Page 863 - Small Animal Internal Medicine, 6th Edition

CHAPTER 49 Disorders of the Endocrine Pancreas 835

concentrations after consumption of diets containing a high to administer insulin. The current recommendation in this
carbohydrate load and vice versa. Dietary studies in diabetic situation is to feed diets containing increased protein and
VetBooks.ir cats have documented improved control of glycemia with decreased carbohydrate content to the cat rather than
administer glipizide.
diets containing increased protein and decreased carbohy-
Newer antidiabetic medications for the treatment of type 2
drate content, and low-calorie-dense fiber-containing diets.
The central theme in these dietary studies has been restric- diabetes in humans have focused on incretins. Incretins such
tion of carbohydrate absorption by the gastrointestinal as glucagon-like peptide-1 (GLP-1) and glucose-dependent
tract, either by delaying intestinal glucose absorption (fiber) insulinotropic polypeptide (GIP) are gastrointestinal hor-
or decreasing carbohydrate ingestion (low-carbohydrate- mones released in response to food intake that increase
containing diets). Intuitively, the most effective means glucose-dependent insulin secretion, inhibit glucagon secre-
to minimize gastrointestinal absorption of carbohydrates tion, slow gastric emptying, induce satiation, and promote
in the diabetic cat is to feed diets that contain minimal weight loss in humans. A recent pilot study evaluating the
amounts of carbohydrate. Currently, we initially use diets effect of a GLP-1 analogue (Exenatide Extended) in newly
with high protein and low carbohydrate content. If prob- diagnosed diabetic cats concurrently treated with insulin
lems with palatability, satiation, azotemia, or chronic pan- glargine and a low-carbohydrate diet achieved diabetic
creatitis become an issue, or if poor control of glycemia remission or good metabolic control in 40% and 89% of
persists despite adjustments in insulin therapy, a switch to the diabetic cats compared with 20% and 58% in control
one of the low-calorie-dense fiber-containing diets designed diabetic cats, respectively (Riederer et al., 2016). Exenatide
for diabetic cats, or a switch to a more appropriate diet Extended was safe in cats, did not result in weight gain,
that addresses concurrent problems (e.g., a kidney diet in and stimulated insulin secretion. What role, if any, incre-
an azotemic cat or a moderate-protein, highly digestible tin medications may have for the treatment of diabetic cats
diet for chronic pancreatitis) should be considered. Diets remains to be determined. These medications are presum-
with high fat and low carbohydrate content (e.g., growth ably not indicated in dogs because dogs do not develop type
diets) are not recommended because of concerns related to 2 diabetes.
the impact of high dietary fat content on obesity, hepatic
lipidosis, chronic pancreatitis, and insulin resistance— Adjusting Insulin Treatment and Blood
the latter induced by increased circulating concentrations Glucose Monitoring
of nonesterified fatty acids, β-hydroxybutyric acid, and Stress hyperglycemia and diabetic remission are two impor-
triglycerides. tant considerations when monitoring and adjusting insulin
in the diabetic cat. Cats have the propensity to develop
IDENTIFICATION AND CONTROL OF stress-induced hyperglycemia caused by frequent visits to
CONCURRENT PROBLEMS the veterinary hospital for blood samplings. Once stress-
Identification and correction of concurrent disorders that induced hyperglycemia develops, it is a perpetual problem
cause insulin resistance and interfere with the success of and blood glucose measurements can no longer be consid-
insulin therapy is critical to the successful treatment of dia- ered accurate. Veterinarians must remain wary of stress
betes in cats. Examples include obesity; chronic pancreatitis hyperglycemia in diabetic cats and should take steps to
and other chronic inflammatory diseases; infection; and prevent its development. Micromanaging diabetic cats is not
insulin-resistant disease such as hyperthyroidism, hyperad- recommended, and blood glucose curves should be done
renocorticism, and acromegaly. In diabetic cats with partial only when the clinician perceives a need to change insulin
loss of β cells, correction of insulin resistance may result in therapy.
diabetic remission. An evaluation of the diabetic cat for con- In a newly diagnosed diabetic cat, we will initially do an
current problems is indicated at the time diabetes is diag- abbreviated blood glucose curve, measuring blood glucose
nosed and whenever control of glycemia deteriorates in a at the time of the insulin injection and 3 or 4 more measure-
previously well-controlled cat. The initial evaluation should ments during the day, making sure hypoglycemia has not
include a thorough history, physical examination, CBC, occurred, and then send the cat home to be treated by the
serum biochemistry panel, serum thyroxine concentration, client. During this time period, we also talk to the client
urinalysis with culture, and (if available) abdominal about diabetic remission and home blood glucose monitor-
ultrasound. ing. We initially rely on the client’s perception of response
one week after initiating insulin treatment to determine if an
ORAL HYPOGLYCEMIC DRUGS increase in the insulin dose is indicated. If the client believes
Oral hypoglycemic drugs work by stimulating pancreatic the cat is doing well, we will not adjust the insulin dose and
insulin secretion (e.g., sulfonylureas), enhancing tissue sen- evaluate a blood glucose curve a week later. If the client has
sitivity to insulin (e.g., metformin, thiazolidinediones), seen minimal to no improvement in clinical signs, we will
or slowing postprandial intestinal glucose absorption increase the insulin dose one half to one unit per injection
(α-glucosidase inhibitors). Only the sulfonylurea drug glipi- (depending on the size of the cat) and evaluate a blood
zide was marginally effective in diabetic cats and was used glucose curve one week later. The subsequent frequency of
as an alternative treatment for owners who initially refused monitoring and obtaining blood glucose curves depends on