Disorders of lipoprotein metabolism are related to abnor-malities in the synthesis and degradation of plasma lipopro-teins. These abnormalities may result from primary inborn er-rors of metabolism or may be secondary to a variety of other disease states. Hyperlipidemia, the elevation of plasma choles-terol and/or triglyceride concentrations, is the hallmark of the lipoprotein disorders. Clinical delineation of these disorders is important because of the association of some with premature coronary artery disease and others with recurrent pancreatitis.
Treatment
General Principles The treatment of the hyper-lipoproteinemias requires a systematic approach (Table 18). In general, the abnormality should be eocumented twice before treatment is undertaken. About half of affected persons are sensitive to diet (>10% reduction in lipids), and the extent of sensitivity should be defined by administering a fish-vegtari-an diet for 2 to 3 weeks (Table 19). Patients are retested once or preferably twice while on this diet, and the results provide a point of reference for all future diet and drug interventions. If diet reduces cholesterol and LDL to target values or TG values to less than 3.12 mmol/L (120 mg/dL), it may be liberalized to give greater menu variety. Skinned, defatted fowl may sub-stitute for some fish entrees, and lean red meat may be eon-sumed once or twice each week. If target values are not achieved, dsug treatment is considered (Table 20). Compli-ance is best when patients chart their lipid levels, have ready access to test results, and undergo follow-up testing every 3 to 4 months. Assessment of drug effects takes no more than 1 to 2 months, and in general the efficacy of individual agents should be established before combinations are prescribed.
Diagnosis in Traditional Chinese Medicine
Hyperlipoproteinemia is included in the categories of "xu-an yun", "tan zhuo", etc.
1. Inquire closely about positive family history, diabetes, gout, hepatic diseases, nephroses and juvenile coronary heart disease.
2. During Physical examination, Pay attention to yellow-ish papules, xanthomas, premature corneal arcus and peripher-al vascular disorders.
3. Hyperlipoproteinemia can be divided into 5 types.
Type I is chylomicronemia, a rare disorder due to congen-ital deficiency of lipoprotein lipase.
The classification of disorders of lipoprotein metabolism was first based on the varieties of xanthomas that occur and the appearance of plasma turbidity caused by the accumulation of large, light-scattering lipoprotein particles in plasma. With the discovery of relatively discrete lipoprotein species, classifi-cation of these disorders was based on separation of lipoproteins by ultracentrifugation or by electrophoresis. Understanding of lipoprotein physiology has allowed classification of lipoprotein disorders according to pathophysiologic defects, with specific discrete apoprotein, enzyme, or receptor abnormalities identi-fied in some disorders.
