Page 839 - Small Animal Internal Medicine, 6th Edition

CHAPTER 49 Disorders of the Endocrine Pancreas 811

Diagnosis
The diagnosis of diabetes mellitus is based on three findings: BOX 49.4
VetBooks.ir appropriate clinical signs, persistent fasting hyperglycemia, Clinicopathologic Abnormalities Commonly Found in
and glycosuria. Measurement of the blood glucose concen-
Dogs and Cats With Uncomplicated Diabetes Mellitus
tration using a portable blood glucose–monitoring device
and testing for the presence of glycosuria using urine reagent Complete Blood Count
test strips (e.g., KetoDiastix) provide rapid confirmation of Typically normal
diabetes mellitus. Concurrent documentation of ketonuria Neutrophilic leukocytosis, toxic neutrophils if pancreatitis
establishes a diagnosis of diabetic ketosis (DK), and docu- or infection present
mentation of metabolic acidosis establishes a diagnosis of Biochemistry Panel
DKA.
It is important to document both persistent hyperglyce- Hyperglycemia
mia and glycosuria to establish a diagnosis of diabetes mel- Hypercholesterolemia
Hypertriglyceridemia (lipemia)
litus because hyperglycemia differentiates diabetes mellitus Increased alanine aminotransferase activity (typically
from primary renal glycosuria, and glycosuria differentiates <500 IU/L)
diabetes mellitus from other causes of hyperglycemia (see Increased alkaline phosphatase activity (typically
Box 49.1), most notably epinephrine-induced stress hyper- <500 IU/L)
glycemia that may develop around the time of blood sam-
pling. Stress-induced hyperglycemia is a common problem Urinalysis
in cats and occasionally occurs in dogs, especially those that Urine specific gravity typically > 1.025
are very excited, hyperactive, or aggressive. The reader is Glycosuria
referred to page 837 for more information on stress-induced Variable ketonuria
hyperglycemia. Proteinuria
Bacteriuria
Documenting an increase in the serum fructosamine
concentration supports the presence of sustained hypergly- Ancillary Tests
cemia; however, a serum fructosamine concentration in the Serum Spec cPL or fPL normal or increased if pancreatitis
upper end of the reference range can occur in symptomatic present
diabetic dogs if the diabetes developed shortly before pre- Serum lipase normal or increased if pancreatitis present
sentation of the dog to the veterinarian. The reader is referred Serum trypsin-like immunoreactivity (TLI)
to page 818 for more information on serum fructosamine. Low if pancreatic exocrine insufficiency present
A thorough evaluation of the dog’s overall health is rec- Normal or increased if pancreatitis present
ommended once the diagnosis of diabetes mellitus has been Baseline serum insulin concentration
established to identify any disease that may be causing or IDDM: low, normal
contributing to the carbohydrate intolerance (e.g., hyperad- NIDDM: low, normal, increased
Insulin resistance induced: low, normal, increased
renocorticism), that may result from the carbohydrate intol-
erance (e.g., bacterial cystitis), or that may mandate a IDDM, Insulin-dependent diabetes mellitus; NIDDM, non–insulin-
modification of therapy (e.g., pancreatitis). The minimum dependent diabetes mellitus; Spec cPL, canine pancreatic-specific
laboratory evaluation should include a CBC, a serum bio- lipase; Spec fPL, feline pancreatic-specific lipase.
chemistry panel, measurement of serum pancreatic lipase
immunoreactivity, and urinalysis with bacterial culture.
Serum progesterone concentration should be determined if correlated with the severity and duration of hyperglycemia.
diabetes mellitus is diagnosed in an intact bitch, regardless In the diabetic dog, control of hyperglycemia can be estab-
of her cycling history. If available, abdominal ultrasound is lished with insulin, diet, exercise, prevention or control of
indicated to assess for pancreatitis, adrenomegaly, pyometri- concurrent insulin antagonistic diseases, and discontinua-
tis in an intact bitch, and abnormalities affecting the liver tion of medications that cause insulin resistance. The veteri-
and urinary tract (e.g., changes consistent with pyelonephri- narian should also guard against the dog developing
tis or cystitis). Measurement of baseline serum insulin con- hypoglycemia, which is most apt to occur as the result of
centration or an insulin response test is not routinely done. overzealous insulin therapy. The veterinarian should balance
Additional tests may be warranted after the history is the benefits of tight glucose control obtainable with aggres-
obtained, the physical examination is performed, or ketoaci- sive insulin therapy against the risk of hypoglycemia.
dosis is identified. Potential clinical pathologic abnormalities The second goal is to minimize the impact of therapy on
are listed in Box 49.4. the owner’s lifestyle. A recent study evaluated the psycho-
logical and social impact of diabetes and its treatment on the
Treatment quality of life of owners of diabetic dogs (Niessen et al.,
The primary goal of therapy is elimination of client-observed 2012). The top 10 negative impact items were associated
clinical signs of diabetes. Persistence of clinical signs and mostly with the owner’s quality of life rather than the pet’s
development of chronic complications (Box 49.5) are directly quality of life (Table 49.2). Awareness of the impact of the