Managing the chronic diabetic dog and cat (Proceedings)
Diabetes mellitus can be a very frustrating disease to deal with. The typical diabetic animal referred to a specialist in internal medicine is invariably difficult to control, insulin resistant, prone to ketoacidosis and/or hypoglycemia, and usually has concurrent diseases that complicate therapy. Much of the veterinary literature regarding the management of diabetes concentrates on anticipating and dealing with the difficult to control patient, and emphasizes the problems that can be encountered with a less than ideal approach to therapy. However, although there certainly is an ideal approach to stabilizing and managing diabetes, this approach is often relatively expensive, and can be inconvenient for the average practitioner who does not have the level of support provided by a teaching hospital.
Fortunately, a good number of the diabetic patients seen by general practitioners seem to do well for many years despite extremely minimalistic management approaches, approaches that are dictated by the real world of economic compromise, difficult owners, recalcitrant patients and (sometimes) veterinary ignorance. Many diabetics can be managed with simple therapy.
Meticulous ApproachAlthough obviously every patient is different, most non-ketoacidotic diabetics are approached in approximately the same fashion. For the purposes of treatment, ketoacidosis is defined as ketonuria and lethargy, anorexia and/or vomiting. Animals with ketones in their urine that are bright, eating well and not vomiting are treated in the same way as non-ketoacidotic patients.
1. Initial Diagnostic Work-up
Search for concurrent illnesses via history, physical examination, hematology, serum biochemistry, urinalysis and urine culture, and consider, based on the results of these results, other tests such as chest and/or abdominal radiography.
2. Commence Dietary Management and Insulin (or Oral Hypoglycemic) Therapy
With canine diabetics, deal with any complicating problems identified during the initial work-up, and then send home on once daily subcutaneous lente (or intermediate-acting) insulin (typically, human recombinant insulin brands such as Humulin® or Novolin® L or N have been used but, since availability of some these products has been steadily drying up, the veterinary pork insulin brand Vetsulin® was, until recent availability issues of its own, the best starting insulin for dogs) at a low dose (0.5 U/kg) each morning for one week. At the same time, commence and consistently adhere to a strict dietary protocol, with one third of the dog's food given prior to insulin, and the other two thirds given eight hours later. Feed a canned high fiber diet to dogs in normal to fat body condition, and a high quality canned dog food to thin dogs. Calculate, based on ideal body weight, the amount of high fiber diet needed for weight reduction in obese dogs.
With feline diabetics, also deal with any problems identified during the initial work-up, and then send home either on insulin or an oral hypoglycemic agent such as glipizide. Cats that are underweight, unwell, or recovering from an episode of ketoacidosis are probably best started on insulin straight away, while dietary therapy and glipizide alone may be appropriate for more stable, heavier cats. Cats have typically received either subcutaneous ultralente insulin such as the human recombinant insulin products Humulin or Novolin U® (but, again, in the US, availability is becoming limited) or, until recent problems with availability,, the veterinary beef PZI insulin provided through Idexx (standard lente insulin is too short-acting for once daily use in cats) at a low starting dose of 0.5 U/kg each morning, or subcutaneous lente insulin (Humulin® or Novolin® L or N, or Vetsulin®) or the new human product insulin glargine (Lantus®, see More Recent Therapies section below) at 0.5 U/kg twice daily, or oral glipizide at a starting dose of 2.5 mg orally twice daily. At the same time, commence a strict dietary protocol, especially in those cats receiving insulin, with one third of the daily food requirements given prior to the morning insulin injection if the cat is eating canned food, and the remaining two thirds given eight hours later. Since cats tend to graze dry food, in those cats that are eating predominantly dry food the food is usually given ad lib. Standardly, it has been recommended to feed a high fiber diet to cats in normal to fat body condition, and a high quality canned or dry food to thin cats. However, more recently, a high protein diet has also been shown to be beneficial in the management of feline diabetes. Several commercial high protein dry and canned cat diets designed specifically for diabetic patients are now available. In obese cats, calculate, based on ideal body weight, the exact amount of food needed for weight reduction.