Lymphoid organs include the lymph nodes, spleen, liver, thymus, bone marrow, GALT (gut associated lymphoid tissue) and BALT (bronchus associated lymphoid tissue.

Lymphoid diseases include:

Hypoplasia of lymphoid tissue may be due to a congenital or acquired defect

Enlargement of lymph nodes is called lymphadenopathy. Lymphadenopathy may involve a single lymph node, a group of lymph nodes in one anatomic region or may be generalized, involving all lymph nodes. Lymph nodes may be enlarged in response to inflammation or infection of the body part that drains lymph into the lymph node(s) = reactive hyperplasia. For example, the submandibular lymph nodes receive lymph from the oral cavity so a tooth root abcess may result in enlargement of these lymph nodes. Infectious/ inflammatory causes of lymphadenopathy may involve one or many nodes. The following diseases may result in generalized lymphadenopthy:

Fungal infections such as histoplasmosis or blastomycosis

Brucella canis

Systemic lupus erthematosis

Richettsial diseases such as Salmon poisoning or ehrlichia canis

Lymph nodes may be enlarged due to neoplastic processes. Lymphosarcoma most often results in generalized lymphadenopthy, although on occasion a single lymph node may be initially enlarged. Other tumor types may metastasize (spread) to the lymph nodes that receive lymph from the affected anatomic location.

The diagnosis of lymph node diseases:

Lymph nodes can be aspirated or biopsied to obtain information regarding the cause of their enlargement. Additionally specific tests can be performed to evaluate for the presence of select diseases, for example serum tests can be performed to test for exposure to fungal or Richettsial agents. Technique of lymph node aspiration.

This page was last edited on December 15, 2003 by CRD
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