Page 560 - Cote clinical veterinary advisor dogs and cats 4th

252 Diabetes Mellitus

• Susceptibility may be associated with immune • Inflammatory mediators ○ Hyperthyroidism (cats)
response genes. • Disorders of insulin receptor and intracellular ○ Chronic kidney disease (not normally
VetBooks.ir RISK FACTORS HISTORY, CHIEF COMPLAINT • Other causes of polyphagia (p. 809) and
associated with increased appetite)
signaling
weight loss (p. 1047)
• Cats: odds of developing DM increase
with body weight > 4 kg, when cats are
include polyuria, polydipsia, polyphagia, and/
overweight or obese, with glucocorticoid • Common complaints of uncomplicated DM Initial Database
or progestogen administration, and with or weight loss. • CBC, biochemical profile and urinalysis to
hypersomatotropism/acromegaly (p. 17) or ○ Blindness (dogs) or gait changes (cats) evaluate for DM and concurrent disease
hyperadrenocorticism (p. 485) may reflect complications of DM. • Per Project ALIVE, DM defined by
• Dogs: unspayed female dogs at risk for • Owners should be questioned about previous ○ In dogs, persistently increased fasting
diestrus-induced DM; dogs with hyperad- or current medical conditions, including (minimum, 8 hours) hyperglycemia (blood
renocorticism and pancreatitis also at risk administration of diabetogenic drugs. glucose [BG] > 144 mg/dL) or a single
• DKA presents with inappetance or anorexia, measurement of hyperglycemia with
GEOGRAPHY AND SEASONALITY vomiting, signs of weakness and dehydration, concurrent glucosuria and/or elevated
Canine DM occurs year-round but is more and/or hypovolemia (p. 254). concentrations of glycated blood proteins
frequently diagnosed at the end of winter. • With the exception of DKA, DM does not and compatible clinical signs of DM with
cause inappetance; inappetance without DKA no other plausible cause
ASSOCIATED DISORDERS suggests presence of a concurrent disease. ○ In cats, one or more measurements of
• Primary disease processes underlying the DM • Underlying disease process(es) causing DM hyperglycemia (BG > 126 mg/dL) and an
(see etiologic classification below) can result in additional clinical signs (e.g., elevated concentration of glycated blood
• Diabetic ketoacidosis (DKA), mostly with acromegaly can cause heart failure, hyper- proteins
untreated DM or when concurrent disease adrenocorticism could cause dermatologic • A glycated protein concentration within
is present (p. 254) changes, pancreatitis could cause inappetance the reference interval does not rule out
• Diabetic neuropathy (mostly cats) (p. 808) and abdominal pain). DM. Diagnosis of DM can be achieved
• Diabetic cataracts (dogs) (p. 147) • History and physical exam findings are not by demonstration of persistent or worsen-
• Exocrine pancreatic insufficiency (mostly pathognomonic for DM; other common ing hyperglycemia and/or glucosuria on
with canine juvenile DM) (p. 317) clinical conditions should be considered (e.g., follow-up.
• Urinary tract infections (dogs and cats) hyperthyroidism, chronic kidney disease). • Most commonly measured glycated proteins
(p. 232) ○ Fructosamine; reflects average BG con-
PHYSICAL EXAM FINDINGS centrations over the prior 1-3 weeks (p.
Clinical Presentation • Depending on duration of illness and 1345)
DISEASE FORMS/SUBTYPES underlying or concurrent disease processes, ○ Glycosylated hemoglobin: reflects average
Project ALIVE recommends the following pet may be overweight/obese or underweight/ BG concentrations over previous 2-3
etiologic classification; an individual can have emaciated at initial presentation. months (cats) and 3-4 months (dogs)
concurrent underlying causes. • Diabetic neuropathy in some cats and rare (p. 1349)
Insulin-deficient DM (beta-cell-related disor- in dogs, including plantigrade posture
ders): • Approximately 80% of dogs suffer from Advanced or Confirmatory Testing
• Reduced insulin secretion due to diabetic cataracts within 1 year of diagnosis. • Given the diverse nature of underlying and
○ Beta cell destruction related to immune- • The underlying disease process causing the concurrent diseases causing DM, the follow-
mediated disease, exocrine pancreatic DM can result in a variety of additional ing screening tests should be considered:
disease, other causes such as toxicity physical exam findings. ○ Serum IGF-1 for acromegaly (cats)
(diazoxide) or idiopathic causes ○ Serum feline pancreatic lipase immunore-
○ Beta cell death (apoptosis) from gluco- Etiology and Pathophysiology activity (fPLI) or canine pancreatic lipase
toxicity, lipotoxicity, other or idiopathic • Consider the ALIVE etiologic classification immunoreactivity (cPLI) and abdominal
causes of DM at time of diagnosis. ultrasound (for pancreatitis)
○ Beta cell aplasia/abiotrophy/hypoplasia • Type of DM dictates best diagnostic and ○ Urine analysis, sediment, and culture
• Production of defective insulin treatment practice. (urinary tract infections are common in
Insulin-resistant DM (target-organ disorders): diabetic pets)
• Endocrine influences DIAGNOSIS • Screening for other diseases depends on
○ Growth hormone: hypersecretion (i.e., level of suspicion, as well as on a discussion
acromegaly) from pituitary or mammary Diagnostic Overview with the owner about costs and relevance of
origin (p. 17) or exogenous administra- • Step 1: establish whether the clinical signs diseases.
tion. Hypothyroidism can increase growth are compatible with DM
hormone production. • Step 2: documentation of pathologic TREATMENT
○ Steroids: glucocorticoids from hyper- hyperglycemia
secretion (i.e., hyperadrenocorticism • Step 3: exclusion of other diseases/phenomena Treatment Overview
[p. 485]) or exogenous administration; that could lead to hyperglycemia Main treatment goals:
progesterone/progestins from secretion • Step 4: establish type of DM • Resolution of clinical signs of DM along with
(i.e., pregnancy or, in dogs, diestrus) or improvement of pet’s and owner’s quality of
exogenous administration Differential Diagnosis life (QoL)
○ Catecholamines • Stress hyperglycemia (more frequent in cats, • Avoiding complications (hypoglycemia,
○ Thyroid hormone (i.e., hyperthyroidism possible in dogs) (p. 1235) DKA); cataracts are difficult to prevent
[p. 503]) • Other causes of polyuria/polydipsia (p. 812); Considerations in achieving these goals:
• Obesity top differentials to consider: • Treat the underlying condition causing the
• Drugs ○ Hyperadrenocorticism (not normally DM whenever possible.
○ Thiazide diuretics associated with weight loss if occurs • Clinical signs improve or resolve after BG is
○ Beta-adrenergic agonists without DM) maintained < 270 mg/dL most of the time.

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