What’s Causing That Lymph Node to Swell?
April 14th, 2010 by The Doc
Is it cancer?
This is often the first question that springs to mind whenever someone finds a lump in his or her neck, groin, or armpit. These lumps frequently represent enlarged lymph nodes, which are mistakenly called “glands” by many people.
Lymph nodes are small organs that filter lymph from the various regions of our bodies. Lymph is the fluid that flows between all of our cells and tissues, bathing them with nutrients and vital fluids. Lymph is similar in composition to plasma, which is the liquid component of blood (i.e., what remains when the cells are removed).
Once lymph has circulated through our tissues, most of it returns to the blood vessels, where it mixes with our blood before returning to the heart. A portion of the lymph also enters a separate network of vessels that more or less parallel the blood vessels. At discrete junctions along the course of these lymphatic vessels, lymph nodes act as “sentinels” to capture the lymph, filter it, and analyze it for the presence of infectious organisms, malignant cells, and other unwelcome entities.
White blood cells that reside within the lymph nodes are responsible for mobilizing an immune response to any foreign antigens that might be detected in the lymph. This immune activity usually provokes some degree of inflammation, and inflammation causes the lymph node to swell.
Thus, any stimulus that causes the white cells within a lymph node to react can cause that node to enlarge. Although the proliferation of cancerous cells within a node can certainly cause it to enlarge, cancer is not the most likely reason for lymph node enlargement.
In fact, the potential causes of lymph node enlargement (called lymphadenopathy) are so numerous that even physicians are frequently at a loss to explain why a given node is swollen. When confronted with lymphadenopathy in a patient, many doctors go through a mental checklist to rule out the serious causes and then have the patient return in a few weeks to reevaluate the situation.
Physicians are great fans of mnemonic devices – acronyms that help them to diagnose any number of medical conditions – and this certainly applies to the evaluation of lymphadenopathy.
For example, upon first encountering a patient with an enlarged lymph node (or nodes), most doctors utilize the “ALL AGES” mnemonic: age of the patient; node location; length of time since the node appeared; associated signs and symptoms (fever, weight loss, night sweats, etc.); generalized vs. localized lymphadenopathy; extranodal associations (i.e., are there obvious causes for the nodal enlargement?); is the patient’s spleen enlarged?
This ALL AGES approach helps a doctor to decide whether watchful waiting is appropriate or if a more aggressive evaluation – including, perhaps, biopsy of the lymph node – is merited.
In addition, during their examination of a patient with an enlarged node, physicians use a CHICAGO mnemonic (see below) to guide their thoughts and direct their recommendations for future management. In the overwhelming majority of cases, the ALL AGES and CHICAGO approaches reveal benign causes for the lymphadenopathy.
The CHICAGO mnemonic outlines the plethora of specific conditions that are associated with lymphadenopathy:
Cancers (again, a relatively rare cause of lymphadenopathy): Hodgkin’s disease; non-Hodgkin’s lymphoma; leukemia; multiple myeloma; Waldenström macroglobulinemia; mastocytosis; metastatic breast, prostate, lung, renal, or other tumors
Hypersensitivity (allergy-like) syndromes: drug reactions (Dilantin, indomethacin, gold, allopurinol, carbamazepine, sulfa drugs, etc.); serum sickness; silicone or collagen reaction; vaccination reaction; graft-vs-host disease (found in transplant patients)
Infections: a long list that includes bacteria (staph, strep, cat-scratch fever, tuberculosis, syphilis, etc.); viruses (mononucleosis, hepatitis, cytomegalovirus, colds, herpes, HIV, chickenpox, rubella, etc.); chlamydia; protozoa (toxoplasmosis); rickettsia (scrub typhus, tick fevers, etc.); helminths (subcutaneous or lymphatic worm infestations)
Connective tissue diseases: lupus; dermatomyositis; mixed connective tissue disease; Sjögren’s syndrome, rheumatoid arthritis, etc.
Atypical lymphoproliferative disorders (a term meaning “unusual diseases that cause lymph nodes to get bigger”; it helps to put the “A” in CHICAGO): Castleman disease; angioimmunoblastic lymphadenopathy; lymphomatoid granulomatosis; Wegener’s granulomatosis; etc.
Granulomatosis disorders: tuberculosis and other mycobacterial infections; cat-scratch fever; berylliosis; histoplasmosis; sarcoidosis, etc.
Others: inflammatory pseudotumor of lymph nodes; histiocytic necrotizing lymphadenitis; sinus histiocytosis; vascular disorders, etc.
People who are not physicians may not know all of the fancy terminology, but they can use a similar systematic approach to lymphadenopathy. When confronted with an enlarged lymph node, it helps to remember that lymph drains from our extremities toward our heart, just like our blood does. Thus, if a node in the neck is swollen, it might be reacting to an infection or injury on the scalp, in the ear, or in the throat. Likewise, a swollen node in the groin or armpit might reflect an inflammatory process of the leg or arm, respectively. A careful search of the anatomy “upstream” from an enlarged node often reveals a simple explanation for the node’s behavior; such self-examination can be reassuring…and save the cost and anxiety of an unnecessary doctor visit.
Finally, it always helps to remember that once a lymph node swells in response to an inflammatory stimulus, it can remain swollen for many days, or even weeks. Tender, mobile, spongy nodes are much more likely to be inflammatory (that is, benign) than are nontender, fixed, and firm nodes. The latter merit a doctor’s attention – as does any swollen node that doesn’t resolve within three to four weeks or that continues to enlarge when there’s no apparent reason for it to do so.