5 - Haemopoiesis Flashcards
What are sources of haemopoietic stem cells?
- Aspiration of bone marrow
- Injecting patient with GCSF and collecting by leucopharesis and freezing
- Umbilical cord
What is the reticuloendothelial system?
Part of the immune system and it removes dead or damaged cells and identify and destroys foreign antigens. It contains phagocytic cells
Responsible for removing old RBC’s
Label this cross section of the spleen.
What are some of the functions of the spleen?
- Phagocytosis of old/damaged cells
- Blood pooling
- Extramedullary haemopoiesis
- Immune function with lots of B and T cells stored
When you have a splenectomy what do you have to be aware of?
- Susceptible to infection by encapsulated bacteria
- Increased risk of sepsis
- Therefore given various vaccinations
How is haemoglobin broken down?
Globin = into constituent amino acids
Haem = metabolised to bilirubin and conjugated in the liver and secreted in bile.
Bacteria in colon deconjugate to colourless urobilinogen, which is oxidised to urobilin and stercobilin (making stool brown). some urobilinogen is reabsorbed and processed by kidneys which is why urine is yellow
How do you examine a patient to see if they have splenomegaly?
Never normal to be able to palpate it. Put hand on costal margin and as patient breathes in will feel splenic notch, measure in cm from costal margin in midclavicular line
What can splenomegaly be caused by?
- Back pressure from portal hypertension/cirrhosis
- Overworking red and white pulp in infection or haemolytic anaemia
- Reverting to extramedullary haemopoiesis
- Expansion due to infiltrating cells, e.g cancer cells and metastases
- Infiltration of materials, e.g Gauchers and Sarcoidosis
What are some common infectious diseases that cause splenomegaly?
- EBV
- HIV
- Glandular fever
- Malaria
- Schistosomiasis
What is Gaucher’s disease and sarcoidosis?
Gaucher’s - Defect in beta-glucosidase enxymes that breaks down glucocerebroside (makes up red and white blood cell membranes)
Sarcoidosis - Clumping of inflammatory cells that form objects called granulomas
What can hypersplenism do on blood tests and what precautions should you take with hypersplenism?
- Lowered blood count as more pooling
- Possible rupture so avoid contact sports etc
What are causes of massive, moderate and mild splenomegaly?
Massive - Chronic myeloid leukemia, myelofibrosis, malaria, schistosomiasis
Moderate - Above and lymphoma, leukaemia, myeloproliferative disorders, liver cirrhosis, infections
Mild - Infections like hepatitis, endocarditis, infiltrative disorders like sarcoidosis, autoimmune
What are some issues with ruptured spleens?
- Exsanguiation
- Encapsulated so blood leaks into capsule and causes compression
- Infarction of tissues as blood vessels compressed by splenomegaly
What is hyposplenism?
- Lack of functioning splenic tissue, due to splenectomy, sickle cell disease, coeliac disease
- Patient at risk of overwhelming sepsis due to encapsulated organisms like pneumococcus, haemophilus influenzae and meningococcus
- Hyposplenic prophylaxis
What indicates hyposplenism?
Presence of Howell-Jolly bodies on blood film, small remnants of DNA left when nucleus extruded. Presence of cells means poor splenic function
What type of feedback look is erythropoiesis?
Negative feed back loop, when erythropoietin released, quicker maturation and release of RBC so increase oxyen, stopping erythropoietin release
Why might you get jaundice with a haemolytic disorder?
Large amount of red blood cells being broken down at once, therefore excess bilirubin formation
What is cytopenia and some of the words to describe cytopenia?
Reduction in the number of blood cells
What are the different medical terms used to describe an increase in the number of blood cells.
What is the process of neutrophil maturation?
- Gets bigger, more granules and nucleus folds
What are some causes of neutropenia?
What are some causes of reduced production of neutrophils?
- B12/Folate deficiency
- Malignancy or fibrosis of bone marrow
- Aplastic anaemia
- Radiation as stunned
- Drugs
- Viral infection
- Congenital disorders
What are some consequences of neutropenia?
- Neutropenic sepsis by fungi or bacteria
- Mucosal ulceration
What are some causes of eosinophilia?
What are some causes of basophilia?
What are some causes of lymphocytosis?
