Swollen lymph nodes

Symptoms

Your lymphatic system comprises a network of organs, vessels, and lymph nodes situated throughout your body. Of some 600 lymph nodes, the majority are located in your head and neck region. The lymph nodes that most frequently swell are in this area, as well as in your armpits and groin area.

You may have the following signs and symptoms, depending on the cause of your swollen lymph nodes:

• Enlargement of the affected lymph nodes to 0.4 inches (1 centimeter) or more
• Tender and painful lymph nodes
• Runny nose, sore throat, fever and other indications of an upper respiratory infection
• General swelling of lymph nodes throughout your body — which may indicate an infection, such as HIV or mononucleosis, or immune disorders, such as lupus or rheumatoid arthritis
• Red, inflamed skin over the swollen lymph node
• Swollen limb, possibly indicating lymph system blockage caused by swelling in a lymph node too far under your skin to feel
• Hardened, fixed, rapidly growing nodes, possibly indicating a tumor (rare)

Causes

A lymph node is a small, round or bean-shaped cluster of cells covered by a capsule of connective tissue. The cells are a combination of lymphocytes — which produce protein particles that capture invaders, such as viruses — and macrophages, which break down the captured material. Lymphocytes and macrophages filter your lymphatic fluid as it travels through your body and protect you by destroying invaders.

Lymph nodes occur in groups, and each group drains a specific area of your body. The lymph nodes that most frequently swell are in your neck, under your chin, in your armpits and in your groin. The site of the swollen lymph nodes may help identify the underlying cause.

The most common cause of swollen lymph nodes is an infection, particularly a viral infection, such as the common cold. However, there are other types of infection, including parasitic and bacterial, and other possible swollen lymph node causes. They include:

Common infections

• Strep throat
• Mumps
• Measles
• Ear infections
• Infected (abscessed) tooth
• Mononucleosis
• Wound infections

Other infections

• Tuberculosis
• Certain sexually transmitted diseases, such as syphilis
• Toxoplasmosis — a parasitic infection resulting from contact with the feces of an infected cat or eating undercooked meatCat scratch fever — a bacterial infection from a cat scratch or bite

Immune system disorders

• Lupus — a chronic inflammatory disease that can target your joints, skin, kidneys, blood cells, heart and lungs
• Rheumatoid arthritis — a chronic inflammatory disease that targets the tissue that lines your joints (synovium)
• Human immunodeficiency virus (HIV) — the virus that causes AIDS

Cancers

• Lymphoma — cancer that originates in your lymphatic system
• Leukemia — cancer of your body's blood-forming tissue, including your bone marrow and lymphatic system
• Other cancers that have spread (metastasized ) to lymph nodes

Other possible, but rare causes, include certain medications, such as phenytoin (Dilantin), used to prevent seizures, and certain immunizations, such as for malaria.

Complications

If infection is the cause of your swollen lymph nodes and isn't treated, these complications might occur:

• Abscess formation. An abscess is a localized collection of pus caused by an infection. Pus contains fluid, white blood cells, dead tissue and bacteria or other invaders. An abscess may require drainage and antibiotic treatment. An abscess may cause significant damage if it involves a vital organ.
• Bloodstream infection (bacteremia). A bacterial infection anywhere in your body can progress to sepsis, caused by an overwhelming infection of the bloodstream. Sepsis may result in organ failure and death. Treatment involves hospitalization and intravenous antibiotics.

Diagnosis

Your doctor is likely to take a medical history, ask about when and how your swollen lymph nodes developed, ask about other signs and symptoms, and check your palpable lymph nodes for size, tenderness, warmth and texture. The site of your swollen lymph nodes and your other signs and symptoms will offer clues to the underlying cause.

In addition, your doctor may request laboratory tests to help pin down the diagnosis, including:

• Blood tests. Depending on what your doctor suspects is causing your swollen lymph nodes, he or she may request certain blood tests to confirm or exclude the suspected underlying condition. The specific tests will depend on the suspected cause, but most likely will include a complete blood count (CBC), which helps evaluate your overall health and detect a range of disorders, including infections, such as mononucleosis, and leukemia.
• Imaging studies. A chest X-ray or computerized tomography (CT) scan of the affected area may help determine potential sources of infection or find tumors.
• Lymph node biopsy. If your doctor can't pin down the diagnosis, it may be helpful to remove a sample from a lymph node or even an entire lymph node for microscopic examination. The method of biopsy may be fine-needle aspiration (FNA), which your doctor may perform during an office visit, or he or she may refer you to a surgeon or radiologist for this procedure. In FNA, the doctor inserts a thin, hollow needle into the lymph node and removes (aspirates) cells, which are then sent to a lab for study. Ultrasound — a noninvasive procedure that uses sound waves to create images of organs and tissues — may be used to ensure accuracy. In some cases, you may require an excisional biopsy. This type of biopsy — also called surgical biopsy — removes a portion or all of a lymph node through an incision for analysis. A surgeon performs this procedure while using local or general anesthesia.

References

http://www.mayoclinic.org/diseases-conditions/swollen-lymph-nodes/basics/definition/con-20029652

http://www.nhs.uk/conditions/swollen-glands/Pages/Introduction.aspx

http://www.webmd.com/a-to-z-guides/swollen-lymph-nodes-topic-overview

http://my.clevelandclinic.org/health/diseases_conditions/hic-swollen-lymph-nodes