The Spleen, White Cells, Cytopenia

Question 1

What does the spleen consist of?

Answer 1

Red pulp - sinuses lined by endothelial macrophages and cords

White pulp - similar structure to lymphoid follicles

Question 2

How does blood enter the spleen?

Answer 2

Via the splenic artery

Question 3

When blood enters the spleen, what do red cells preferentially pass through?

Answer 3

Red pulp

Question 4

When blood enters the spleen, what do white cells preferentially pass through?

Answer 4

White pulp

Question 5

What are the functions of the spleen in adults?

Answer 5

1) Sequestration and phagocytosis - old/abnormal red cells removed by macrophages
2) Blood pooling - platelets and red cells can be rapidly mobilised during bleeding
3) Extramedullary haemopoiesis
4) Immunological function - 25% of T cells and 15% of B cells present in the spleen

Question 6

Why would the spleen grow?

Answer 6

Overworking red/white pulp
Back pressure - portal hypertension in liver disease
Extramedullary haemopoiesis
Infiltrated by cancer cells
Sarcoidosis

Question 7

What are some causes of hyposplenism?

Answer 7

Splenectomy, sickle cell disease, coeliac disease

Question 8

What does the blood film of a patient with hyposplenism show?

Answer 8

Howell Jolly bodies (DNA remnants) - purple dots

Question 9

What are patients with hyposplenism at risk of?

Answer 9

Overwhelming sepsis, particularly from encapsulated organisms (eg pnemococcus, haemophilus influenzae, meningococcus)

Question 10

What is cytopenia?

Answer 10

Reduction in the number of blood cells

Question 11

What is leucopenia?

Answer 11

Low white cell count

Question 12

What is neutropenia?

Answer 12

Low neutrophil count

Question 13

What is thrombocytopenia?

Answer 13

Low platelet count

Question 14

What is the term for low red cells, white cells and platelets?

Answer 14

Pancytopenia

Question 15

What is the term for a high red cell count?

Answer 15

Erythrocytosis

Question 16

What is the term for a high white cell count?

Answer 16

Leucocytosis

Question 17

What is the term for a high neutrophil count?

Answer 17

Neutrophilia

Question 18

What is the term for a high lymphocyte count?

Answer 18

Lymphocytosis

Question 19

What is the term for a high platelet count?

Answer 19

Thrombocytosis

Question 20

What is the commonest white cell?

Answer 20

Neutrophil

Question 21

What hormone controls the production of neutrophils?

Answer 21

G-CSF

Question 22

What could be used to treat severe neutropenia?

Answer 22

Recombinant G-CSF

Question 23

What defines neutropenia?

Answer 23

<1.5x10^9/L

Severe if <0.5

Question 24

Broadly speaking, what could cause neutropenia?

Answer 24

Reduced production, increased removal or use (eg immune destruction, sepsis, splenic pooling)

Question 25

What things could cause reduced production of neutrophils?

Answer 25

B12/folate deficiency, bone marrow malignancy, aplastic anaemia, radiation, drugs (eg chemotherapy), viral infection, congenital disorders

Question 26

What do lysosomes in monocytes/macrophages contain?

Answer 26

Lysozyme, complement, interleukins, arachidonic acid,

Question 27

What things could cause monocytosis?

Answer 27

Chornic inflammatory conditions, chronic infection, carcinoma, leukaemias

Question 28

What do granules in eosinophils contain?

Answer 28

Arginine, phospholipid, enzymes

Question 29

What could cause eosinophilia?

Answer 29

Allergic diseases, parasitic infection, skin diseases, hodgkin lymphoma, acute lymphoblastic leukaemia, eosinophilic leukaemia etc

Question 30

What are the least common, but largest white cells?

Answer 30

Basophils

Question 31

What are basophils active in?

Answer 31

Allergic reactions and inflammatory conditions

Question 32

What do the granules in basophils contain?

Answer 32

Histamine, heparin, hyaluronic acid, serotonin

Question 33

What things could cause basophilia?

Answer 33

Hypersensitivity, UC, RA, CML, mastocytosis

Question 34

What could cause lymphocytosis?

Answer 34

Viral infections, bacterial infections (especially whooping cough), post splenectomy, smoking, CLL, lymphoma

Question 35

What is aplastic anaemia?

Answer 35

Pancytopenia with hypocellular bone marrow in the absence of an adnormal infiltrate and with no increase in reticulin (fibrosis)