Lymphoid Anatomy

Question 1

What are the components of the lymphoid system?

Answer 1

Central (primary) lymphoid tissues:
- bone marrow
- thymus
Peripheral (secondary) lymphoid tissues:
- lymph nodes
- spleen
- tonsils (waldeyer's ring)
- epithelio-lymphoid tissues
- bone marrow

Question 2

What is hypersplenism?

Answer 2

Triad of:

1. splenomegaly
2. fall in one or more cellular components of blood
3. correction of cytopenias by splenectomy

Question 3

What are some causes of splenomegaly?

Answer 3

Infection: e.g. EBV, malaria, TB typhoid, brucellosis, leishmaniasis
Congestion: portal
Haematological disease: lymphoma/leukaemia, haemolytic anaemia, ITP, myeloproliferative disorders
Inflammatory conditions: RA, SLE
Storage diseases: Gaucher’s, Neimann-Pick disease
Miscellaneous: amyloid, tumours, cysts

Question 4

What are the causes of hyposplenism (reduced function of spleen)?

Answer 4

Splenectomy (most common)
Coeliac disease
Sickle cell disease
Sarcoidosis
Iatrogenic

Question 5

What might be seen on a blood film in hposplenism?

Answer 5

Howell-Jolly bodies