Page 578 - Problem-Based Feline Medicine

570 PART 8 CAT WITH ABNORMAL LABORATORY DATA

QUICK REFERENCE SUMMARY
Diseases causing hyperlipidemia
ANOMALY

● Inherited hyperchylomicronemia (p 575)
Domestic shorthair cats. May have no clinical signs, or signs of hyperlipidemia such as lipemia retinalis,
xanthomata or peripheral neuropathy. Caused by a breed-related defect in lipoprotein lipase (LPL) acti-
vation due to a point mutation in the gene for LPL.

● Cholesterol ester storage disease (p 576)
Siamese < 1 year old, corneal clouding, intermittent diarrhea and vomiting, hepatomegaly.
Lysosomal acid lipase (cholesterol ester hydrolase) deficiency results in accumulation of choles-
terol esters in lysosomes.
METABOLIC
● Nephrotic syndrome (p 576)
Hypercholesterolemia occurs in the nephrotic syndrome as a sequel to protein-losing nephropathy.
Proteinuria with hypoalbuminemia are classical findings.
● Diabetes mellitus**(p 574)
Hypertrigylceridemia occurs in some cats with diabetes. LPL activity is reduced, but the cause of
the hypertriglyceridemia is likely multifactorial. Hypercholesterolemia may also occur and results
from increased hepatic synthesis of cholesterol.
● Idiopathic hyperlipidemia*** (p 573)
May have no clinical signs, or have signs of hyperlipidemia. Any breed may be affected but
Burmese kittens are over-represented and may present with severe anemia, lethargy and dyspnea.
The cause of many cases of hyperlipidemia will be unconfirmed. The cause in most of these cases
is due to a so far unidentified defect in lipid metabolism.

INTRODUCTION Lipid metabolism

Medium- and short-chain fatty acids are bound to albu-
MECHANISM min and transferred from the intestine directly to the
liver via the portal vein.
Definition of terms
Cholesterol and triglycerides are insoluble in plasma
Hyperlipidemia is an increase in the plasma trigly- and their transport through the bloodstream relies upon
ceride and/or cholesterol concentrations. their incorporation into specialized lipid–protein com-
plexes called lipoproteins.
Hyperlipidemia may result from a primary defect in
lipoprotein metabolism or from lipoprotein metabolism There are four classes of lipoproteins (chylomicrons,
being altered by systemic disease. VLDL, LDL and HDL), each with separate physical
and chemical characteristics.
Lipemia is the lactescent appearance of plasma and
indicates an increase in the plasma triglyceride concen- Each of the four lipoprotein classes have discrete roles
tration in chylomicrons and/or low-density lipoproteins. in plasma lipid transport.