Lymphadenopathy or adenopathy is a
disease of the
lymph nodes, in which they are abnormal in size or consistency. Lymphadenopathy of an
inflammatory type (the most common type) is lymphadenitis,[1] producing
swollen or enlarged lymph nodes. In clinical practice, the distinction between lymphadenopathy and lymphadenitis is rarely made and the words are usually treated as
synonymous. Inflammation of the
lymphatic vessels is known as
lymphangitis.[2] Infectious lymphadenitis affecting
lymph nodes in the neck is often called
scrofula.
Lymphadenopathy is a common and nonspecific
sign. Common causes include
infections (from minor causes such as the
common cold and post-vaccination swelling to serious ones such as
HIV/AIDS),
autoimmune diseases, and
cancer. Lymphadenopathy is frequently
idiopathic and self-limiting.
Causes
Lymph node enlargement is recognized as a common sign of infectious, autoimmune, or malignant disease. Examples may include:
The most distinctive sign of
bubonic plague is extreme swelling of one or more lymph nodes that bulge out of the skin as "buboes." The buboes often become
necrotic and may even rupture.[5]
Immunocompromised:
AIDS. Generalized lymphadenopathy is an early sign of infection with
human immunodeficiency virus (HIV), the virus that causes acquired immunodeficiency syndrome (AIDS).[20] "Lymphadenopathy syndrome" has been used to describe the first symptomatic stage of
HIV progression, preceding a diagnosis of AIDS.
These
morphological patterns are never pure. Thus, reactive follicular hyperplasia can have a component of paracortical hyperplasia. However, this distinction is important for the
differential diagnosis of the cause.
On
ultrasound,
B-mode imaging depicts lymph node morphology, whilst
power Doppler can assess the vascular pattern.[28] B-mode imaging features that can distinguish
metastasis and
lymphoma include size, shape, calcification, loss of
hilar architecture, as well as intranodal necrosis.[28] Soft tissue edema and nodal matting on B-mode imaging suggests
tuberculous cervical lymphadenitis or previous
radiation therapy.[28] Serial monitoring of nodal size and vascularity are useful in assessing treatment response.[28]
Fine-needle aspiration cytology (FNAC) has
sensitivity and specificity percentages of 81% and 100%, respectively, in the
histopathology of malignant cervical lymphadenopathy.[27]PET-CT has proven to be helpful in identifying occult primary carcinomas of the head and neck, especially when applied as a guiding tool prior to panendoscopy, and may induce treatment related clinical decisions in up to 60% of cases.[27]
Classification
Lymphadenopathy may be classified by:
Size, where lymphadenopathy in adults is often defined as a short axis of one or more lymph nodes is greater than 10mm.[29]
By extent:
Localized lymphadenopathy: due to localized spot of infection; e.g., an infected spot on the scalp will cause lymph nodes in the neck on that same side to swell up
By size, where lymphadenopathy in adults is often defined as a short axis of one or more lymph nodes is greater than 10mm.[29][30] However, there is regional variation as detailed in this table:
Lymphadenopathy of the
axillary lymph nodes can be defined as solid nodes measuring more than 15 mm without fatty hilum.[36] Axillary lymph nodes may be normal up to 30 mm if consisting largely of fat.[36]
In children, a short axis of 8 mm can be used.[37] However, inguinal lymph nodes of up to 15 mm and cervical lymph nodes of up to 20 mm are generally normal in children up to age 8–12.[38]
Lymphadenopathy of more than 1.5–2 cm increases the risk of
cancer or
granulomatous disease as the cause rather than only
inflammation or
infection. Still, an increasing size and persistence over time are more indicative of cancer.[39]
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abPage 559 in: Wolfgang Dähnert (2011). Radiology Review Manual. Lippincott Williams & Wilkins.
ISBN9781609139438.
^Page 942 in: Richard M. Gore, Marc S. Levine (2010). High Yield Imaging Gastrointestinal HIGH YIELD in Radiology. Elsevier Health Sciences.
ISBN9781455711444.