Veterinary Medicine - September 2007 - (Page 592)

Hyperlipidemia O P E E R - R E V I E W E D dominal distention, anorexia, seizure activity, lipemia retinalis, and lipemic Diagnostic Tests and Expected Results aqueous humor.1-3 Although clinical for Patients with Hyperlipidemia* signs and history may be consistent with pancreatitis, laboratory data and Diagnostic Test Abnormality imaging studies may fail to support a Gross appearance of plasma Lipemia (> 300–400 mg/dl diagnosis of pancreatitis. Because of or serum* chylomicrons or VLDLs or both) the large size of chylomicrons, severe Chylomicron test** Creamy layer (increased chylomicrons); hyperchylomicronemia (> 1,000 mg/dl) no creamy layer (increased VLDLs); can result in the occlusion of organ creamy layer with turbid plasma (both) blood vessels.1 If the pancreatic vessels Serum triglyceride concentration > 140 mg/dl (dog); > 90 mg/dl (cat) are occluded, subsequent pancreatic ischemia results in a vicious cycle of liSerum total cholesterol concentration > 270 mg/dl (dog); > 150 mg/dl (cat) pase leakage, fatty acid degeneration, Additional tests (ACTH stimulation Varies with clinical disease free radical production, and tissue damor low-dose dexamethasone suppresage with secondary pancreatitis.1 In sion test, thyroid function testing, serum people and animals, sustained hyperpancreatic lipase immunoreactivity) lipidemia is a principal risk factor for Lipoprotein electrophoresis** Not disease-specific developing pancreatitis, and patients Lipoprotein lipase activity* Decreased with diabetes mellitus, that present with pancreatitis should be hypothyroidism, pancreatitis, and evaluated for hyperlipidemia.1,2 familial disease In cats, hyperlipidemia can cause cutaneous lesions and peripheral neu*Source: Whitney MS. Evaluation of hyperlipidemias in dogs and cats. Semin Vet Med Surg (Small Anim) 1992;7:292-300. ropathies. The most common clinical **Source: Ford RB. Clinical management of lipemic patients. Compend Contin Educ Pract Vet 1996;18:1053-1065. finding is cutaneous xanthoma, a painless raised lesion caused by an accumulation of lipid-laden macrophages or foam cells in the skin. 1-3,13,14 Although sites of nerve involvement vary, Horner’s syndrome, tibial nerve paralysis, and radial nerve paralysis are common.2 Increased LDL and VLDL cholesterol are risk factors for atherosclerosis in people.8,15 Dogs and cats are considered resistant to atherosclerosis associated with hypercholesterolemia for two reasons: First, unlike in people, the preponderant circulating lipoprotein in dogs and cats is HDL.9,11 Second, most dogs and cats maintain relatively low LDL concentrations because of unique hepatic metabolism that promotes increased HDL and decreased LDL production.9 Nonetheless, when the cholesterol concentration exceeds 750 mg/dl in dogs and 650 mg/dl in cats, there is a relative increase in the LDL particles that predisposes the animals to atherosclerosis.9 TABLE 3 DIAGNOSIS Consider hyperlipidemia in dogs or cats that present for evaluation of clinical signs compatible with hyperlipidemia or with fasting lipemia (lactescent serum). A variety of diagnostic tests are available. See Table 3 for an overview of the test results that indicate hyperlipidemia. Gross appearance of plasma or serum Gross observation of the serum or plasma may assist in the diagnosis.1,2 The presence of fasting lipemia confirms 592 September 2007 VETERINARY MEDICINE

Table of Contents Feed for the Digital Edition of Veterinary Medicine - September 2007

Contents Letters Leading Off The Veterinary Medicine Interview: Dr. William J. Kay Idea Exchange Practical Matters Salivary Mucoceles in Cates: A Retropspective Study of Seven Cases Hyperlipidemia in Dogs and Cats Purina Insert The Latest Management Recommendations for Cats and Dogs with Nonketotic Diabetes Mellitus CE Form Product Preview Advertiser Index Marketplace/Classifieds Mind Over Miller

Veterinary Medicine - September 2007

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