Lipid profile: Making the diagnosis of hyperlipidemia

 Lipid profile: Making the diagnosis of hyperlipidemia 

-hyperipidemia are changes in one or more parameters of lipids in the blood

-Atherogenic disease: ability to produce fatty plaques (also called atheromatous plaques) 

- Practically one or more of the following abnormalities: 4 entities

hypercholesterolemia

hypertriglyceridemia

decreased HDL cholesterol 

increased LDL cholesterol

- It is considered as the main cardiovascular risk factor responsible for atherosclerosis.

 Circumstances of discovery :

-During a biological check-up :

-Systematic biological workup (incident  discovery)

-At the patient's request

-In search of cardiovascular risk factors (in patients already at risk , so we talk about a medical screen test)

-Family screening 

-When a complication occurs :

a cardiovascular event (stroke, TIA ,  myocardial infarction)

Evocative symptoms: Deposits +++

- Intravascular: in the blood vessels

- Extravascular: outside the blood vessels

Xanthomas: cholesterol tumor, yellow-orange color, very variable size. Localized in the : extensor tendons of fingers and toes , achilles tendon , and the extension side of joints.

Xanthelasma: localized in the interner angle of the eye + eyelids

Gerontoxon : ring shaped peri corneal fatty deposit 

Classification: We must distinguish :

a) Primary hyperlipidemia: which includes:

1. Hypercholesterolemia

2. Hypertriglyceridemia

3. Mixed hyperlipidemia

4. Other hyperlipidemia

b) Hyperlipidemia secondary to other reasons:

1. preponderant hypercholesterolemia : Hypothyroidism, Cholestasis, GH deficiency , Anorexia ...

2. preponderant hypertriglyceridemia : Diabetes , Renal insufficiency , HIV , iatrogenic (Alcoholism , Thiazides , B-blockers, Interferon, Ethinyloestradiol . )...

3. hypertriglyceridemia + Cholesterol : Nephrotic Syndrome , Lupus , Iatrogenes ( steroids , retinoic acid )

The diagnosis is confirmed by blood tests (biological tests):

- Blood sample must be taken:

§ After 12 hours of fasting

§ At a distance from an acute disease (2 to 3 months after infection, MI, surgery).

- The standard work up is composed of 4 components:

  CT + TG + HDL + LDL

How to interpret this lab test ?

- In a patient with no risk factors, the following lipid panel would be considered normal:

§ LDL cholesterol < 1.6 g/l (4.1 mmol/l)

§ Triglycerides < 1.5 g/l (1.7 mmol/l)

§ HDL cholesterol > 0.4 g/l (1 mmol/l)

How to treat this type of diseases ?

To get there, you have to follow these steps in an organized way (strictly in order ):

1) Search for secondary hyperlipidemia (we have previously seen the possible reasons ) 

- Medical examination: which aims to find a drug intake, alcoholism ...

- physical examination 

- Complementary examinations include : Fasting blood sugar (FBS), TSH , Creatinine level → systematically = obligatory

§ Other examinations may be requested depending on the clinical context of the patient: 

24 hours  proteinuria,  IGF1...

2. Identification of cardiovascular risk factors in order to classify according to 3 levels of cardiovascular risk: 

Age: Men > 50 years and Women > 60 years or menopausal.

Early CV heredity (MI or sudden death):

§ In Father or 1st degree relative < 55 years of age.

§ Mother or 1st degree relative < 65 years old

Current or discontinued smoking < 3 years.

Permanent hypertension treated or not.

Type 2 diabetes treated or not.

HDL < 0.40 g/l ! 

Note: If HDL levels > 0.60 g/l, subtract one risk factor from the overall score.

The three levels of risk are as follows:

 Low risk:

§ If no other RF is associated with hyperlipidemia .

 Milld risk:

§ If > 1 RFis  associated with dyslipidemia

 High Risk:

 justifies secondary prevention or an equivalent risk

 High risk cardiovascular are:

Patients + history of coronary or vascular disease

Patients with diabetes 2, without vascular history but with high cardiovascular risk defined by

o Renal impairment (proteinuria > 300 mg/24 h or CrCl < 60)

o Or at least 2 of the following risk factors

 age: male > 50 years, female > 60 years

 Family history of early coronary disease: MI or sudden death

 Current smoking or smoking cessation within the last 3 years

 Permanent hypertension treated or not

 HDL-cholesterol < 0,40 g/l whatever the gender

 Microalbuminuria (> 30 mg/24 hours)

4. Treatment of dyslipidemia:

 

The aim of this treatments are to:

- Delay the onset (primary prevention)

- Or recurrence (secondary prevention) of clinical complications of atherosclerosis.

- ↓ LDL: best indicator of effectiveness of cardiovascular prevention. 

- LDL targets: are defined according to cardiovascular risk level  !!!

 Means to treat:

(a) Hygienic-dietary recommendations for each patient :

- Balanced diet, Mediterranean type:

§ ↓ saturated FAs , ↑ mono- or polyunsaturated FAs (low-fat dairy products,

§ ↑ fiber & micronutrient consumption (fruits, vegetables, whole grain bread..)

- Limiting alcohol consumption

- Weight control (target: BMI <25 )

- Regular practice of physical activities.

b) Drug treatment :

 Statins :

Simvastatin (Zocor ® 20-40mg)

Rosuvastatin (Crestor 10 mg-20mg)

Atorvastatin (Lipitor ® 10 mg-20mg)

Statins have an effect on lipidic abnormalities but also on the atheroma plaque .

- Fibrates: Fenofibrate +++ .

- Resins: Colestyramine

- Inhibitor of the intestinal absorption of cholesterol: EZETIMIBE

- Nicotinic acid (nothing to do with nicotine)

D) Monitoring and follow-up :

o Effectiveness: Lipid profile after 3 months

o Tolerance (side effects) :

- liver function test

- Creatine Phosphokinase not systematic: Necessary only if: age > 70 years, renal insufficiency, hypothyroidism, alcohol abuse, unexplained muscle symptoms

In Conclusion :

-These are extremely common conditions, sometimes secondary to a specific cause, but are mostly primary.

- The most frequent hyperlipidémia abnormalities are atherogenic and responsible for cardiovascular diseases, which can be serious !

- The diagnosis and treatment must be methodological, and follow strict and standardized steps .