Chapter 12: Vascular Pathology

Large vessel vasculitis includes Takayasu arteritis, typically affecting the aortic arch in younger patients, and giant cell arteritis, which often presents with headaches and visual disturbances in older adults. Medium vessel disorders include Kawasaki disease, a pediatric condition involving coronary arteries, and polyarteritis nodosa, a necrotizing vasculitis often associated with hepatitis B that typically spares the lungs. The text details small vessel vasculitides, distinguishing between those associated with antineutrophil cytoplasmic antibodies (ANCA)—such as granulomatosis with polyangiitis (formerly Wegener’s) and eosinophilic granulomatosis with polyangiitis (formerly Churg-Strauss)—and immune complex-mediated conditions like IgA vasculitis. Thromboangiitis obliterans, or Buerger’s disease, is highlighted as a smoking-related condition leading to thrombosis and severe extremity pain. Functional disorders are addressed through the differentiation of Raynaud disease, a primary vasospastic disorder, from secondary Raynaud phenomenon caused by underlying systemic conditions like scleroderma. A major portion of the chapter is dedicated to arteriosclerosis, separating the non-inflammatory medial calcification of Mönckeberg sclerosis from arteriolosclerosis, which manifests as hyaline thickening in benign hypertension or diabetes and hyperplastic onion-skinning in malignant hypertension. Atherosclerosis is explored in depth, detailing the progression from fatty streaks to atheromatous plaques, modifiable risk factors like hyperlipidemia and smoking, and complications such as ischemic heart disease. The systemic impact of hypertension is defined, contrasting common essential hypertension with malignant hypertension, where blood pressure greater than 180 over 120 mmHg causes rapid end-organ damage and papilledema. Structural vessel weakness is examined through various aneurysms, including atherosclerotic abdominal aortic aneurysms, syphilitic aneurysms destroying the vasa vasorum of the ascending aorta, and aortic dissections linked to cystic medial degeneration and severe tearing pain. Venous pathologies are summarized, covering deep vein thrombosis and its critical risk of pulmonary embolism, as well as varicose veins in the lower extremities, esophagus, and anal region. Finally, the chapter categorizes vascular neoplasms, ranging from benign hemangiomas and painful glomus tumors to malignant entities like angiosarcoma and HHV8-associated Kaposi sarcoma found in AIDS patients, providing a complete framework for understanding vascular disease mechanisms.