Lymph nodes Flashcards

1
Q

What are lymph nodes?

A

Lymph nodes are secondary/peripheral lymphoid structures

They are ovoid, encapsulated collections of lymphoid tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the main primary lymphoid structures?

A

Bone marrow
Thymus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the main secondary lymphoid structures?

A

Lymph nodes
Tonsils
Spleen
Peyer’s patches

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the 2 classes of node group location?

A
  • Superficial
  • Internal
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Lymph drainage of the neck and lower face (Image)

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Lymph drainage of the axilla (Image)

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Lymph drainage of the inguinal region (Image)

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Lymph drainage of the abdominal aorta and pelvic organs (Image)

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What structure surrounds the lymph node?

A

Connective tissue capsule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Describe the movement of lymph through the lymph node

A

Afferent lymphatics ->
Sub-capsular sinus ->
Trabecular sinus ->
Medullary cords and sinuses ->
Hilum ->
Efferent lymphatics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the advantage of cell traffic within lymph nodes?

A

Cell traffic provides interactions for immune responses, allowing antigenic material to interact with fixed lymphoid tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the 3 main regions of the lymph node?

A

Cortex
Paracortex
Medulla

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Describe the structure of the lymph node cortex

A

Nodules of B lymphocytes arranged in follicles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Describe the structure of the lymph node paracortex

A

Mainly contains T lymphocytes, forming inter-follicular tissue which surrounds follicles and extends out and merges with the medulla

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Describe the structure of the lymph node medulla

A

Cords and sinuses draining into hilum
The medulla contains:

  • Blood vessels
  • Sinuses
  • Medullary cords
  • Medullary sinuses
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the 2 classes of follicles within the lymph nodes?

A

Primary
Secondary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Describe the structure and function of pimrary follicles

A

Primary follicles have no germinal centre, and contain small quiescent lymphocytes which are yet to be stimulated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Describe the structure and function of secondary follicles

A

Secondary follicles contain a germinal centre in which B cells form their final form
These are active follicles, reacting to a stimulus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is contained in medullary cords?

A

Plasma cells
B cells
Macrophages

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is contained in medullary sinuses?

A

Histiocytes
Reticular cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What types of cells are present in lymph nodes?

A

Lymphocytes
Macrophages
APCs
Dendritic cells
Endothelial cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are some B cells present in the follicles of lymph nodes?

A
  • Follicle centre cells
  • Mantle cells
  • Marginal cells
  • Plasma cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are some B cells found between follicles in the lymph nodes?

A
  • Post-germinal centre B cells
  • Plasma cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is lymphadenopathy?

A

Lymphadenopathy is lymph node enlargement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What are some descriptions of location of lymphadenopathy?
Localised/Generalised Peripheral/Central
26
What are some causes of lymphadenopathy?
Local inflammation Systemic inflammation Malignancy Genetic or systemic disease
27
What are some possible causes of local inflammation in lymphadenopathy?
- Infection - Vaccination - Dermatopathic
28
What are some forms of infection that have distinct lymphadenopathies patterns?
TB Toxoplasma Cat scratch disease (Bartonella henselae)
29
What are some possible causes of systemic inflammation in lymphadenopathy?
Infection (E.g. viral) Autoimmune/CT disorders
30
What are some possible causes of malignancy in lymphadenopathy?
Lymphoma Leukaemia Metastatic nodal spread
31
What are some genetic or systemic diseases that can lead to lymphadenopathy?
- Sarcoidosis - Kikuchi’s lymphadenitis - Castleman’s disease - IgG4 related disease
32
What is meant by regional lymphadenopathy?
Regional lymphadenopathy is lymph node inflammation found only in one region of the body
33
What presentation may occur in regional, superficial lymph node infection?
Lymphangitis - red lines extending from an inflamed lymph node group
34
What is meant by sentinel node?
This is the first node to which a cancer will metastasise, which can be identified using dye or radioactive isotopes
35
What is meant by generalised lymphadenopathy?
Generalised lymphadenopathy is wide-spread around the body, in a number of locations This suggests a systemic inflammatory, immunological process or widespread malignancy
36
What are the 4 main differentials in lymphadenopathy in order of likelihood?
- Bacterial infection (Regional) - Viral infection (Generalised) - e.g. Glandular fever (EBV) - Metastatic malignancy - Lymphoma
37
What lymph nodes will breast cancer usually metastasise to?
Axillary lymph nodes
38
What lymph nodes will lung cancer usually metastasise to?
Neck and Virchow’s node (Supra-clavicular)
39
How will a lymph node feel in viral infection?
Tender Hard Smooth Non-inflamed Untethered
40
How will a lymph node feel in bacterial infection?
Tender Hard Smooth Inflamed Possibly tethered
41
How will a lymph node feel in lymphoma?
Non-tender Rubbery Smooth Non-inflamed Untethered
42
How will a lymph node feel in metastatic carcinoma?
Non-tender Hard Irregular Un-inflamed Tethered
43
What investigation technique is used in lymphadenopathy if suspicious of malignancy?
Whole lymph node biopsy
44
Why is fine needle aspiration not used in suspicious lymphadenopathy?
This will not provide enough tissue for all samples and for reliable samples
45
What tests can be performed on lymph node biopsy?
- Histology - Immunohistochemistry of tissue (Solid sample) - Immunophenotyping of blood or bone marrow (Liquid sample) - Genetic analysis - Molecular analysis
46
What is an example of a condition that can be diagnosed based on lymph node histology?
Nodular sclerosing Hodgkin's lymphoma
47
What is involved in immunohistochemistry?
Immunohistochemistry involves the staining of a solid lymph node section using antibodies against protein patterns and enzyme reactions CD (Cluster of designation) numbered antibodies are used for varying markers
48
What colour is seen in positive immunohistochemistry?
Brown
49
Name the cell type that responds to CD3
T-cells
50
Name the cell type that responds to CD19 and CD20
B-cells
51
Name the cell type that responds to CD30
Reed-sternberg cells (Hodgkin's lymphoma)
52
Name the cell type that responds to CD23
Follicular dendritic cells
53
What are the 2 forms of genetic analysis used in lymph node biopsy?
G-Banding FISH (Fluorescent In Situ Hybridisation)
54
What does G-banding involve?
G banding involves an aspirate node, grow cells in culture, look at spread of chromosomes
55
What does FISH involve?
FISH (Fluorescent In Situ Hybridisation) involves looking for specific abnormalities in chromosomes using probes that emit specific light colours
56
What is the difference between immunohistochemistry and immunophenotyping?
Immunohistochemistry - Solid tissue Immunophenotyping - Liquid tissue
57
What is involved in molecular analysis?
Molecular analysis involves looking for patterns of gene expression, with multiple analyses looking at patterns of genes that are switched on and off
58
Describe the follicular reaction of lymph node activation
In the follicles, quiescent B cells are activated in response to antigenic challenge Antigen-antibody complexes are captured by follicular dendritic cells (FDCs), which are specialised antigen presenting cells These are mesenchymal and form mesh-works through the germinal centre Antigens on the FDCs are presented to naive B cells T helper cells assist
59
What is the function of follicular dendritic cells?
Follicular dendritic cells, (not dendritic cells) are mesenchymal in origin and provide architectural support to germinal centres They facilitate debris removal through secretion of bridging factor, causing macrophages to come and phagocytose debris They also play a role in antigen capture for memory B cells
60
Describe the dark zone reaction of follicular activation
After the beginning of the follicular reaction, the B cells are triggered to start dividing Clonal expansion occurs in which cells proliferate, differentiate and undergo somatic hypermutation Affinity maturation then occurs, in which B cells with the increased antigen affinity go into the light zone, while the rest apoptose
61
What are the advantages of somatic hypermutation?
Somatic hypermutation is what allows the immune system to adapt quickly to make antibody producing plasma cells and memory B cells This causes up to a million times greater than the normal rate of mutations in the human genome (Some advantageous, some disadvantageous)
62
What are centroblasts?
B cells proliferating in the dark zone (Will become centrocytes in the light zone)
63
Describe the light zone reaction of lymph node activation
In the light zone, positive selection of B cells Cell division slows down and FDCs present antigens to B cells B cells bind and internalise the antigen and present it on their MHCII to T cells This allows T cell to help B cell on its journey
64
What are centrocytes?
Centrocytes are B cells in the light zone, which will become either memory B cells or plasma cells
65
What are the 3 B-cell outcomes of follicular activation?
- Reenter dark zone and keep proliferating (and expressing cMyc to regulate GC formation) - Differentiate into plasma cells - Differentiate into memory B cells
66
What can trigger B-cell response in the lymph node?
Autoimmune conditions Infection IgG4-Related disease
67
What can trigger phagocytic responses in the lymph node?
- Draining a tumour site - Reacting to a tumour - Dermatopathic disease - Granulomatous disease
68
What can trigger a T-cell response in the lymph node?
- Viral infection - Drugs (e.g. phenytoin) - Dermatopathic disease
69
What are some causes of granulomatous lymphadenitis?
- Sarcoidosis (Malignancy may also cause sarcoid) - Mycobacteria (Caseous necrosis) - Granulomatous inflammation