Page 416 - Textbook of Pathology, 6th Edition

400 iv) Small intestine—Ischaemic bowel disease, infarction.
v) Lower extremities—Intermittent claudication, gangrene.

ARTERITIS

Arteritis, angiitis and vasculitis are the common terms used
for inflammatory process in an artery or an arteriole. It may
occur following invasion of the vessel by infectious agents,
or may be induced by non-infectious injuries such as
chemical, mechanical, immunologic and radiation injury. The
non-infectious group is more important than the infectious
type. A classification of arteritis based on this is given in
Table 15.3.

I. INFECTIOUS ARTERITIS

Direct invasion of the artery by infectious agents, especially
bacteria and fungi, causes infectious arteritis. It may be found
in the vicinity of an infected focus like in tuberculosis,
pneumonia, abscesses, etc. or less frequently may arise from
Figure 15.10 Major sites of atherosclerosis (serially numbered) in haematogenous spread of infection such as in infective
descending order of frequency.
endocarditis, septicaemia, etc. Some common types are
described below.
3. Propagation of plaque by formation of thrombi and
emboli. Endarteritis Obliterans
4. Formation of aneurysmal dilatation and eventual rupture. Endarteritis obliterans is not a disease entity but a patho-
Large arteries affected most often are the aorta, renal, logic designation used for non-specific inflammatory
mesenteric and carotids, whereas the medium- and small- response of arteries and arterioles to a variety of irritants. It
sized arteries frequently involved are the coronaries, is commonly seen close to the lesions of peptic ulcers of the
SECTION III
cerebrals and arteries of the lower limbs. Accordingly, the stomach and duodenum, tuberculous and chronic abscesses
symptomatic atherosclerotic disease involves most often the in the lungs, chronic cutaneous ulcers, chronic meningitis,
heart, brain, kidneys, small intestine and lower extremities and in post-partum and post-menopausal uterine arteries.
(Fig. 15.10). The effects pertaining to these organs are
described in relevant chapters later while the major effects Grossly, the affected vessels may appear unaltered
are listed below (Fig. 15.11): externally but on cross-section show obliteration of their
i) Aorta—Aneurysm formation, thrombosis and lumina.
embolisation to other organs. Microscopically, the obliteration of the lumen is due to
ii) Heart—Myocardial infarction, ischaemic heart disease. concentric and symmetric proliferation of cellular fibrous
iii) Brain—Chronic ischaemic brain damage, cerebral tissue in the intima. Though the condition has suffix—itis
infarction.
Systemic Pathology

Figure 15.11 Major forms of symptomatic atherosclerotic disease.