What is the significance of an active lymph node?

From the Guidelines

Active lymph nodes should be evaluated and managed based on the underlying cause of their activation, with a focus on assessing the size, consistency, tenderness, and location to determine potential causes and guide treatment decisions. When lymph nodes become active, they typically swell, may become tender to touch, and increase their production of immune cells 1. This activation is a normal immune response as lymph nodes filter lymphatic fluid and trap pathogens, allowing immune cells to encounter and respond to threats. Active lymph nodes commonly occur in the neck, armpits, and groin but can be found throughout the body's lymphatic system.

Key Considerations

• Persistent lymph node activation lasting more than two weeks warrants medical evaluation to rule out serious conditions like infections, autoimmune disorders, or malignancies 1.
• Treatment typically addresses the underlying cause rather than the lymph node itself, with most cases resolving once the triggering infection or inflammation subsides.
• The evaluation of sentinel lymph nodes in breast cancer has shown that detecting nodal metastases is crucial for determining prognosis and guiding treatment decisions 1.
• The size of the metastases, whether macrometastases or micrometastases, can impact the prognosis and treatment approach 1.

Evaluation and Management

• Healthcare providers should assess the size, consistency, tenderness, and location of active lymph nodes to determine potential causes and guide treatment decisions.
• The use of sentinel lymph node biopsy has improved the detection of metastases and has become a crucial tool in the management of breast cancer 1.
• The evaluation of lymph nodes should include thin slicing prior to embedding and the examination of multiple sections to detect all metastases larger than 2.0 mm 1.

From the Research

Definition and Causes of Active Lymph Node

• Active lymph node, also known as lymphadenopathy, refers to abnormalities in the size or consistency of lymph nodes 2.
• A wide range of etiologies contributes to the difficulty in diagnosing lymphadenopathy, from mild self-limited viral infections to grave autoimmune diseases and malignancies 2.
• The most common causes of lymphadenopathy are infections and other non-malignant conditions, but it is essential not to overlook warning signs of a malignant disease to avoid delaying further diagnostics and therapy 3.

Evaluation and Differential Diagnosis

• Detailed history-taking and a thorough physical examination are essential in evaluating lymphadenopathy 2.
• When the cause is unknown, lymphadenopathy should be classified as localized or generalized, and patients with localized lymphadenopathy should be evaluated for etiologies typically associated with the region involved according to lymphatic drainage patterns 4.
• Risk factors for malignancy include age older than 40 years, male sex, white race, supraclavicular location of the nodes, and presence of systemic symptoms such as fever, night sweats, and unexplained weight loss 4.

Specific Types of Lymphadenopathy

• Mediastinal lymphadenopathy is secondary to various benign and malignant etiologies, with malignancy and granulomatous conditions being the most common causes 5.
• Cervical lymphadenopathy is a common problem in children, usually representing a transient response to a benign local or generalized infection 6.
• Acute bilateral cervical lymphadenitis is usually caused by a viral upper respiratory tract infection or streptococcal pharyngitis, while acute unilateral cervical lymphadenitis is caused by streptococcal or staphylococcal infection in 40% to 80% of cases 6.

Management and Treatment

• The treatment of acute bacterial cervical lymphadenitis without a known primary source should provide adequate coverage for both Staphylococcus aureus and Streptococcus pyogenes 6.
• Corticosteroids have limited usefulness in the management of unexplained lymphadenopathy and should not be used without an appropriate diagnosis 2, 4.
• Biopsy options include fine-needle aspiration, core needle biopsy, or open excisional biopsy, depending on clinical presentation, location of the lymphadenopathy, and underlying risk factors 4.