Localized disease diseases. Some diseases are capable of changing from local to disseminated diseases. Pneumonia, for example, is generally confined to one or both lungs but can become disseminated through sepsis, in which the microbe responsible for the pneumonia "seeds" the bloodstream or lymphatic system and is transported to distant sites in the body. When that occurs, the process is no longer described as a localized disease, but rather as a disseminated disease. Localized disease A localized disease is an infectious or neoplastic process that originates in and is confined to one organ system or general area in the body, such as
Degenerative disease Degenerative disease Degenerative disease is the result of a continuous process based on degenerative cell changes, affecting tissues or organs, which will increasingly deteriorate over time. In neurodegenerative diseases cells of the central nervous system stop working or die via neurodegeneration. An example of this is Alzheimer's disease. The other two common groups of degenerative diseases are those that affect circulatory system (e.g. coronary artery disease) and neoplastic diseases (e.g. cancers). Many degenerative diseases exist and some are related to aging. Normal bodily wear or lifestyle choices (such as exercise or eating habits) may worsen degenerative diseases, but this depends