Lymphadinitis Flashcards
Lynph nodes discrete encapsulated structures, are formed of?
-Cortex (made of primary (inactive) and secondary (active) follicles
-Paracortical area (in between and inner to follicles)
-Medulla is towards inside, formed mainly of vascular sinusoids and multiple cells
Cortex, paracortical area, medulla contains what?
Cortex: Lymphoid follicles contain mainly B lymphocytes
Paracortical rea: contain mainly T lymphocytes
medulla: formed mainly of vascular sinusoids and multiple cells (T lymphocytes, plasma cells and macrophages)
Acute Nonspecific Lymphadenitis cause?
Lymph nodes undergo reactive changes by microbiologic agents or foreign matter introduced into wounds
may be isolated or be generalized
Acute Nonspecific Lymphadenitis Grossly is seen as?
nodes become swollen, red, tender, overlying skin is red, abscess may develop
Acute Nonspecific Lymphadenitis microscopically is seen as?
lymphoid follicles have large germinal centers containing numerous mitotic figures To form plasma which produces AB
When the cause is a pyogenic organism, neutrophils are seen around the follicles and within the lymphoid sinuses. the centers of follicles can undergo necrosis
Fate of Acute Nonspecific Lymphadenitis
Either
- revert to normal
- undergo abcess/necrosis/scarring
Chronia Nonspecific Lymphadenitis Depending on the causative agent, can assume one of three patterns, name them!
- Follicular hyperplasia
- Paracortical hyperplasia
- Sinus histiocytosis
Chronia Nonspecific Lymphadenitis grossly?
LN are enlarged, non tender with no signs of acute inflammation
Follicular hyperplasia (Reactive hyperplasia) caused by?
stimuli that activate humoral immunity (antibody response)causing B cell proliferation, which migrate in to follicles creating the follicular reaction
Example for a stimuli that causes follicular hyperplasia?
rheumatoid arthritis, toxoplasmosis
follicular hyperplasia microscopically is seen as?
show multiple, variable sized, large lymphoid follicles which has wide germinal centers surrounded by a collar of small mature B lymphocytes
What is the collar of small mature B lymphocytes
Surrounding the lymphoid follicle called?
Mantle zone
Follicular hyperplasia germinal centre contain?
proliferating B cells tingible body macrophages blue arrow, and a meshwork of antigen-presenting follicular dendritic cells
Paracortical hyperplasia cause?
caused by immune reactions involving the T cell regions of the lymph node.
When activated, parafollicular T cells transform into large proliferating immunoblasts that encroach on the B cell follicles.
Paracortical hyperplasia examples?
In viral infection, vaccinations, drugs
Sinus histocytosis is characterized by?
distention of the lymphatic sinusoids
Sinus histocytosis microscopic picture?
distention of the lymphatic sinusoids, owing to a marked hypertrophy of lining endothelial cells and an infiltrate of macrophages (histiocytes)
Sinus histocytes is often encountered in lymph nodes draining ….?
encountered in lymph nodes draining cancers and may represent an immune response to the tumor or its products
Chronic specific lymphadenitis all types
- TB
- Sarcoidosis
- Syphilis
- Toxoplasmosis
- Brucellosis
Define TB
Chronic infection leads to caseous necrosis (cheese like necrotic tissue)
A granuloma caused by T.B infection is formed of What?
epithelioid macrophages surrounded by a collar of lymphocytes & multinucleated giant cells, undergoes central zone of necrosis (caseous necrosis)
Kikuchi-Fujimoto disease (KFD) etiology?
necrotizing lymphadenitis Of unknown etiology ,prevalent in Asia (Mostly Japan).
KFD clinically show as?
persistently enlarged cervical lymph nodes unresponsive to antibiotic therapy ,predominantly in young females
KFD microscopic pic
The lymph node show an area of necrosis surrounded by collar of lymphocytes, macrophages (histiocytes)
KFD fate
self-limiting disease, resolves spontaneously in several weeks
Cat-Scratch Disease etiology
self-limited lymphadenitis caused by the bacterium Bartonella henselae
Cat-Scratch Disease clinically?
manifests with regional lymphadenopathy, most frequently in the axilla and the neck. The nodal enlargement appears approximately 2 weeks after a cat scratch
Cat-Scratch Disease morph
central necrosis associated with an infiltrate of neutrophils forming irregular stellate necrotizing areas microbe is extracellular and can be visualized with silver stains.
Cat-Scratch Disease fate
lymph node enlargement regresses during a period of 2 to 4 months. Rarely, encephalitis, osteomyelitis develop in patients:
Cat-Scratch Disease diagnosis
based on a history of exposure to cats, the characteristic clinical findings, a positive serologic testing for antibodies to Bartonella, and the distinctive morphologic changes in the lymph nodes.
