In medicine, pathological changes usually refer to the occurrence of pathological phenomena in a part of the body or an organ. For example, people with cardiovascular diseases can be called cardiovascular diseases in medicine. Lesion is a general term, which cannot specifically refer to a certain disease, such as thyroid disease, which can be divided into hypothyroidism, hyperthyroidism, thyroid tumor, etc. Therefore, the commonly used word "disease" in medicine refers to the occurrence of a disease in a certain part or organ, rather than a disease. At the same time, pathological changes can not explain the severity of the disease, such as allergic reactions, which are all immune system diseases.
