Persistent generalized lymphadenopathy
Encyclopedia
The lymphatic system
is part of the immune surveillance system. Blood
contains fluid
and blood cell
s. The fluid, which may contain suspended foreign material such as bacteria
and virus
es, seeps through blood vessel
walls into the tissues
, where it bathes the body cells and exchanges substances with them. Some of this lymph fluid is then taken up by lymphatic vessels and passed back to the heart, where it is again mixed with the blood. On its way, the fluid passes through the lymph node
s, small nodular organs located throughout the body but concentrated in certain areas such as the armpits or groin
. These lymph nodes are also known as glands or lymphoid tissue. If they detect something foreign passing through them, they enlarge. This is called lymphadenopathy
or swollen glands. Usually this is localized (for example, an infected spot on the scalp
will cause lymph nodes in the neck on that same side to swell). However, when two or more lymph node groups are involved, it is called generalized lymphadenopathy
. Usually this is in response to a significant systemic disease and will subside once the person has recovered. Sometimes it can persist long-term, even when no explanation for the lymphadenopathy can be found. This is then called persistent generalized lymphadenopathy (PGL).
PGL is often found in cases of autoimmune disease (where the body is attacking itself). These include diseases such as rheumatoid arthritis
, lupus
and sarcoidosis
. Some forms of cancer
will also cause PGL. Sometimes, despite exhaustive investigation, no cause for PGL is found. For the patient and the physician, this can continue to be a source of concern, but many adults have had PGL all their lives and suffered no ill effects. In others, the PGL may persist for a decade or more and then mysteriously subside. Children often have generalized lymphadenopathy of the head and neck, or even PGL, without the finding of a sinister cause. At puberty
this usually disappears.
The immune system
of some people may be sensitized by exposure to a living exogenous irritant such as a bacterial or viral infection, which then results in PGL after the organism has been cleared from the body. In some cases the sensitization is caused by non-living exogenous irritants such as cyclic hydrocarbons (for example, resinous vapours) or pesticide
s and herbicides.
Lymphatic system
The lymphoid system is the part of the immune system comprising a network of conduits called lymphatic vessels that carry a clear fluid called lymph unidirectionally toward the heart. Lymphoid tissue is found in many organs, particularly the lymph nodes, and in the lymphoid follicles associated...
is part of the immune surveillance system. Blood
Blood
Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....
contains fluid
Fluid
In physics, a fluid is a substance that continually deforms under an applied shear stress. Fluids are a subset of the phases of matter and include liquids, gases, plasmas and, to some extent, plastic solids....
and blood cell
Cell (biology)
The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....
s. The fluid, which may contain suspended foreign material such as bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
and virus
Virus
A virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...
es, seeps through blood vessel
Blood vessel
The blood vessels are the part of the circulatory system that transports blood throughout the body. There are three major types of blood vessels: the arteries, which carry the blood away from the heart; the capillaries, which enable the actual exchange of water and chemicals between the blood and...
walls into the tissues
Biological tissue
Tissue is a cellular organizational level intermediate between cells and a complete organism. A tissue is an ensemble of cells, not necessarily identical, but from the same origin, that together carry out a specific function. These are called tissues because of their identical functioning...
, where it bathes the body cells and exchanges substances with them. Some of this lymph fluid is then taken up by lymphatic vessels and passed back to the heart, where it is again mixed with the blood. On its way, the fluid passes through the lymph node
Lymph node
A lymph node is a small ball or an oval-shaped organ of the immune system, distributed widely throughout the body including the armpit and stomach/gut and linked by lymphatic vessels. Lymph nodes are garrisons of B, T, and other immune cells. Lymph nodes are found all through the body, and act as...
s, small nodular organs located throughout the body but concentrated in certain areas such as the armpits or groin
Groin
In human anatomy, the groin areas are the two creases at the junction of the torso with the legs, on either side of the pubic area. This is also known as the medial compartment of the thigh. A pulled groin muscle usually refers to a painful injury sustained by straining the hip adductor muscles...
. These lymph nodes are also known as glands or lymphoid tissue. If they detect something foreign passing through them, they enlarge. This is called lymphadenopathy
Lymphadenopathy
Lymphadenopathy is a term meaning "disease of the lymph nodes." It is, however, almost synonymously used with "swollen/enlarged lymph nodes". It could be due to infection, auto-immune disease, or malignancy....
or swollen glands. Usually this is localized (for example, an infected spot on the scalp
Scalp
The scalp is the anatomical area bordered by the face anteriorly and the neck to the sides and posteriorly.-Layers:It is usually described as having five layers, which can conveniently be remembered as a mnemonic:...
will cause lymph nodes in the neck on that same side to swell). However, when two or more lymph node groups are involved, it is called generalized lymphadenopathy
Generalized lymphadenopathy
Lymph nodes or 'glands' or nodes or lymphoid tissue.are nodular bodies located throughout the body but clustering in certain areas such as the armpit, back of the neck and the groin. They are part of the lymphatic system....
. Usually this is in response to a significant systemic disease and will subside once the person has recovered. Sometimes it can persist long-term, even when no explanation for the lymphadenopathy can be found. This is then called persistent generalized lymphadenopathy (PGL).
PGL is often found in cases of autoimmune disease (where the body is attacking itself). These include diseases such as rheumatoid arthritis
Rheumatoid arthritis
Rheumatoid arthritis is a chronic, systemic inflammatory disorder that may affect many tissues and organs, but principally attacks synovial joints. The process produces an inflammatory response of the synovium secondary to hyperplasia of synovial cells, excess synovial fluid, and the development...
, lupus
Lupus erythematosus
Lupus erythematosus is a category for a collection of diseases with similar underlying problems with immunity . Symptoms of these diseases can affect many different body systems, including joints, skin, kidneys, blood cells, heart, and lungs...
and sarcoidosis
Sarcoidosis
Sarcoidosis , also called sarcoid, Besnier-Boeck disease or Besnier-Boeck-Schaumann disease, is a disease in which abnormal collections of chronic inflammatory cells form as nodules in multiple organs. The cause of sarcoidosis is unknown...
. Some forms of cancer
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
will also cause PGL. Sometimes, despite exhaustive investigation, no cause for PGL is found. For the patient and the physician, this can continue to be a source of concern, but many adults have had PGL all their lives and suffered no ill effects. In others, the PGL may persist for a decade or more and then mysteriously subside. Children often have generalized lymphadenopathy of the head and neck, or even PGL, without the finding of a sinister cause. At puberty
Puberty
Puberty is the process of physical changes by which a child's body matures into an adult body capable of reproduction, as initiated by hormonal signals from the brain to the gonads; the ovaries in a girl, the testes in a boy...
this usually disappears.
The immune system
Immune system
An immune system is a system of biological structures and processes within an organism that protects against disease by identifying and killing pathogens and tumor cells. It detects a wide variety of agents, from viruses to parasitic worms, and needs to distinguish them from the organism's own...
of some people may be sensitized by exposure to a living exogenous irritant such as a bacterial or viral infection, which then results in PGL after the organism has been cleared from the body. In some cases the sensitization is caused by non-living exogenous irritants such as cyclic hydrocarbons (for example, resinous vapours) or pesticide
Pesticide
Pesticides are substances or mixture of substances intended for preventing, destroying, repelling or mitigating any pest.A pesticide may be a chemical unicycle, biological agent , antimicrobial, disinfectant or device used against any pest...
s and herbicides.