Hyperlipidaemia

Last updated: Monday, 13, December, 2010
CausesAppropriate Tests

Lipid investigations should be done in patients with a personal or family history of atherosclerosis and patients with disease associated with hyperlipidaemia eg, diabetes mellitus, hypothyroidism, chronic renal disease, xanthomas.

The tests should not be performed on specimens collected between 24 hours and 8 weeks after myocardial infarction, as levels will be lower than usual.

The specimen is collected without venostasis, following a fast of at least 12 hours.

The initial screen is fasting plasma cholesterol and triglycerides, ideally with HDL cholesterol and LDL cholesterol.

Lipoprotein electrophoresis is indicated only if the triglyceride level is >4mmol/L.

Apolipoprotein A1 and B can be measured instead of HDL and LDL cholesterol, but there is no advantage in doing so unless familial hyperapolipoproteinaemia B (normal LDL cholesterol, increased apolipoprotein B) is suspected.

Plasma lipoprotein (a) is an independent risk factor for atherosclerosis and may be indicated in patients with a personal or strong family history of atherosclerosis, with normal LDL and HDL cholesterol.

HypercholesterolaemiaCharacterised by increased LDL (type IIa pattern on lipoprotein electrophoresis).
Inherited
  • Familial hypercholesterolaemia
  • Familial combined hyperlipidaemia
Secondary causes

 


Hypercholesterolaemia is due to lipoprotein X, rather than to elevated LDL; further investigation is not indicated.

Hypertriglyceridaemia

Characterised by increased chylomicrons or VLDL (type I or IV pattern on lipoprotein electrophoresis).

Patients may also have hypercholesterolaemia of chylomicron or VLDL origin, but LDL cholesterol is normal.

Inherited
  • Familial hyperchylomicronaemia
  • Familial hypertriglyceridaemia
  • Familial combined hyperlipidaemia


Post-heparin lipoprotein lipase; apolipoprotein CII - consult pathologist.

Secondary causes

See Alcoholism

Hypercholesterolaemia and hypertriglyceridaemia

Characterised by increased LDL and VLDL, IDL, or VLDL and chylomicrons (type IIb, III, or V patterns respectively on lipoprotein electrophoresis).
Inherited
  • Familial combined hyperlipidaemia
  • Familial dysbetalipoproteinaemia


Apo E phenotyping or genotyping.

Secondary causes