Nosology is the theory of diseases (from Greek nosos - disease and logos - doctrine) that makes it possible to address a fundamental issue of special pathology and clinical medicine: knowledge of structural and functional relationships in pathology, biological and medical bases of diseases. It comprises issues, without which neither medical theory nor medical practice is possible.
Nosology encompasses the following teachings and concepts:
- etiology, the teaching of the cause of diseases;
- pathogenesis, the teaching of the mechanisms and progression of diseases;
- morphogenesis, the theory of morphological changes that occur during disease development;
- clinical and morphological manifestations of diseases including their complications and outcomes;
- the teaching of the nomenclature and classification of diseases;
- the theory of diagnosis, i.e. identification of diseases;
- pathomorphosis, the theory of disease variability under the influence of various factors;
- medical errors and iatrogenies: diseases or pathological processes caused by the actions of medical personnel.
The way for nosology was paved by D. Morgagni. In 1761, he wrote a 6-volume work “The Seats and Causes of Diseases Investigated by Anatomy”, thereby creating the first scientific classification and nomenclature of diseases. Currently, in accordance with nosology, nosological entities are distinguished. These are specific diseases with a certain etiology and pathogenesis, typical presentations consisting of a combination of characteristic signs and syndromes.
- Sign is a feature of a disease or a pathological condition.
- Syndrome is a totality of symptoms characteristic of a certain disease and associated with shared pathogenesis.
- Disease is a complex term that has no exhaustive wording, however, all definitions emphasize that disease is life. However, in understanding the disease, there are certain provisions of absolute nature.
- The concept of disease necessarily implies a violation of the interaction of the body with the external environment and a change in homeostasis.
- Illness, just like health, is one of the forms of life.
- Illness is a general suffering of the body.
- For a disease to occur, a certain combination of external and internal environmental factors is necessary.
- In the occurrence and course of the disease, compensatory and adaptive reactions of the body play the most important role. They may be sufficient or insufficient for a cure, but it is mandatory that they participate in the course of the disease.
- Any disease causes morphological changes in organs and tissues, which is explained by the unity of structure and function.