Hyperlipoproteinemia natural history, complications and prognosis

# Overview
Hyperlipidemia may be inherited or secondary to some underlying disorder. Without treatment, it progresses to cause cardiovascular and cerebrovascular diseases. However, early detection and aggressive management to lower the blood lipid levels helps prevent complications. In addition, some forms may predispose to acute pancreatitis.

# Natural History
Hyperlipidemia may be inherited or secondary to some underlying disorder. High levels of LDL-cholesterol in hyperlipidemia increase cholesterol uptake in non-hepatic cells where monocytes and macrophages engulf cholesterol particles, leading to formation of foam cells and atherosclerotic plaque in the endothelium of arteries, leading to development of symptoms of coronary artery disease or cerebrovascular disease. Cholesterol also accumulates in other areas, such as the skin, causing xanthelasmas and the tendons, causing variety of xanthomas. Early corneal arcus is also common. Without treatment, the patient will also develop valvular abnormalities, most frequently aortic stenosis, due to the deposition of cholesterol.

# Complications
Complications that can develop as a result of hyperlipidemia are:
- Coronary heart disease - This is the end result of the accumulation of atheromatous plaques within the walls of the arteries that supply the myocardium (the muscle of the heart) with oxygen and nutrients. While the symptoms and signs of coronary heart disease are noted in the advanced state of disease, most individuals with coronary heart disease show no evidence of disease for decades as the disease progresses before the first onset of symptoms, often a "sudden" heart attack, finally arise.
- Cerebrovascular disease - The incidence of artherosclerosis of the major intra- and extracranial vessels of the brain increases with increasing levels of serum cholesterol. Hypercholesterolemia is a key risk factor for ischemic stroke.
- Carotid artery stenosis - This is when there is narrowing of the lumen of the carotid artery, usually by atheroma (a fatty lump or plaque causing atherosclerosis), which may cause transient ischemic attacks (TIAs) and cerebrovascular accidents (CVAs) as it obstructs the bloodstream to the brain. It also has the potential to generate emboli (blood clots) that obstruct the cerebral arteries.
- Peripheral arterial disease - This is caused by the obstruction of large peripheral arteries resulting from atherosclerosis, which leads to acute or chronic ischemia (lack of blood supply), typically of the legs.
- Valvular abnormalities - Can lead to causing aortic stenosis
- Abdominal aortic aneurysm - This is a localized dilatation of the abdominal aorta, that exceeds the normal diameter by more than 50%, which is caused by a degenerative process of the aortic wall. However, the exact correlation with hyperlipidemia is unknown.

# Prognosis
Hyperlipidemia is often preventable and treatable. Early detection and aggressive management to lower the blood lipid levels helps prevent or slows the progression of coronary atherosclerosis and other complications. If uncontrolled, higher mortality occurs from cardiovascular and cerebrovascular diseases.