Atherosclerosis vs. arteriosclerosis
Arteriosclerosis is the general term for hardening and loss of elasticity of arterial walls, while atherosclerosis is its most common subtype, caused by lipid-rich plaques building up in the arterial intima.
Arteriosclerosis and atherosclerosis are related but not interchangeable. Arteriosclerosis is the umbrella term for any thickening, hardening, and loss of elasticity of arterial walls. Atherosclerosis is one specific type — the most common and clinically important — defined by the buildup of lipid-laden plaques (atheromas) in the intima, the innermost layer of the artery.
An atheroma begins with endothelial injury, which allows LDL cholesterol to accumulate and become oxidized in the intima. Macrophages ingest the lipid and become foam cells, forming fatty streaks that progress to fibrous plaques with a lipid core and fibrous cap. Atherosclerosis favors large and medium-sized elastic and muscular arteries — the abdominal aorta, coronary arteries, popliteal arteries, and carotids — and its complications (plaque rupture, thrombosis, embolism) underlie myocardial infarction, ischemic stroke, and peripheral arterial disease.
Arteriosclerosis includes two other patterns tested alongside atherosclerosis. Arteriolosclerosis affects small arteries and arterioles, appearing as hyaline thickening (associated with hypertension and diabetes) or hyperplastic "onion-skinning" (associated with severe hypertension). Mönckeberg medial calcific sclerosis is calcification of the media of muscular arteries; it typically does not narrow the lumen and is usually clinically insignificant.
This compare-and-contrast is a classic USMLE Step 1 pathology point. Be ready to match each subtype to its vessel size, wall layer, associated conditions, and clinical consequences — the details covered in Achievable's cardiovascular pathology chapter.
Key takeaways
- Arteriosclerosis is the general term for arterial hardening; atherosclerosis is its most common subtype.
- Atherosclerosis is intimal plaque formation driven by endothelial injury, oxidized LDL, and foam cells in large and medium arteries.
- Arteriolosclerosis (hyaline or hyperplastic) affects small vessels and is linked to hypertension and diabetes.
- Mönckeberg sclerosis calcifies the media without narrowing the lumen and is usually clinically insignificant.
- Atherosclerotic complications cause myocardial infarction, ischemic stroke, and peripheral arterial disease.