Hyperlipidemia
Definitions:
Dyslipidemia: a broad term describing disorders of lipoprotein metabolism, including overproduction or deficiency.
Hyperlipidemia: a condition characterized by ↑ serum levels of total cholesterol, low-density lipoprotein cholesterol (LDL), or non-high-density lipoprotein cholesterol (HDL).
Atherosclerotic cardiovascular disease (ASCVD): acute coronary syndromes, history of myocardial infarction (MI), stable angina, coronary, or other arterial revascularization, stroke, transient ischemic attack (TIA), Peripheral artery disease (PAD) of atherosclerotic origin.
Types:
Familial:
Secondary:
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Endocrine disorders: hypothyroidism, DM, Cushing’s syndrome.
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Renal disorders: nephrotic syndrome, uremia.
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Chronic liver disease.
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Medications: glucocorticoids, estrogen, thiazide diuretics, blockers, isotretinoin.
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Pregnancy.
High HDL= Negative risk factor for CAD.
Study guide:
Risk factors:
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Age: Cholesterol levels increase with age until the age 65.
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Physical inactivity.
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Metabolic syndrome (Figure1).
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Family history of hyperlipidemia.
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DM type II.
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Medications (mentioned above).
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Gender:
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Men > women before menopause.
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Men ≤ women after menopause.
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Diet:
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High calorie diet (simple sugars) -> increases triglyceride (TG).
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Saturated fatty acids -> increase LDL and cholesterol.
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Diagnosing criteria
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Large waist circumference — a waistline that measures at least 35 inches (89 centimeters) for women and 40 inches (102 centimeters) for men
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High triglyceride level — 150 milligrams per deciliter,(mg/dL), or 1.7 millimoles per liter (mmol/L), or higher of this type of fat found in blood
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Reduced high-density lipoprotein (HDL) cholesterol — less than 40 mg/dL (1.04 mmol/L) in men or less than 50 mg/dL (1.3 mmol/L) in women of this "good" cholesterol
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Increased blood pressure — 130/85 millimeters of mercury (mm Hg) or higher
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Elevated fasting blood sugar — 100 mg/dL (5.6 mmol/L) or higher
Pathophysiology:
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Sources of TG:
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Intestines produce -> chylomicrons through lymphatic system.
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Liver produces -> very low density lipoprotein VLDL.
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In the blood stream, TG in chylomicrons and VLDL are degraded by lipoprotein lipase into free fatty acids -> stored in tissues (e.g. adipose tissue).
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Chylomicron remnants are endocytosed by the liver.
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LDL, carrying cholesterol, is endocytosed by hepatic and extrahepatic tissues.
Diagnosis:
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Diagnostic criteria:
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2 fasting lipid panels on 2 separate visits with abnormal results.
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For excluding secondary causes:
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Thyroid stimulating hormone (TSH) (hypothyroidism)
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Liver function test (LFTs) (chronic liver disease)
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Blood urea nitrogen (BUN), Cr, urinary proteins (nephrotic syndrome)
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Glucose levels (DM)
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Screening:
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Adult:
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Men ≥35 Y/O
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Women≥45 Y/O
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Children (if any of the following are present):
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Family history of familial hyperlipidemia.
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Family history of premature CAD.
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Obesity.
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Clinical Presentation:
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Mostly asymptomatic.
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In severe hyperlipidemia may present with:
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Xanthelasma (yellow plaques on eyelid).
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Xanthoma (irregular yellow nodule found on tendons).
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Pancreatitis (hypertriglyceridemia).
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CVS Risk Assessment:
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Smoking
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HTN
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Low HDL<35mg\dL
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Age M>45, F>55
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Male gender
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Family history of
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premature CAD
CVS Risk Equivalent:
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DM
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Peripheral arterial disease
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Abdominal aortic
aneurysm -
Carotid artery
disease -
Clinical coronary
artery disease
Management:
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According to ATP IV guidelines, LDL goals are:
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≤ 1 CVS risk factor < 160 mg/dL
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≥ 2 CVS risk factors < 130 mg/dL
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CVS risk equivalent:
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If one diagnosis < 100 mg/dL
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If two diagnoses < 70 mg/dL
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Non-pharmacological treatment:
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Diet control.
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Smoking cessation.
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Exercise.
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Pharmacological treatment:
Complications:
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Atherosclerosis significantly increases risk of developing cardiovascular disease:
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Chest pain
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Heart attacks
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Strokes
References:
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Howland, Richard D et al. Pharmacology. Philadelphia: Lippincott Williams & Wilkins, 2006. Print.
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Fischer, Conrad. Master The Boards. Print.
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Agabegi, Steven S, Elizabeth D Agabegi, and Adam C Ring. Step-Up To Medicine. Philadelphia: Wolters Kluwer/Lippincott Williams & Wilkins, 2013. Print.
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Mayoclinic.org,. 'High Cholesterol - Mayo Clinic'. N.p., 2015. Web. 3 Nov. 2015.
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At a glance, ATP III. 'ATPIII At A Glance A Quick Desk Reference'. NHLBI. N.p., 2015. Web. 3 Nov. 2015.
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Uspharmacist.com,. 'Uspharmacist.Com > Metabolic Syndrome: Risk Factors And Recommendations'. N.p., 2015. Web. 3 Nov. 2015. (Figure1)
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Organiconline.com.sg,. 'Organic Online Naturalis Xanthelasma Treatment'. N.p., 2015. Web. 3 Nov. 2015. (Figure2)
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Wallpaper222,. '20 Awesome Mac Silver Dawn Eyeshadow Images'. N.p., 2015. Web. 3 Nov. 2015. (Figure3)
Written by: Haifa Al Issa
Reviewed by: Sara Qubaiban
Roaa Amer
Format Editor: Adel Yasky
Bayan Alzomaili
Audio recording:
- Read by: Bayan Alzomili
- Directed by: Rana Alzahrani
- Audio production: Bayan Alzomaili