Hypertension-Related Vascular Changes
Hypertension (HTN) accelerates atherosclerosis and causes distinct, predictable damage to small arteries and arterioles. Understanding these morphological changes is essential for pathology board examinations.
1. Arteriolar Damage: Two Classic Patterns
| Lesion | Pathological Features |
|---|---|
| Hyaline Arteriolosclerosis | Caused by benign (chronic) HTN. Protein leakage into the vessel wall creates a pink, glassy (hyaline) thickening. Leads to luminal narrowing and ischemia (e.g., nephrosclerosis). |
| Hyperplastic Arteriolosclerosis | Caused by severe/malignant HTN. Features an “onion-skin” appearance due to smooth muscle cell proliferation and basement membrane duplication. |
2. Exam Must-Knows
- Malignant Hypertension: Defined by a rapid rise in BP (>180/120 mmHg) with end-organ damage (e.g., papilledema, acute renal failure). Hyperplastic arteriolosclerosis is the hallmark.
- Fibrinoid Necrosis: Often associated with hyperplastic arteriolosclerosis in malignant HTN; involves vessel wall necrosis and inflammation, which may lead to vessel rupture and hemorrhage.
- Diabetes Mellitus Link: Hyaline arteriolosclerosis is also seen in diabetes, as chronic hyperglycemia causes similar endothelial dysfunction and plasma protein extravasation.
3. Clinical Correlation
Pathology Pearl: The kidney is the most frequent target of both hyaline and hyperplastic changes. Chronic benign hypertension leads to diffuse cortical atrophy and a granular surface (benign nephrosclerosis), while malignant hypertension causes “flea-bitten” petechial hemorrhages due to fibrinoid necrosis of arterioles.