Lymphadenopathy

Lymphadenopathy (from Latin lympha — moisture, Greek aden — gland and pathos — disease) is a pathological condition characterized by the enlargement of one or more lymph nodes.

This is one of the most common clinical syndromes in infectious diseases.

Etiology and pathophysiology

Lymph nodes are peripheral organs of the immune system that serve as biological filters. They remove various pathological cells with foreign particles from the lymph. Under normal conditions, lymph nodes are filled with “dormant” T and B lymphocytes.

When a virus or bacterium enters the tissue, it is intercepted by patrolling macrophages, and the tissue fluid with foreign antigens flows to the nearest lymph node. There, antigens are presented to lymphocytes.

A powerful clonal expansion process is initiated: immune cells begin to divide rapidly and continuously to form an army to combat the pathogen. The lymph node enlarges due to active blood flow and local inflammatory edema.

Lymphadenitis is lymphadenopathy accompanied by signs of inflammation (for example, skin redness (erythema), pain in the lymph node).

Clinical significance

Lymphadenopathy is classified into localized (regional) and generalized forms:

• localized (regional) — regional enlargement of lymph nodes indicates the presence of a local infection (for example, submandibular lymph nodes are a classic sign of streptococcal angina or viral pharyngeal infection);
• generalized — lymph nodes are enlarged in two or more independent body areas (neck, axillae, groin), indicating a systemic infection.

Generalized lymphadenopathy is a pathognomonic (specific) symptom for diseases such as HIV infection, cytomegalovirus infection, and Epstein-Barr virus infection (infectious mononucleosis).

In the absence of clear signs of infection, persistent, painless, and dense lymphadenopathy requires a biopsy to exclude oncological hematological diseases (lymphomas).