Lymphadenopathy : Causes and initial workup

Lymphadenopathy (LAP) refers to the abnormal enlargement or alteration in the consistency of lymph nodes. Typically, lymph nodes measure up to 1 cm in diameter, though exceptions exist; for instance, inguinal lymph nodes may reach 1.5 cm and epitrochlear nodes about 0.5 cm. In children aged two to ten, lymph nodes are generally more prominent. Lymph nodes exceeding 2 cm can be indicative of malignancies such as lymphoma, or granulomatous diseases like tuberculosis and cat scratch disease.

The etiology of LAP is diverse, ranging from self-limiting infections commonly seen in younger adults to malignancies more prevalent in older populations. Geographic factors also influence etiology; for example, cervical LAP due to tuberculosis is common in certain African regions. Nonspecific reactive changes are the most frequent benign cause of LAP.

Lymph nodes are part of a system that includes blood monocytes, connective tissue macrophages, thymus, spleen, bone marrow, bone, mucosa-associated lymphoid tissue, lymphatic vessels, and interstitial lymphatic fluid.

Role of the Lymphatic System

• Fluid Homeostasis: Returns interstitial fluid to the venous circulation.
• Immune Surveillance: Filters lymph to capture and destroy pathogens, neoplastic cells.
• Lipid Absorption: Transports chylomicrons from the gut via lacteals.

Components of the Lymphatic System

1. Lymph:...