units q6 h glargine, glucose concentrations were 6–8 mmol/L and a fructosamine concentration was 280 µmol/L, in the middle of the reference range. On day 98 it was noted that the weight had increased to 3.9 kg with a body condition score of 6. The total caloric intake was thereafter restricted to a maximum of 75 g wet and 25 g dry food (Purina DM) and physical activity was increased by playing with the cat several times a day. Within 5 days insulin was withdrawn and 1 month later, a visit was made to the local veterinary surgeon. The fructosamine was 271 µmol/L. Over the following 4 years later the cat has remained insulin-independent and, when glucose concentrations are measured (occasionally) these ranged from 4.6 to 5.1 mmol/L.