Pathology

Lecture 27 Diseases of the Blood Vessels

1)To know the broad general categories of ateriosclerosis.

Atherosclerosis

Mönckeberg's arteriosclerosis

Arteriosclerosis

2)To know the typical vessels affected by atherosclerosis.Large and medium-sized muscular arteries (e.g. coronary, carotid) and elastic arteries (e.g. aorta).

3)To be able to characterize the gross and histologic appearance of atheromatous plaques.

Gross: raised, white to yellow plaques on luminal aspect of artery.

Micro: Fibrous plaques contain a central core of cholesterol and cholesterol esters, lipid-laden macrophages or foam cells, calcium and necrotic debris. The core is covered by a subendothelial fibrous cap, made up of smooth muscle cells, foam cells, fibrin and other coagulation proteins, as well as extracellular matrix material, such as collagen, elastin, glycosaminoglycans, and proteoglycans.

4)To be familiar with the general theories of pathogenesis of atherosclerosis.

  1. Endothelial injury/dysfunction - may stimulate SM proliferation, synthesis of collagen, elastic fibers, and proteoglycans; endothelial injury may also induce monocyte migration to the area, with T cell interaction and lipid accumulation.
  2. Smooth muscle proliferation - SM cells synthesize extracellular matrix and accumulated lipids.
  3. Macrophages - accumulated lipids, recruit other WBC's into area, oxidize low-density lipoprotein and stimulate further SM proliferation.
  4. Hyperlipidemia may promote endothelial and smooth muscle cell injury, increases potential penetration of lipids in plaque and formation of lipid-laden foam cells.

5)To know the complications of atherosclerotic plaques and clinical outcomes of atherosclerosis.

Complications: narrowing of the arterial lumen, calcification in ulcer of plaque (thrombi with embolization), hemorrhage into plaque, and weakening of vessel wall with formation of aneurysm.

Clinical Outcomes: MI/ischemic heart disease, cerebral infarct (stroke), gangrene of lower extremities, and intestinal infarction.

6)To be familiar with the risk factors and epidemiology of atherosclerosis.

Risk factors include: advanced age, gender (more common men, but increases in postmenopausal women), genetic predisposition (diabetes, hyperlipidemia, and hypertension), hyperlipidemia particularly hypercholesterolemia, hypertension, cigarette smoking, and diabetes. Less firmly established our obesity, physical inactivity, "Type A" personality with stress factors in lifestyle, hyperuricemia, and use of oral contraceptive drugs (especially with smoking).

Epidemiology: death rate from ischemic heart disease (primarily due to atherosclerosis) is much higher in the US than most other Western countries.

7)To be able to characterize the vessels involved with Mönckeberg’s arteriosclerosis, the types of patients involved, and the microscopic appearance.Vessels in Mönckeberg's arteriosclerosis are medium to small sized arteries, showing calcification of media. It is characterized by ring like calcifications and does not obstruct arterial flow because the intima is not involved Most typically affects the radial and ulnar arteries. Patients are generally older than 50 years (no gender preference). Microscopic: selective calcification of media, no inflammation.

8)To know the main types of arteriosclerosis.

  1. Hyaline arteriosclerosis - characterized by hyaline thickening of arteriolar walls, in the kidney it's termed benign nephrosclerosis it is associated with hypertension.
  2. Hyperplastic arteriosclerosis - characterized by concentric, laminated, "onionskin" thickening of arteriolar walls, in the kidney it's termed malignant nephrosclerosis and is associated with malignant hypertension.

9)For the various types of vasculitis, to be familiar with the following for each major group:

  1. Size of vessels involved.
  2. Organ systems most frequently affected.
  3. Age and gender predilection.
  4. Histologic appearance.
  5. Major clinical presenting signs and symptoms.
  6. Appropriate diagnostic tests.

Type / Size of vessels / Organ systems / Age and gender / Histology / Signs and symptoms / Diagnostic tests
Polyarthritis nodosa (PAN) / Small, medium arteries / Kidney, coronary arteries, musculoskeletal system, GI tract, CNS and PNS / Young adults to middle-age / Fibrinoid necrosis and inflammation of vessel wall / Renal failure, ischemic heart disease, myalgia, arthralgia, arthritis, nausea and vomiting, abdominal pain / Biopsy of affected organ
Hypersensitivity (leukocytoplastic) Angitis / Very small vessels / Skin, lungs, mucous membranes, brain, viscera and muscle. / Neutrophils in vessel wall frequently fragmented producing "nuclear dust" / Palpable purpura, Henoch-Schonlein purpura - arthralgias, hemorrhagic urticaria with fever and GI and renal involvement / Biopsy of the skin
Wegener's Granulomatosis / Small arteries and veins / Respiratory tract, kidneys, and other organs / Middle-aged, males >females / Fibrinoid necrosis, neutrophil infiltration, mononuclear cell infiltration, fibrosis, granuloma formation / Necrotizing granulomatous vasculitis, pulmonary infiltrates, sinusitis, ulceration of nasal mucus membranes, renal abnormalities (hematuria, renal failure) / Nasal/sinus, renal, and bronchial biopsies
Temporal Arteritis / Medium to small arteries / Cranial vessels (especially temporal artery) / Elderly females >males / Granulomatous inflammatory disease / Headache, tenderness over artery, visual disturbances, and facial pain / Erythrocyte sed. rate, temporal artery biopsy

10)To know the major types of aneurysms, their etiologies, characteristic antatomic sites of distribution, presenting clinical complaints and/or clinical outcomes, mechanism of formation, and histologic appearances.

Type / Etiology / Distribution / Clinical Complaints/Outcomes / Mechanism / Histology
Atherosclerotic aneurysms / Atherosclerosis / Abdominal aorta below renal arteries above iliacs / Rupture w/hemorrhage, embolism, compression, occlusion, mass / Vessel dilation / Intimal tear rupture
Syphilitic aneurysms / Inflammatory reaction / Thoracic aorta extending to aortic valve / Symptoms due to compression of adjacent thoracic structures / occlusion of vaso vasorum / Adventitia inflammation, media injury
Dissecting aneurysms / Marfan syndrome / Ascending aorta extends proximally and distally / Chest pain, occlusion of arterial branches of aorta, aortic valve insufficiency, hemorrhage / Dissects through intima / Cystic medial necrosis, medial tear

11)To be responsible for all material covered in the handout on “Diseases of Blood Vessels.”Review handout.