the spleen

Question 1

what are the main three structures of the spleen?

Answer 1

capsule , red pulp and white pulp

Question 2

what does the red pulp consist of ?

Answer 2

consists of venous sinuses and is surrounded by cellular cords , has a role in immunity as it contains macrophages and granulocytes

Question 3

what does the white pulp consist of ?

Answer 3

mainly lymphoid cells , primary follicles and secondary follicles
they have t cells surrounding arterioles (PALS)

Question 4

what type of organ is the spleen ?

Answer 4

reticuloendothelial organ

Question 5

what are the functions of the spleen?

Answer 5

filter function
pooling and storage function
hematopoetic function
role in immunity

Question 6

explain the filter function of the spleen

Answer 6

it has a pitting and a culling function:
the pitting function includes the removal of intra-erythrocytic inclusions from circulating RBCs ( removal of heinz bodies )
the culling function includes the removal of aging or abnormal RBCs

Question 7

explain the pooling and storage function

Answer 7

reticulocytes stay in the spleen for 1-2 days for maturation before release into the circulation

Question 8

what is the role of the spleen in hematopoesis ?

Answer 8

spleen is the main source of RBCs in the 1st 5 months of fetal life

Question 9

where does extra medullary hematopoesis occur?

Answer 9

spleen , liver

Question 10

what is the role of the spleen in immunity ?

Answer 10

when blood circulates through the spleen (white pulp), it causes exposure of antigens to dendritic cells leading to antibody production and cell mediated immune response

Question 11

what type of bacteria do the spleen protect against

Answer 11

encapsulated bacteria

Question 12

immune complications with asplenic patients

Answer 12

more susceptible to infection by encapsulated bacteria

they have delayed IgM or low IgM

Question 13

indications after splenectomy?

Answer 13

patients should be vaccinated to avoid overwhelming post splenectomy infections, should be vaccinated against streptococcus pneumoniae, menegitidits and influenza

Question 14

what are the causes of splenomegaly

Answer 14

reactive causes 
congestive causes 
storage diseases 
systemic diseases 
haematological diseases 
primary splenic tumors 
tropical splenomegaly

Question 15

reactive causes of splenomegaly

Answer 15

inflammations and infections such as bacterial endocarditis, typhoid and infectious mononucleosis oe could be chronic infections such as TB, visceral leishmaniasis

Question 16

congestive causes of splenomegaly

Answer 16

congestive heart failure
portal hypertension
thrombosis of the portal or splenic vein

Question 17

storage diseases causing splenomegaly

Answer 17

gaucher disease ( mainly in children)
Neiman pick disease
histocytosis X

Question 18

systemic diseases causing splenomegaly

Answer 18

sarcoidosis
amyloidosis
collagen diseases

Question 19

haematological cause of splenomegaly

Answer 19

thalassemia major or intermedia
chronic haemolytic anemia
myelofibrosis
marrow infiltration

Question 20

primary splenic tumors

Answer 20

tumors or cysts

Question 21

tropical splenomegaly

Answer 21

due to malaria

Question 22

what are the clinical features of tropical splenomegaly;Malaria

Answer 22

huge splenomegaly
hepatomegaly 
lymphadenopathy 
sever anemia 
moderate thrombocytopenia 
high malaria titre and serum IGM

Question 23

what is hypersplenism ?

Answer 23

an overreactive spleen , this is a clinical syndrome which does not imply a specific mechanism

Question 24

why is there a decrease in one or more of cell lines in hypersplenism ?

Answer 24

due to premature release of cells as a way to get rid of all the pooling causing anemia and cytopenia

Question 25

when can hyposplenism happen?

Answer 25

after a splenectomy
may be due to sickle cell anemia
may be due to splenic artery thrombosis

Question 26

what are the blood findings after splenectomy ?

Answer 26

the white blood cell and platelete counts typically increase

Question 27

what blood findings indicate functional asplenia ?

Answer 27

Howell jolly bodies and target cells

Question 28

what are Howell jolly bodies ?

Answer 28

the Howell body represent the residual of a red cell nucleus that hasn’t been removed by the spleen ,

Question 29

what does the presence of Howell bodies indicate ?

Answer 29

hypo functional spleen or absent spleen