Structure and function of lymph nodes and spleen

Question 1

What are the primary and secondary lymphoid structures?

Answer 1

(1) Primary: Bone marrow and thymus

(2) Secondary: Lymph nodes, spleen, tonsils, adenoids, Peyer’s patches

Question 2

What are the causes of lymphadenopathy?

Answer 2

(1) Inflammation
= Local or systemic (infection, autoimmune)

(2) Malignancy
= Lymphoma, leukaemia, metastatic cancer

Question 3

What is Virchow’s node (Troisier’s sign)?

Answer 3

Enlarged left supraclavicular node, suggests abdominal malignancy (stomach, pancreas)

Question 4

What is a sentinel lymph node and why is it important?

Answer 4

First lymph node to which cancer cells spread

(1) Negative = Tumour is localised

(2) Positive = Further spread, requires more investigation/treatment

Question 5

Where is the spleen located?

Answer 5

Left upper quadrant (LUQ) of the abdomen

Question 6

What are the main clinical features of hyposplenism?

Answer 6

(1) Reduced function → increased infection risk

(2) Causes
= Splenectomy, coeliac disease, sickle cell, sarcoidosis

(3) Howell-Jolly bodies on blood smear

Question 6

What are the key histological components of the spleen?

Answer 6

(1) Red pulp
= Filters blood, contains macrophages

(2) White pulp
= Peri-arteriolar lymphoid sheath, antigen presentation

Question 7

What are the signs of splenomegaly?

Answer 7

(1) LUQ discomfort, fullness after eating, pain (if infarction)

Question 8

What is hypersplenism?

Answer 8

Triad
1. Splenomegaly
2. Cytopenia
3. Correction with splenectomy