Session 3- Haemopoesis, the Spleen and Bone Marrow

Question 1

what is haemopoiesis

Answer 1

production of blood cells in the bone marrow

bone marrow extensive throughout the skeleton in infant

Question 2

where is bone marrow found in adults

Answer 2

pelvis
sternum
skull
ribs
vertebrae

Question 3

what are HPSC

Answer 3

haemopoietic stem cells
capable of self-renewal
can differentiate into variety of speacilised cells

not normally seen in the blood

Question 4

what is the RES

Answer 4

reticuloendothelial system
part if immune system and made up of monocytes in blood and a network of tissues which contain phagocytic cells ]

role: to remove dead or damaged cells and identify and destroy foreign antigens in blood and tissues

Question 5

main organs of RES

Answer 5

spleen and liver

Question 6

what is the spleen made up of

Answer 6

red pulp- sinuses lined by endothelial macrophages and cords- where RBCs go through

white pulp- similar structure to lymphoid follicles- white cells and plasma preferentially pass through the white pulp

Question 7

function of spleen in adults

Answer 7

sequestration and phagocytosis- old/abnormal red cells removed by macrophages

blood pooling- platelets and red cells can be rapidly mobilised during bleeding

extramedullary haemopoesis- pluripotent stem cells proliferate during haematological stress or if marrow fails

immunological function- 25% of T cells and 15% of B cells are present in spleen

Question 8

how does blood enter the spleen

Answer 8

splenic artery

Question 9

what is splenomegaly

Answer 9

abnormal growth of the spleen

Question 10

what causes splenomagaly

Answer 10

back pressure- portal hypertension in liver disease

over work- red or white pulp

reverting to what it used to do- extramedullary haemopoesis

expanding as infiltrated by cells- cancer cells or metastases

expanding as infiltrated by other material- sarcoidosis - granuloma

Question 11

how do you examine the spleen

Answer 11

it is never normal for the spleen to be palpable below the costal margin

start to palpate in Right Iliac Fossa

feel for spleen edge moving towards your hand on inspiration

feel for splenic notch

measure in cm from costal margin in mid-clavicular line

Question 12

what causes massive splenomegaly

Answer 12

chronic myeloid leukaemia
myelofibrosis
malaria
schistosomiasis

Question 13

moderate splenomegaly

Answer 13

lymphoma 
leukaemia 
myeloproliferative disorders 
liver cirrhosis with portal hypertension 
infections such as Glandular fever 

and everything for massive splenomegaly

Question 14

mild splenomegaly

Answer 14

infectious hepatitis
endocarditis
infiltrative disorders such as sarcodosis
autoimmune diseases

Question 15

hypersplenism

Answer 15

low blood counts can occur due to pooling of blood in enlarged spleen

Question 16

hyposplenism

Answer 16

lack of functioning splenic tissue or no spleen

howell-jolly inclusion bodies- DNA remnants

risk of sepsis from encapsulated bacteria

• streptococcus pneumonia
• haemophilus influenzae
• meningococcus

patients must be immunised and given life long antibiotic prophylaxis

Question 17

causes of hyposplenism

Answer 17

splenonectomy
sickle cells disease
gastrointestinal disease
autoimmune disease

Question 18

degradation of haem

Answer 18

senescent red blood cells engulfed by macrophages in reticuloendothelial system

components broken down

the iron from Haem is recycled

haem converted into unconjugated bilirubin

bilirubin diglucoronide by being conjugated with glucoronic acid then secreted in Bile into duodenum

bilirubin converted to urobilinogen which is subsequently oxidised to sterocobilin which is comes out in faeces

some urobilinogen absorbed into blood and transported to kidney. Oxidised to Urobilin and excreted in urine

Question 19

cytopenia

Answer 19

a reduction in the number of blood cells

Question 20

cytosis or philia

Answer 20

increase in the number of blood cells

Question 21

neutrophilia

Answer 21

increase in absolute number of circulating neutrophils

causes

• infection
• myeloproliferative diseases
• Cytokines- G-CSF
• tissue damage

Question 22

neutropenia

Answer 22

low white cell count 
causes
reduced production 
-B12/ folate deficiency
-aplastic anaemia
-viral infection
-congenital 
-infiltration
-radiation
-drugs 

increased removal or use
-sepsis
-immune destruction
splenic pooling

Question 23

consequences of neutropenia

Answer 23

severe life threatening bacterial infection
severe life threatening fungal infection
mucosal ulceration

Question 24

monocytosis

Answer 24

increase in monocytes

• bacterial infections
• carcinoma
• myeloproliferative disorders and Leukaemia

Question 25

eosinophilia

Answer 25

increase in eosinophilia

common

• allergic diseases
• drug hypersensitivity
• skin diseases
• parasitic infections
• Churg-Strauss

rare

• hodgkin lymphoma
• acute lymphoblastic leukaemia
• acute myeloid leukaemia
• myeloproliferative conditions
• eosinophilic leukaemia
• idiopathic hypereosinophilic syndrome

Question 26

basophilia

Answer 26

reactive

• immediate hypersensitivity reactions
• Ulcerative collitis
• Rheumatoid arthritis

myeloprolifertive

• CML
• MPN
• Systemic mastocytosis

Question 27

lymphocytosis

Answer 27

increase

reactive

• viral infections
• bacterial infections- especially whooping cough
• stress related: MI/ cardiac arrest
• post splenectomy
• smoking

lymphoproliferative- malignant

• chronic lymphocytic leukaemia- B cells
• T or NK cell leukaemia
• lymphoma

Question 28

haemocrit

Answer 28

how much of the blood is RBCs