What are lymph nodes and what is their function?
Lymph nodes are small round, bean-shaped organs that are part of the lymphatic system. In turn, the lymphatic system and, therefore, the nodes, are a crucial component in the functioning of our immune system, which protects the body from possible infections and other diseases and their spread.
This lymphatic system is made up of vessels, somewhat larger than capillaries and smaller than veins. The fluid that bathes the cells of our body – interstitial fluid – is collected in part by capillaries and in part by the lymphatic system. This fluid, already as lymph or lymphatic fluid, is slowly transported to the venous system and from there to the heart.
The lymph is made up mainly of water, proteins, minerals and other nutrients and, in turn, by damaged cells or foreign particles such as bacteria or viruses and in cases of cancer , by cancer cells . All lymph passes through the strategically located lymph nodes, where the lymph is cleared of injured cells, cancer cells, and foreign particles.
Lymph nodes contain specialized white blood cells (for example, T and B lymphocytes and macrophages ), designed to engulf and destroy damaged cells, cancer cells, infectious microorganisms, and foreign particles.
Thus, the main functions of the lymphatic system are to remove damaged cells from the body., prevent the spread of an infection (most common) or cancer, in addition to spreading the immune response throughout the rest of the body.
The most nodes are located under the skin at strategic points on the body, especially in -cervicales supraclaviculares- neck, armpits ; others are not accessible. These nodes usually measure from half a centimeter to one centimeter in diameter, although in the groin they can reach two centimeters in normal situation. Sometimes these nodes can be felt under the skin.
What are lymphadenopathy?
An adenopathy or lymphadenopathy is the swelling and enlargement of one or more lymph nodes. In general, swollen nodes, in addition to being palpable, can be painful, spontaneously or on palpation. The lymph nodes become inflamed because, as explained above, their mission is to act as a first-line barrier and retain and destroy infectious microorganisms or damaged or malignant cells that the lymph may contain before returning it to the venous system.
If these cells and infectious microorganisms are very abundant, the lymph node becomes inflamed and, therefore, lymphadenopathy develops. The nodes can become inflamed in a single lymph node chain of the body -localized lymphadenopathy- or in several of them at the same time -generalized lymphadenopathy- If the lymphatic vessels become inflamed, it is called lymphangitis.
In children and adolescents, nodes can sometimes be noticed simply because they are larger and the skin at this age is thinner without indicating adenopathy. In addition, at this age, infections are more frequent and the immune response more intense.
What are the causes of lymphadenopathy?
The most common cause of swollen glands is infection , either by bacteria or by viruses.
Among the main causes of adenopathy are:
- Infection: some of the most common causes are upper respiratory infections such as the flu or cold, which are usually viral in origin; those of the ears, teeth and gums; those that affect the skin near the ganglion such as cellulitis and mononucleosis.
Usually, the lymph nodes that are inflamed are the closest, in this case, those of the neck. An infection from a wound in a limb can also cause adenopathy. In these cases, it is more frequent in the armpit, if it is in the upper limb, or in the groin, if it is in the legs.
Other much less common infections that can cause swollen glands include tuberculosis, toxoplasmosis , cat scratch disease or sexually transmitted diseases (STDs) such as herpes simplex, syphilis or HIV infection. STDs often cause lymphadenopathy in the groin.
- Inflammatory disorder: Immune system disorders such as lupus or rheumatoid arthritis can cause lymphadenopathy. In these cases, lymphadenopathy usually occurs in several areas.
- Cancer: Hodgkin lymphoma, non-Hodgkin lymphoma, leukemia, or other types of tumors that have spread. These are generally generalized lymphadenopathy.
Finally, taking certain medications such as some for malaria prophylaxis, the typhus vaccine, or some anticonvulsants can cause the lymph nodes to swell, although this is a very rare cause.
Sometimes the cause of the inflammation is not known. In these cases we speak of idiopathic adenopathy and it usually disappears on its own.
What are the symptoms of lymphadenopathy?
In addition to the enlargement, swollen glands can cause symptoms such as tenderness and pain, spontaneous or on palpation. When the cause is infectious (the most frequent), the typical symptoms of this infection usually appear: fever, malaise, fatigue. If the cause of adenopathy is an upper respiratory infection, other symptoms such as a runny nose or sore throat may appear.
When adenopathy affects multiple regions of the body, it can be due to infections such as mononucleosis , toxoplasmosis , measles, or HIV. It can also be due to an immune system disorder such as lupus or rheumatoid arthritis. In this case, it may also appear rash skin, joint pain and muscle weakness.
If the nodes are hard, fixed, and growing rapidly, the possibility of cancer or lymphoma should be ruled out .
What is the treatment for swollen glands?
Lymphadenopathy itself does not require specific treatment , but the cause will have to be diagnosed and treated. This swelling of the glands generally indicates that the immune system is working and it is necessary to know why it has started in that way.
The usual thing is that these are self-limited infections that disappear spontaneously (such as a cold) and the nodes return to their normal size when the infection ceases. In any case, it will be the doctor who establishes the basic treatment for the cause or the support treatment for the symptoms such as pain or fever.
The use of antibiotics must be decided by the doctor since it must be ensured that the infection is bacterial or that a superinfection by bacteria superimposed on another pathology has occurred. Only in extreme cases in which the node may suppurate can a surgical drain be used.
If I notice swollen glands, when should I see a doctor?
If the adenopathy is localized, small (less than 2 cm) and coincides with clear symptoms of a disease such as a respiratory tract infection (cough , mucus, fever), the logical thing is to think that this disease is the cause.
When the cold subsides, the adenopathy will. It will be the severity of this infection and not the appearance of adenopathy that should advise us by common sense whether or not to go to the doctor.
If there are no accompanying symptoms of adenopathy and, therefore, there is no apparent cause, or if they appear in several areas of the body, it is necessary to see a doctor.
You should also see a doctor when the adenopathy exceeds two centimeters, if it drains, or if it does not subside within two to three weeks. If the lymphadenopathy is not painful and is accompanied by fever, night sweats or weight loss, you should also see a doctor, especially if there are risk factors for tuberculosis or HIV (immunosuppression or risky sex).
In the case of inguinal adenopathies, if there is no clear and minor cause such as a non-serious injury to the leg, a doctor should be seen to rule out a sexually transmitted disease. This sign may be the first to indicate an STD and early diagnosis and treatment are key.
Is swollen glands a common condition?
Although there is little research on its incidence, lymphadenopathy represents one of the main consultations in Primary Care . According to a study carried out in the Netherlands, once diagnosed – which is achieved in 90% of cases – most turn out to be benign, caused by common infections and stop spontaneously or with the appropriate treatment.