1- Familial Hypercholesterolemia:
Pure hypercholesterolemia (type IIa):
– This is a LDL overload
– The familial form is autosomal dominant, heterozygous or homozygous (more severe)
– Essential Form polygenic (essential) latent, late complications, mainly depends on the diet
– The two main mechanisms are: lack of LDL receptors (quantitative or qualitative), or by mutation of the apolipoprotein B100
– Deposits extravascular lipid: corneal Arc (gerontoxon) before age 50; xanthelasma (eyelid); xanthomata tendon (tendonitis). Cutaneous xanthomas Tuberous plans and are seen only in the homozygous form.
– Vascular Deposits: early onset of atheroma
– Lipids: increased LDL-ch; increased apolipoprotein B; total cholesterol is> 2.60 g / L; apoprotein A1 may be decreased.
– The goal of treatment is to lower total cholesterol number, but to obtain a normal value in LDL cholesterol
– Rule hygienodietetic correction of overweight, apart from this case the plan must be normocalorique, it must be low in cholesterol (<300 mg / d) and include ⅓ saturated Ag, Ag ⅓ and ⅓ of monounsaturated Ag polyunsaturated.
– Medication: HMG CoA reductase inhibitors (simvastatin, pravastatin) first intension
2- isolated Hypertriglyceridemia:
A- endogenous hypertriglyceridemia (type IV):
– Is due to increased VLDL synthesis by excess carbohydrate intake and / or alcoholic and hyperinsulinism
– The mode of transmission is autosomal dominant
– This anomaly is caused by deficiency of lipoprotein lipase (LPL) or triglyceride lipase => slowing the catabolism of VLDL.
– The triglyceride level is very variable depending on food intake; in the absence of trigger (carbohydrates, alcohol, over-charging weight) triglyceride levels are normal.
– The only dermal deposition observed (in most forms) is the eruptive xanthomatosis. Retinal lipemia (FO: milky serum)
– In the major form, there’s a high risk of acute pancreatitis
– Being overweight is observed in pléthoro-dependent and carbohydrate-dependent forms.
– In the minor form, digestive disorders banal, postprandial somnolence, no lipid deposition; no risk of acute pancreatitis.
– The diet is the only treatment needed (effective and sufficient in 80% of cases). The diet should be normocalorique.If-ing drug trafficking, fibrates are prescribed first intension. Nicotinic acid, ω3 AG.
B- exogenous hypertriglyceridemia (type I):
– Hyperchylomicronemia (very rare) by absence of lipoprotein lipase and apo CII (autosomal dominant)
– The level of triglycerides is variable depending on food intake, in the absence of fat absorption, the level of triglycerides is normal. Minimal absorption of fat causes serious outbreaks
– The clinical signs are similar to those observed in the type IV (major form) apart from the constant absence of obesity.
– The serum is milky fasting; overload chylomicrons; triglycerides are very high (> 10 g / l); total cholesterol is normal
– Never cause atherosclerotic complications, the major risk is acute pancreatitis
– This is the only hyperlipidemia or plan to be very restrictive in fat (<20% of total energy intake: 10 to 15 g / d).
Medium chain triglycerides is little use (which are absorbed into the portal vein and therefore does not participate in the formation of chylomicrons).
– There is no effective drug treatment
3- Mixed Hyperlipidemia:
A- dysbetalipoproteinemia (type III):
– It is characterized by the accumulation of chylomicron remnants and VLDL (enriched in cholesterol). It is related in part to a defective apoE (E2 allele).
– Cholesterol deposit (to adulthood): Tuberous xanthoma, tubérouréptifs. The presence of yellow to orange xanthomata palmar creases is pathognomonic (50% of untreated subjects). The tendon xanthomas and xanthelasma are less common than in the Ia type.
– 30 to 50% are developed cardiovascular involvement if the treatment is not instituted
– The peculiarity of this disease is the frequency of arterial involvement of members equal or superior to those of coronary.
– Important Elevation (> 3 g / L) and the same order of magnitude of total cholesterol and triglycerides.
– The confirmation is made by highlighting the lipoprotein electrophoresis (agarose gel) to a broad-band beta which cor-responds to beta-VLDL (corresponds to chylomicron remnants and VLDL) and IDL and migrates between the band of VLDL and those of LDL.
B- familial combined hyperlipidemia (type IIb):
– This is the association of a type IIa hypercholesterolemia Type IV hypertriglyceridemia. It depends on the diet and is highly atherogenic.
– Increased apoB100 and therefore products of VLDL by the liver and are turned into LDL (addition of VLDL and LDL)
– Its prevalence is high (1/200). She unmasks after the age of 25 years.
– Total cholesterol and triglycerides are increased; apoprotein B is high
– The lipoprotein electrophoresis shows an increase of beta and pre-beta lipoproteins
– The type IIb hyperlipoproteinemia is the most atherogenic of hyperlipoproteinemias. Ischemic stroke at the age of 35 years. The peripheral arterial disease is very common.
– Low Calorie Diet; limit sugars with high glycemic index, remove alcohol …
– Fibrates are in first intension
C- Other dyslipidemia:
This is a decrease in HDL cholesterol, very common and often associated with other lipid disorders, especially hypertriglyceridemia. There are also family forms Tangier disease (by structural abnormality of Apo A1); deficiency in ALCAT …
b- endocrine Dyslipidemia:
– Diabetes mellitus (relative or absolute insulin deficiency) with high triglycerides and HDL-ch lowered
– Hypothyroidism: hypercholesterolemia often
– Other: hypercortisolism (mostly cholesterol); acromegaly (hypertriglyceridemia) hypopituitarism.
c- Other causes of secondary dyslipidemia:
– Nephrotic syndrome (increased all lipoprotein classes
– Renal failure
– Cholestasis (hypercholesterolemia related to the presence of abnormal lipoprotein Lp X)
– Advanced Liver failure (decrease HDL)
– Drugs: beta blockers, retinoids, corticosteroids, oral contraceptives