Pathogenesis

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pathogenesis

[¦path·ə′jen·ə·səs]
(medicine)
The origin and course of development of disease.

Pathogenesis

 

the mechanisms by which a disease and its symptoms originate and develop at all levels of the organism— from the level of the molecule to that of organs and bodily systems. In the Soviet Union a special branch of pathology deals with problems of pathogenesis. The development of the study of pathogenesis is an important chapter in the history of medicine.

The major pathogenetic phenomena are injury to cells, tissues, and organs; nonspecific responses of the organism; and standard pathological processes, for example, inflammation. The causes of disease vary, but the range of nonspecific responses is limited; furthermore, the intensity of nonspecific responses and their combination in time vary widely in different patients, even for a single disease. The nonspecific responses that are fairly similar from one patient to the next, for example, fever and intensified production of adrenocortical hormones, were shaped over the course of evolution by exposure to a variety of injurious factors, for example, infection and trauma. The nervous and endocrine systems play an important role in the mechanism of these responses, as was confirmed by many scientists, including I. P. Pavlov, A. D. Speranskii, and H. Selye.

Nonspecific responses and standard pathological processes constitute the subject matter of that subdivision of the branch of pathology that studies general aspects of pathogenesis. The body’s response to a disease is a complex of reactions to injury that, while promoting the survival of the species as a whole, can be either useful or harmful to the individual, depending on such factors as the reactions’ duration and intensity. For example, while a high body temperature generally helps control infection, fevers above 40°C can produce life-threatening consequences, such as a drop in blood pressure.

Nonspecific responses underlie many common symptoms of different diseases. For example, general weakness, sweating, and elevated body temperature are common to influenza, tuberculosis, lymphogranulomatosis, rheumatism, and many other diseases. At the same time, independent diseases, or nosologic entities, and syndromes differ in their underlying pathogenetic mechanisms. These mechanisms are the concern of that subdivision of the branch of pathology that deals with special problems of pathogenesis.

A knowledge of the phenomena of pathogenesis is the basis for diagnosis, prognosis, and specific treatment, that is, treatment aimed at abolishing the main pathological process and pathogenetic factors. Thus, the pathologist must be thoroughly familiar with the typical morphological, biochemical, and physiological changes that take place in tissues, organs, and systems in a given disease and the corresponding clinical symptoms, such as fever and changes in blood composition. For example, a hereditary insufficiency in the production of insulin gives rise to diabetes mellitus in a child; the symptoms disappear after regular administration of insulin. In contrast, causal treatment removes the underlying cause of the disease, while symptomatic treatment relieves or weakens individual symptoms. For example, the causal treatment of purulent meningitis makes use of penicillin; diuretics, which are prescribed to lower dangerously high cerebrospinal fluid pressure, are part of the specific treatment; and pain killers, which are prescribed to relieve headaches and pain in the muscles without affecting the disease itself, are used in the symptomatic treatment. The outcome of a disease may be complete recovery, that is, functional restoration and restoration of the injured tissue. Irreversible changes, on the other hand, may persist after the disease has been cured, for instance, scars can form on an ulcer site.

REFERENCES

See references under , , .

A. I. VOROB’EV, B. B. MOROZ, and A. N. SMIRNOV