How is the cause of swollen lymph nodes diagnosed?
Swollen lymph nodes closer to the surface of the body are generally diagnosed by a doctor's examination and feeling for areas known to have coalescence of lymph nodes, for example, swollen lymph nodes under the arms (axillary lymph nodes), swollen lymph nodes in the sides of the neck (cervical lymph nodes), or swollen lymph nodes in the groin (inguinal lymph nodes). These swollen lymph nodes can be seen and felt easily.
Other times, deeper lymph nodes could be seen on imaging studies, such as CT scan (computed tomography), of different parts of the body.
Tonsils in the back of the throat are also lymph nodes, and they are the most visible ones in the body.
Diagnosing the cause of swollen lymph nodes may be challenging. The most important component of evaluating a swollen lymph node is a thorough medical history and a complete physical examination by a doctor. The doctor may ask about symptoms such as sore throat, fever and chills, fatigue, weight loss, a complete list of medications, sexual activity, vaccination history, recent travels, and the patient's own and his/her family's previous history of cancers if any.
A group of lymph nodes in a particular area of the body reacts to disturbances in that general region. If there is a specific infection in the region of the swollen lymph nodes, that may be the most likely cause of swelling. For instance, infections of the leg or some sexually transmitted diseases can cause swelling of the lymph nodes in the groin area.
Physicians usually examine the lymph nodes by feeling them and characterize them based upon what the lymph nodes feel like. They could be characterized, for example, as:
- Large or small
- Tender or non-tender
- Fixed or mobile
- Hard or soft
- Firm or rubbery
These characteristics can be useful in suggesting the cause of the lymph node swelling. For example, a hard, nontender, non-moveable lymph node may be more characteristic of a cancer spread to that node. On the other hand, a soft, tender, moveable lymph node could more likely represent an infection.
If the enlarged lymph nodes are suspected to be related to a cancer, then a biopsy of the lymph node may determine the cancer type. For example, a swollen lymph node around the collar bone (supraclavicular lymph node), may signify lung cancer in a person who may have other clinical clues suggestive of lung cancer.