MEH - Spleen White Cells Cytopenia Flashcards
What is red pulp vs white pulp in the spleen?
Red pulp contains RBC, granulocytes, platelets, plasma - sinuses (engorged with blood) lined by endothelial macrophages and cords (connective tissue)
White pulp - similar structure to lymphoid follicles with especially T and B lymphocytes
What organ does a large spleen put pressure on?
Stomach so have to have small meals
Where do white cells and plasma pass through in the spleen?
Preferentially white pulp
Where do RBC pass through?
Red pulp
What are 4 major roles of the spleen?
Sequestration and phagocytosis of old/damaged RBCs - splenic macrophages
Blood pool - release RBC and platelets during bleeding
Extramedullary haemopoiesis - pluripotent stem cells prolif during haem stress or bone marrow failure e.g. myelfibrosis
Immune function - 25% T cells and 15% B cells present in spleen (more in infection)
What is the broad role of red pulp and white pulp?
Red - RBC sequestration and phagocytosis
White - Immune response - cell mediated and humeral
Is it ever normal to be able to palpate spleen?
No
6 reasons for splenomegaly?
- Back pressure - portal hypertension
- Overworking red pulp e.g. haemolytic anaemia
- Overworking white pulp
- Extramedullary haemopoiesis
- Infiltrated cancer - leukaemia etc
- Infiltrated other - gaucheries disease, sarcoidosis
- Malaria
Via what vessel does blood enter the spleen?
Splenic artery
What would you see typically on a blood film of someone with hyposplenism?
Howell - Jolly bodies
What are Howell - Jolly bodies and why are they present?
Basophilic nucelar remnants (clusters of DNA) in circling erythrocytes. Normally during erythropoiesis erythroblasts expel their nuclei but in some cases a small portion of DNA remains. Such cells would normally be removed by the spleen but presence of these bodies is a good indicator of reduced spleen function
What is leucopenia?
Low WBC count
What is low neutrophil blood count?
Neutropenia
What is pancytopenia?
Low red cells, white cells and platelets
What is leucocytosis?
High WBC count
What is high lymphocyte count?
Lymphocytosis
What is hyposplenism? What are some causes?
Lack of functional spleen
E.g. splenectomy, coeliac, sickle cell
How will Howell Jolly- Bodies look on blood film?
Purple dots
Which are the encapsulated bacteria that hyposplenic patients are particularly at risk of infection from?
Neisseria meningitidis
Haemophilus influenzae
Step pneumoniae
What are some causes of massive splenomegaly (4)?
CML, myelofibrosis, chronic malaria, schistosomiasis
What are some causes of moderate splenomegaly?
As above plus lymphoproliferative disorders, myeloproliferative disorders, liver cirrhosis with portal hypertension, infections such as glandular fever caused by EBV
What are some causes of mild splenomegaly?
Infection hepatitis, endocarditis, infiltrative disorders such as sarcoidosis, autoimmune diseases such as AIHA
How can hypersplenism cause pancytopenia or thrombocytopenia?
Because it can pool blood/platelets so removing it from normal circulation
What is the risk with playing contact sports with splenomegaly?
Risk of rupture if below rib cage
What are some complications of splenomegaly?
Infarction - e.g. sickle cell
Haematoma - can cause anaemia and hypertension in spleen
What is increased lobes on neutrophil indicative of (e.g. 3-5 lobes)?
Vit B12 deficiency
How long do neutrophils live for?
1-4 days
What hormone controls neutrophil maturation/production? What 4 roles does the hormone have?
G-CSF
Increased production of neutrophils
Decreased time to release of mature cells from BM
Enhances chemotaxis
Enhances phagocytosis and killing of pathogens
What are two reasons for immature release of neutrophils e.g. meyeloblast/promyelocyte/myelocyte/metamyelocyte
Haem cancer
Sepsis
What treatment can you give to enhance a patients neutrophils e.g. post chemo neutropenia
Recombinant CSF
What are 10 important causes of neutrophilia
1) Drugs e.g. steroids
2) Acute haemorrhage
3) Myeloproliferative diseases
4) Tissue damage
5) Smoking
6) Infection
7) Cancer
8) Cytokines G-CSF
9) Metabolic/endocrine disorders
10) Acute inflammation
What is the diagnostic level of neutrophils for neutropenia?
<1.5 x 10^9/L
<0.5 is servere
What causes neutropenia?
Decreased production
Increased breakdown or use
What reasons for decreased production of WBC are there?
1) B12/folate deficiency
2) Infiltration by malignancy or fibrosis
3) Aplastic anaemia
4) Radiation
5) Drugs - chemo etc
6) Viral infection - v common
7) Congenital disorders
What are three causes of increased neutrophil removal or use?
Immune destruction
Sepsis
Splenic pooling
What are two others causes of neutropenia?
Benign ethnic neutropenia in afro carribbevn
Cyclic neutropenia
What are 3 complications of neutropenia?
Severe life threatening bacterial infection
Severe life threatening fungal infection
Mucosal ulceration - painful mouth ulcers
What do monocyte lysosomes contain?
Lysozyme, complement, interleukins, arachidonic acid (conditionally essential fatty acid), CSF
What is increased monocytes called?
Monocytosis
When might you see monocytosis (4)?
Chronic inflam conditions - Rheumatoid, SLE, Crohns, Ulcerative colitis
Chronic infection e.g. TB
Carcinoma
Myeloproliferative disorders/leukaemias
How long are eosinophils in circulation? What is their life span
3-5 hours
Lifespan 8-10 days
What do their granules contain?
Arginine
Phospholipid
Enzymes
What can eosinophils phagocytose?
Antigen-antibody complex
When might you see eosinophilia?
Allergic diseases - hay fever, asthma, eczema, aspergillosis
Drug hypersensitivity
Parasitic infections
Hodgkins lymphoma, acute myeloid leukaemia, acute lymphoblastic leukaemia, myeloproliferative conditions, eosinophilic leukaemia, idiopathic hypereosinophilic syndrome
How common are basophils?
Least common
What are they active for?
Allergic reactions and inflammatory conditions
What do their granules contain?
Histamine
Heparin
Hyaluronic acid
Serotonin
When might you see basophilia?
Reactive -
Immediate hypersensitivity reactions
UC
RA
Myeloproliferative disorders
CML etc
When might you see lymphocytosis?
Viral infections Bacterial infections Post splenectomy MI/Cardiac arrest (stress related) Smoking
Lymphoproliferative e.g. CLL (B cells), other lymphomas/leukaemias
What can cause pancytopenia?
Most common is reduced production
Also splenic pooling
How can reduced production of all blood cells occur?
B12 folate deficiency - if advanced Malignancy in bone marrow Marrow fibrosis Idiopathic immune aplastic anaemia Radiation Drugs - chemo Viruses - EBC, viral hepatitis, HIV, CMV Congenital bone marrow failure Fanconi's Anaemia, Dyskeratosis congenita
What non haem malignancy can cause pancytopenia?
Prostate
Breast
Lung
What are symptoms of pancytopenia?
Anaemia symptoms
Thrombocytopenia symptoms (bleeding bruising)
Neutropenia symptoms - fever infection ulcers
Symptoms of underlying cause
What can you do to increase all cells?
GCSF mobilised stem cells from donor - stem cell transplant
