A localized disease is an
infectious or
neoplastic
A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...
process that originates in and is confined to one
organ system
An organ system is a biological system consisting of a group of organ (biology), organs that work together to perform one or more bodily functions. Each organ has a specialized role in an organism body, and is made up of distinct Tissue (biolog ...
or general area in the body,
[Dorland's Illustrated Medical Dictionary,28th edition. W.B.Saunders, Harcourt Brace & Company] such as a
sprain
A sprain is a soft tissue injury of the ligaments within a joint, often caused by a sudden movement abruptly forcing the joint to exceed its functional range of motion. Ligaments are tough, inelastic fibers made of collagen that connect two or ...
ed ankle, a
boil
A boil, also called a furuncle, is a deep folliculitis, which is an infection of the hair follicle. It is most commonly caused by infection by the bacterium ''Staphylococcus aureus'', resulting in a painful swollen area on the skin caused by ...
on the hand, an
abscess
An abscess is a collection of pus that has built up within the tissue of the body, usually caused by bacterial infection. Signs and symptoms of abscesses include redness, pain, warmth, and swelling. The swelling may feel fluid-filled when pre ...
of finger.
A localized cancer that has not extended beyond the margins of the organ involved can also be described as localized disease, while cancers that extend into other tissues are described as invasive. Tumors that are non-hematologic in origin but extend into the bloodstream or lymphatic system are known as metastatic.
Localized diseases are contrasted with
disseminated diseases and
systemic disease
A systemic disease is one that affects a number of Organ (anatomy), organs and Tissue (biology), tissues, or affects the Human body, body as a whole. It differs from a localized disease, which is a disease affecting only part of the body (e.g., ...
s.
Some diseases are capable of changing from local to disseminated diseases.
Pneumonia
Pneumonia is an Inflammation, inflammatory condition of the lung primarily affecting the small air sacs known as Pulmonary alveolus, alveoli. Symptoms typically include some combination of Cough#Classification, productive or dry cough, ches ...
, for example, is generally confined to one or both
lung
The lungs are the primary Organ (biology), organs of the respiratory system in many animals, including humans. In mammals and most other tetrapods, two lungs are located near the Vertebral column, backbone on either side of the heart. Their ...
s but can become disseminated through
sepsis
Sepsis is a potentially life-threatening condition that arises when the body's response to infection causes injury to its own tissues and organs.
This initial stage of sepsis is followed by suppression of the immune system. Common signs and s ...
, in which the
microorganism
A microorganism, or microbe, is an organism of microscopic scale, microscopic size, which may exist in its unicellular organism, single-celled form or as a Colony (biology)#Microbial colonies, colony of cells. The possible existence of unseen ...
responsible for the pneumonia "seeds" the
bloodstream
In vertebrates, the circulatory system is a system of organs that includes the heart, blood vessels, and blood which is circulated throughout the body. It includes the cardiovascular system, or vascular system, that consists of the heart an ...
or
lymphatic system
The lymphatic system, or lymphoid system, is an organ system in vertebrates that is part of the immune system and complementary to the circulatory system. It consists of a large network of lymphatic vessels, lymph nodes, lymphoid organs, lympha ...
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.
See also
*
Disease
A disease is a particular abnormal condition that adversely affects the structure or function (biology), function of all or part of an organism and is not immediately due to any external injury. Diseases are often known to be medical condi ...
*
Nosology
Nosology () is the branch of medical science that deals with the classification of diseases. Fully classifying a medical condition requires knowing its cause (and that there is only one cause), the effects it has on the body, the symptoms th ...
References
Diseases and disorders
Medical terminology
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