Snapshot A 45-year-old woman presents to her primary care physician for a routine visit. She reports feeling very tired over the past few months. She also reports gaining weight over the past year due to physical inactivity and poor dieting habits. She has a 4 pack-year history of smoking. On physical exam, she is overweight but otherwise without any abnormal findings. Given her risk factors, her physician recommends a screening lipid panel as well as thyroid function tests. SUMMARY Clinical definition elevated serum levels of cholesterol parameters are total cholesterol, low-density lipoprotein (LDL), and high-density lipoprotein (HDL) Epidemiology risk factors obesity smoking hypertension family history older age Etiology Etiology familial hypercholesterolemia physical inactivity metabolic syndrome diabetes chronic kidney disease hypothyroidism drugs steroids protease inhibitors Pathogenesis hypercholesterolemia results from excess cholesterol from the diet, bile, or intestines triglycerides enter the plasma from the liver (as very low-density lipoproteins, VLDLs) or intestines (as chylomicrons) VLDLs are converted into LDLs cells with LDL receptor then receive cholesterol from LDLs HDL carries extra cholesterol back to the liver to be metabolized Associated conditions diabetes hypertension hypertriglyceridemia atherosclerosis Presentation Symptoms typically asymptomatic Physical exam metabolic syndrome high blood pressure in severe cases, may see xanthomas login to view 1 more bullet xanthelasma login to view 1 more bullet corneal arcus login to view 1 more bullet Studies Labs fasting lipid panel total cholesterol login to view 1 more bullet LDL cholesterol login to view 1 more bullet HDL cholesterol triglycerides rule out secondary causes of hyperlipidemia fasting blood glucose hemoglobin A1c thyroid stimulating hormone alkaline phosphatase urinalysis login to view 1 more bullet Making the diagnosis based on laboratory studies Differential Hypothyroidism distinguishing factors abnormal thyroid function tests often presents with other symptoms of hypothyroidism, including weight gain, cold intolerance, and lethargy Treatment Management approach screening men at 40 years of age women at 50 years of age men and women 20 years of age with risk factors for coronary artery disease (CAD) family history of familial hypercholesterolemia target numbers low-density lipoprotein < 100 mg/dL login to view 1 more bullet high-density lipoprotein ≥ 40 mg/dL triglycerides <150 mg/dL Conservative dietary modification indication login to view 1 more bullet modalities login to view 1 more bullet increased physical activity indication login to view 1 more bullet Medical statins indications login to view 5 more bullets side effects login to view 1 more bullet ezetimibe indication login to view 1 more bullet PCSK9 inhibitors indications login to view 1 more bullet drugs login to view 2 more bullets Complications Heart disease Prognosis associated with ↑ risk of cardiovascular disease