Page 162 - Textbook of Pathology, 6th Edition

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SECTION I

General Pathology and Basic Techniques
Figure 6.16 Sequelae of pyaemia.

neutrophilia; in viral infections lymphocytosis; and in FATE OF ACUTE INFLAMMATION
parasitic infestations, eosinophilia. Typhoid fever, an The acute inflammatory process can culminate in one of the
example of acute inflammation, however, induces leucopenia
with relative lymphocytosis. following outcomes (Fig. 6.17):
1. Resolution. It means complete return to normal tissue
3. Lymphangitis-lymphadenitis is one of the important following acute inflammation. This occurs when tissue
manifestations of localised inflammatory injury. The changes are slight and the cellular changes are reversible e.g.
lymphatics and lymph nodes that drain the inflamed resolution in lobar pneumonia.
tissue show reactive inflammatory changes in the form
of lymphangitis and lymphadenitis. This response 2. Healing. Healing by fibrosis takes place when the tissue
represents either a nonspecific reaction to mediators destruction in acute inflammation is extensive so that there
released from inflamed tissue or is an immunologic is no tissue regeneration. But when tissue loss is superficial,
response to a foreign antigen. The affected lymph nodes it is restored by regeneration.
may show hyperplasia of lymphoid follicles (follicular
hyperplasia) and proliferation of mononuclear phago- 3. Suppuration. When the pyogenic bacteria causing acute
cytic cells in the sinuses of lymph node (sinus histio- inflammation result in severe tissue necrosis, the process
cytosis) (Chapter 14). progresses to suppuration. Initially, there is intense neutro-
philic infiltration. Subsequently, mixture of neutrophils,
4. Shock may occur in severe cases. Massive release of bacteria, fragments of necrotic tissue, cell debris and fibrin
cytokine TNF-α, a mediator of inflammation, in response comprise pus which is contained in a cavity to form an
to severe tissue injury or infection results in profuse abscess. The abscess, if not drained, may get organised by
systemic vasodilatation, increased vascular permeability dense fibrous tissue, and in time, get calcified.
and intravascular volume loss. The net effect of these
changes is hypotension and shock. Systemic activation of 4. Chronic inflammation. Persisting or recurrent acute
coagulation pathway may occur leading to microthrombi inflammation may progress to chronic inflammation in which
throughout the body and result in disseminated the processes of inflammation and healing proceed side by
intravascular coagulation (DIC), bleeding and death. side.