Page 259 - Concise Pathology for Exam Preparation ( PDFDrive )

244 SECTION II Diseases of Organ Systems

Clinical Features of Atherosclerosis

• Most often and most severely affected are elastic arteries like abdominal aorta, ca-
rotids and iliac; and large- and medium-sized muscular arteries like coronary and
popliteal.
• Symptomatic plaques most often involve arteries supplying the heart, brain, kidneys
and lower extremities.
• Major clinical consequences of atherosclerosis are:
• Myocardial infarction (heart attack)
• Cerebral infarction (stroke)
• Intermittent claudication and peripheral vascular disease (gangrene) of lower
extremities
• Ischaemic bowel disease, infarction and ischaemic strictures of intestine
• Renovascular hypertension

Complications of Atherosclerosis
1. Calcification: Occurs in advanced plaques, especially in aorta and coronaries. The
diseased intima crackles like egg shell when incised.
2. Ulceration: Layers covering the soft pultaceous material of an atheroma may ulcerate
due to trauma or haemodynamic force.
3. Thromboembolization: Thrombosis occurs due to ulceration of the plaque and endo-
thelial damage. Emboli composed of lipid material and debris may arise from the
thrombi.
4. Haemorrhage: Originates either from the luminal blood or rupture of thin capillaries
in adventitia.
5. Aneurysm formation: Severe atherosclerosis causes atrophy and thinning of media
with fragmentation of internal elastic lamina resulting in weakening of vessel wall and
aneurysm formation.
6. Progressive plaque growth: Causes critical stenosis and obstruction of the vessel.

Q. Differentiate between fatty streak and atheroma.
Ans. Differences between fatty streak and atheroma are summarized in Table 10.1.

TABLE 10.1. Differences between fatty streak and atheroma

Features Fatty streak Atheroma
Age affected Starts in children as young as 1 year Affects older individuals
Composition Lipid accumulation is mainly intracellular Large core of extracellular lipid
(lipid filled foam cells); T lymphocytes and
extracellular lipid is present in small amounts
Gross appearance • Multiple yellow, flat lesions less than 1 mm in • Whitish yellow, raised, usually
diameter eccentric lesions, measuring
0.5–1.5 cm in diameter
• Do not encroach upon the lumen • Encroach upon the lumen
Vasculature involved May be distributed in areas other than those Primarily affects elastic as well as
generally affected by atherosclerosis large- and medium-sized muscular
arteries
Geographic May be seen in geographic areas, which have a Common in Western world and
distribution low incidence of atherosclerosis developed countries
Clinical consequences Does not generally cause any obstruction to May cause myocardial and cerebral
blood flow infarction, aortic aneurysms and
peripheral vascular disease

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