 Let's move on and discuss hyperlipidemia. So hyperlipidemia is an elevation of lipids within the blood. These lipids can be fat, triglycerides, or cholesterol. Some signs that the human body gives to show that their levels of lipids or fats in the body are high include xanthomas. These are classically described as lipid laden histiocytes. And as you see in this picture here, this is a classic presentation of xanthomas, which are plaques or nodules that are on the skin. You can especially see this over extensor surfaces of joints, as well as in the eyelids. If they're in the eyelids, they're known as xanthalasmas. Further signs of hyperlipidemia in the body are tendinous xanthomas. These are lipid deposits that deposit themselves in the tendons of the body. We especially see this present in the Achilles tendon behind the heel. We can also see some corneal arcus. These are lipid deposits in the cornea. We do commonly see these as a normal scuela of aging in the elderly. But if they do appear earlier in life, then that is something that we can see with hypercholesterolemia. You can see those as this hazy white gray circles around the exterior portions of the cornea. Noticing early signs of hyperlipidemia is important to decrease our risk of progressing this hyperlipidemia in the blood to an atherosclerosis. Atherosclerosis is the buildup of cholesterol and plaques in the intima of the blood vessels. As you see here in this diagram, normal blood vessels are open in the middle with no obstructions. As we get them partially blocked with our lipid deposits in the intima, there is going to be a reduction of blood flow within that blood vessel, which can lead to further problems down the road as these blocks continue. The vessels that are most commonly affected by atherosclerosis are elastic arteries that are medium to large size as well as medium to large size muscular arteries. Specifically, this includes the abdominal aorta, the coronary artery, the popliteal artery, the carotid arteries, as well as the circle of willis. The first steps in creating atherosclerotic plaques within a blood vessel wall is endothelial cell dysfunction. As you see on the left, this normal blood vessel wall has some endothelial cells that will dysfunction and they will cause macrophages and LDL or low density lipoproteins to accumulate within the endothelial cells. This is known as a foam cell. Foam cells can continue to grow and become fatty streaks, which will proliferate in the extracellular matrix and cause fibrous plaques to form. Those fibrous plaques can then become complex atheromas that will then undergo calcification and partially block our blood vessels. Some symptoms of atherosclerosis include angina, which is pain in the chest, claudication, which is pain in the extremities, most commonly the lower legs, but often we see patients that are asymptomatic. The atherosclerosis can build up without any symptoms showing, so this is why it is important to be aware of other factors associated with atherosclerosis. Those other risk factors that are associated with atherosclerosis include modifiable and non-modifiable conditions. Modifiable conditions are things that can be changed due to behavior changes within a patient. So smoking is the number one modifiable risk factor for atherosclerosis. We also include hypertension, dyslipidemia, and diabetes under modifiable risk factors. Non-modifiable risk factors are things that we cannot change, such as age. As we increase in age, we have an increased risk of atherosclerosis. Sex is another non-modifiable risk factor for atherosclerosis, specifically male sex. Males have a much higher risk of atherosclerosis, but we also include postmenopausal women as a higher risk for atherosclerosis as well. And finally, family history. If you have a family history of atherosclerosis, you do have an increased risk of developing that yourself. Conditions associated with atherosclerosis include the following, aneurysms, ischemia, infarctions, peripheral vascular disease, or PVD, thrombus, and emboli.