Page 255 - Concise Pathology for Exam Preparation ( PDFDrive )

240 SECTION II Diseases of Organ Systems

Pathologic changes
• Variable sized, usually larger than 5–6 cm
• Most frequently fusiform or saccular
• Lumen may contain a mural thrombus
• Two variants of abdominal aortic aneurysms:
• Inflammatory: Less frequent; characterized by dense periaortic fibrosis containing
lymphocytes, plasma cells and macrophages; thought to be due to a localized
immune response to wall of abdominal aorta
• Mycotic: Infected by circulating organisms which cause suppuration
Clinical consequences
• Rupture into peritoneal cavity causing fatal haemorrhage
• Vascular obstruction of a branch of aorta, eg, renal, mesenteric, vertebral leading to
ischaemic injury in the kidney, GIT and spine, respectively
• Embolism from atheroma or mural thrombus
• Compression of ureter or erosion of a vertebra presenting as pain, which is deep, boring,
visceral and felt most prominently in the lumbosacral region
• Presentation as a palpable pulsatile abdominal mass

2. Thoracic aortic aneurysms
Pathogenesis
• Most commonly associated with hypertension
• May also be associated with connective tissue disorders, eg, Marfan syndrome
Pathologic changes
Weakening of the vessel wall leading to progressive dilatation
Clinical consequences
• Breathing difficulty (due to compression of lung and airways)
• Difficulty in swallowing due to compression of oesophagus
• Chronic cough (due to compression of recurrent laryngeal nerve)
• Costovertebral pain (due to erosion of a rib or vertebra)
• Aortic valvular dilation and insufficiency leading to heart failure
• Catastrophic blood loss due to rupture

Q. Define arteriosclerosis.

Ans. The term ‘arteriosclerosis’ is synonymous with ‘hardening of the arteries’ which
indicates reduced elasticity and thickening of arterial walls. Arteriosclerosis has three main
histopathological patterns:
1. Atherosclerosis is the most common and clinically significant pattern of arteriosclero-
sis in which there is formation of intimal fibrofatty plaques.
2. Monckeberg medial calcific sclerosis is an entity in which there are calcific deposits
in muscular arteries of the elderly. These deposits are often visible on imaging but do
not narrow the vessel lumen and therefore have little clinical significance.
3. Hyaline and hyperplastic arteriolosclerosis affect small arteries and arterioles and are
mostly seen associated with hypertension and diabetes mellitus.
Q. Define atherosclerosis. Enumerate the risk factors involved in the
pathogenesis of atherosclerosis.

Ans. Atherosclerosis is characterized by formation of the fibrofatty plaques affecting
primarily the intima of large- and medium-sized muscular arteries (aorta, coronary and
cerebral).

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