Difference between revisions of "Category:Lymph Nodes"

Revision as of 12:36, 4 August 2010

Lymph Nodes

Content

▼ Lymph Nodes
Lymph Nodes - Anatomy & Physiology
Lymph Node in Inflammation
Haemolymph Nodes - Anatomy & Physiology
Lymph Node Abnormalities
Reactive Node Diseases

Category:Lymph Node Responses in Disease

Role of the Lymph Node in Inflammation

Back to Inflammation - Pathology

Diseases Involving Reactive Nodes

Parasitic Diseases

bovine parasitic bronchitis

ostertagiasis

fascioliasis

Bacterial Diseases

clostridial

Diseases Involving Both Reactive Nodes and Lymphadenitis

Tuberculosis - Cattle

viz. brucellosis and Johne's disease

chronicity is caused by persistence of intacellular bacteria in lymph node macrophages
Type IV hypersensitivity, but does not result in visible necrosis as in TB

Johne's disease

Actinobacillosis

Actinomycosis

Equine strangles

acute inflammation
produce pyogenic or necrotic foci in the drainage nodes
involves submaxillary nodes

Streptococcal adenitis or head gland disease

dogs
acute inflammation as in above

Diseases Parasitising the Lymphocytes

organism grows in the lymphocytes and ruptures them
if large infecting dose

- may be rapidly fatal since animal may no tb e able to mount an immunological attack

if smaller infecting dose

- loss of mature lymphocytes causes a dramatic stimulation of the remaining lymphocyte precursors

- node hyperplasia follows

- competition between lymphocytolysis by the organism and lymphocyte production by the nodes

- clinically

- may be swelling of the node at one stage and reduction in size at another

canine distemper

virus

swine fever

virus

bovine east coast fever

protozoan

Leishmaniasis in the dog

Other Lymphadenopathy

Lymph node pigmentation

Lungs

- anthracosis

- carbon derived from soot finds its way to the local nodes in macrophages

Skin

- dermatopathic lymphadenopathy or melanic reticulosis

- in pigmented animals, especially black dogs

- chronic inflammatory skin conditions lead to melanin deposition in hyperplastic nodules

- also occurs in nodes draining skin melanomas where the pigment may be the result of skin ulceration or secondary tumour deposit

- these two should not be confused since the prognosis is very different following surgery

Emphysema

interstitial emphysema

- common in cases of dyspnoea

- more commonly affects bovine lung

- due to well developed pulmonary lobulation and hence much loose interstitial lung tissue

collection of gas bubbles in bronchial and mediastinal lymph nodes

- gas travels to these nodes after gaining entry to the many lymphatic vessels present in the interstitial tissue

Neoplasia

Primary tumours
- Lymphosarcoma (lymphoma)

- of lymphoid cells with lymph node enlargement

- smooth, pale hemogenous but may have areas of necrosis

- may cause pseudo-hyperparathyroidism

Secondary tumours

- nodes often involved in the spread of tumours by extension or metastasis

- usually carcinomas

Haemal Lymph Nodes

ruminants only
small; dark red/brown
develop during foetal life

- lymph node primordia which lose their lymph vessles

- receive all cells and antigen from the BLOOD

functional significance unclear
probably respond to blood-borne antigen

Pages in category "Lymph Nodes"

The following 5 pages are in this category, out of 5 total.

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-==Role of the Lymph Node in Inflammation==
+==Role of the [[Lymph Node in Inflammation]]==
 ''Back to [[Inflammation - Pathology]]
-*  Antigenic material is transported in phagocytes via the tissue lymphatics to the local lymph node.
-* In the subcapsular sinusoids of the lymph node, antigens are exposed to the reticular cell macrophages.
-** These macrophages form a meshwork around the subcapsular, cortical and medullary sinusoids.
-** These reticular cells present the antigen to the appropriate lymphocyte population.
-*** To B-cells in the follicular centres
-*** To T-cells in the parafollicular areas.
-* When stimulated by antigen presentation, the respective areas undergo an increase in size by hperplasia.
-** The lymphocytes produced later leave the lymph node to seek out the source of the antigen in the damaged portion.
-* Bacteria surviving the initial local inflammatory reaction also travel to the lymph node.
-** Travel either in macrophages or as a bacteraemia/septicaemia.
-**  In the lymph node, many bacteria are trapped, degraded and killed, or  exposed to antibody produced by plasma cells in the medullary area.
-** Bacteria set up an acute inflammatory response in the lymph node.
-*** If they are pyogenic, baceria can produce abscessation in the lymph node.
-**** E. g. Strangles.
-***** An upper respiratory tract pathogen in the horse.
-***** Abscesses in the cervical lymph nodes burst to the exterior.
-***** Abscesses in the retropharyngeal node burst into the pharynx
-***** Infection is usually localised to the head and neck, but can spread to cause abscessation elsewhere in the body.
-===Bacteraemia===
-* Bacteria may continue through the lymph nodes and circulate in the blood.
-* These are generally cleared from the blood by other organs containing phagocytes.
-** E.g. the [[Liver - Anatomy & Physiology|liver]], [[Spleen - Anatomy & Physiology|spleen]] and lungs.
-* There are species differences in the ability to remove bacteria.
-** In most species, the majority of clearance is carried out by the [[Liver - Anatomy & Physiology|liver]] and spleen.
-** However, in the pig, the lung removes 60-80% of such bacteria.
-===Septicaemia===
-* Septicaemia is a condition where there are highly pathogenic bacteria circulating and rapidly multiplying in the blood.
-** Accompanied by severe signs of clinical illness due to the liberation of bacterial toxins.
-*** High fever
-*** Rapid respiration
-*** Shock
-** Can result in the death of the animal.
-====Gross Appearance====
-* The lymph nodes, [[Liver - Anatomy & Physiology|liver]] and spleen are very hyperaemic and swollen.
-====Histological Appearance====
-* Capillaries in tissues taken immediately after death show bacteria in their lumens.
 ==Diseases Involving Reactive Nodes==