Swollen Lymph Nodes
Swelling of lymph nodes is technically referred to as lymphadenopathy. It is a common symptom that is related to both banal and serious diseases.
Lymph nodes are located in almost all body parts. They have close anatomical relation with local lymphatic vessels. Lymph nodes serve as a kind of defensive guard positions; they are filled with white blood cells that destroy any infectious microorganism or cancer cells located in lymph vessels.
As mentioned above, there are lymph nodes in many parts of our body. However, the doctors are interested mainly in surface areas where swollen lymph nodes can be well diagnosed by physical examination (palpation). These include the neck area (behind the ears, under the lower jaw, near carotid arteries), armpits and supraclavicular areas. Of course, when significantly enlarged, even deep lymph nodes can be palpable (e.g. abdominal lymph nodes) but it is not the rule.
When we investigate swollen lymph nodes, we should be interested in their number location and pain presence. Generally the painful enlargement indicates rather infectious cause, while painless enlargement may be caused by a tumor or an autoimmune disease. Simply said, everyone with long-lasting enlarged lymph nodes (or single lymph node) should seek a doctor, especially when other symptoms are present such as night sweats, recurrent febrile conditions, or unintentional weight loss.
Infection is certainly the most common cause of enlarged lymph nodes. Swelling is caused by proliferation of white blood cells because of contact with infectious microorganisms. Lymphadenopathy can accompany virtually all infections including bacterial, viral, fungal and parasitic. It is typically local (neck lymph nodes in infectious mononucleosis) but in some infections it may be generalized (like HIV infection). Infectious lymphadenopathy has usually painful nodes, but as stated above, it is not the rule.
Virtually any tumor may be associated with swollen lymphatic nodes. Their enlargement is caused by proliferation of tumor cells in the nodes. Classic tumors of organs (e.g. breast cancer, lung cancer, cancers of digestive tract, gynecological tumors, etc.) tend to metastase into local lymph nodes* (near primary tumor lesion) but even distant lymph nodes may be affected. Hematological tumors (“blood cancers”) such as lymphomas and some leukemias (usually ALL and CLL) tend to spread to lymphatic nodes all over the body. Lymph nodes are usually painless and generalized tumors in addition often manifest with night sweats, unintentional weight loss and recurrent fevers.
* From this point of view we talk about so-called sentinel node. It is the node that is the first attacked by local tumor spread. It is usually a lymph node located by a lymphatic vessel that drains the tumor-affected organ. Location of such node is often possible during surgery and its histological examination may serve to evaluation of further prognosis.
Enlarged lymph nodes may be present in any disease caused by autoimmune disorder. Lymfadenopathy can be a diagnostic challenge in this case. As a special pathological unit that belongs among immunopathological diseases, sarcoidosis is very tightly connected to lymphadenopathy.
Medical history and especially physical examination is important. We should evaluate location, size and soreness of enlarged lymph nodes. In medical history we are interested in information of any sign of infection (especially fever), presence of night sweats, weight loss, etc. Blood tests should be performed as blood count can help to diagnose some “blood cancers” and CRP and sedimentation rate may be elevated in infections and autoimmune processes.
Serologically we can diagnose presence of antibodies against various infectious organisms and presence of autoantibodies. If we suspect a hematological disease, further examination may include sternal puncture or trephine biopsy. At least basic imaging methods such as chest X-ray and abdominal ultrasound should be part of examination to exclude enlargement of lymph nodes located deep within abdomen and chest. When cervical lymph nodes are enlarged, it is wise to perform an examination by otolaryngologist.
If the cause of lymph node enlargement is uncertain, the best way of approach is to surgically access and remove one of enlarged nodes and send it for histological examination.