Haematology Week 1 Flashcards
What are the 3 types of blood cells?
Red blood cell
White blood cell
Platlets
What is the production of blood cells called?
Haemopoiesis
What are blood cells made from?
Pluripotent stem cells
What are the sites of haemopoiesis in a foetus?
Yolk sac
3rd - 7th month - spleen
What is the site of haemopoiesis in infants?
Bone marrow - most bones
What is the site of heamopoeisis in adults?
Bone marrow of axial skeleton
What are the 5 types of white blood cells?
Eosinophils Basophils Neutrophils Monocytes Lymphocytes
What do eosinophils look like? What is their function?
BI-lobed nucleus
Red granules
Fight parasitic infection
Involved in hypersensitivity
What is the function of basophils?
Involved in hypersensitivity - release histamine
What do neutrophils look like? What is their function?
Segmented nucleus
Phagocytes, kill with granule contents
What does optical density of RBCs tell you about the concentration?
Optical density is proportional to the concentration
What are the 3 layers of blood after being centrifuged?
Plasma
Buffy coat - WBC
Red blood cells
What is heamatocrit?
Ratio or % of blood that is RBC
What are reticulocytes?
Early red blood cells after denucleification
What doe reticulocytes look like compared to RBCs?
Bigger
No central pallor
If MCV is low what is the problem?
Problem with haemoglobinisation
Is MCV is high what is the problem?
Problem with maturation
What are small RBC with low Hb called?
Microcytic and hypochromic
What are the components of haemoglobin?
Globins
Heam - prophyrin ring and Iron (FE2+)
What are the causes of microcytic anaemia?
Heam deficiency Iron deficiency Porphyrin synthesis problem Congenital sideroblastic anaemia Globin deficiency Thalassaemia
How is iron stored?
In ferritin
What three lab results would confirm a iron deficiency?
Low MCV
Low Haemoglobin
Low serum ferritin
What are 3 causes of iron deficiency?
Lack of iron in diet
Blood loss - GI, menorrhagia
Malabsorption
What transports iron?
Transferrin
Why are macrocytic red cells large?
Because of defects in DNA synthesis and nuclear maturation
Failure to become smaller
What are the 2 main causes of macrocytic anaemia?
B12 Deficiency
Folate deficiency
Where is B12 absorbed?
Ileum
Where is folate absorbed?
Duodenum and jejunum
Name 2 symptoms of macrocytic anaemia?
Weight loss
Diarrhoea
Jaundice
Sore tongue
Name 3 causes of B12 deficiency?
Veganism Pancreatitis Coeliac disease Crowns disease Bowel resection Atrophic gastritis
Name 2 causes of folate deficiency?
Inadequate intake Malabsorption Pregnancy Haemolysis Anti convulsants
What other conditions if pernicious anaemia associated with?
Atrophic gastritis
Hypothyroidism
What auto antibodies may be raised in pernicious anaemia?
Anti gastric parietal cell
Anti intrinsic factor
What is the treatment for pernicious anaemia?
Vitamin B12 injections for life
Name 2 causes of non-megaloblastic macrocytosis?
Alcohol
Liver disease
Hypothyroidism
Marrow failure
Where is erythropoietin released from?
Kidney
Which globins make up metal and adult Hb?
Fetal - alpha and gamma
Adult - alpha and beta
Which chromosome is the alpha gene on?
16
Which chromosome is the beta gene on?
11
What are the 4 classifications of alpha thalassaemia?
Silent alpha trait
Alpha thal trait
HbH disease
Hb barts hydrops fetalis
What happens to the excess beta globin in HbH disease?
Forms beta4 - incapable of carrying oxygen
What mode of inheritance is HbH?
Autosomal recessive
What are the 3 classifications of beta thalassaemia?
Beta thal trait
Beta thal intermedia
Beta thal major
What physical feature might you see in beta thal major and why?
Heptosplenomegaly, skeletal changes - extra medullary heamopoiesis
What mutation causes sickle cell disease?
Point mutation of beta global gene
What type of haemoglobin in seen in sickle cell disease?
HbS - alpha 2 beta s 2
What do HbS become distorted?
When exposed to low O2
What is the main problem with sickled cells?
They cause vessel occlusion and ischaemia
Name 3 causes of sickle cell crisis?
Hypoxia
Dehydration
Cold exposure
Stress, fatigue
When might someone with sickle trait have symptoms?
At altitude under anaesthetic - hypoxia
What long term preventative treatment can be given in sickle cell anaemia?
Education - avoiding triggers Vaccination Prophylactic penicillin Folic acid supplements Hydroxycarbanide
What mode of inheritance is sickle cell anaemia?
Autosomal recessive
What is the function of DMT-1?
Transports iron into duodenal enterocyte
What is the function of ferroportin?
Facilitates iron export from the enterocyte to transferrin
What is the function of hepcidin?
Down regulates ferroportin in response to iron overload - limits iron uptake
What causes iron overload in hereditary haemochromatosis?
Reduced hepcidin synthesis
What is the treatment of hereditary heamochromatosis?
Regulary venesection
What is the treatment of secondary iron overload in patients with anaemia?
Iron chelating agents e.g. desferrioxamine
What is the difference between blood products and blood components?
Blood components are made from 1 or a small number of donors blood
Blood products can be made from 1000’s of donors blood
On which chromosome is blood group gene?
Chromosome 9
Why do people have antibodies to blood that is not their own?
Because bacteria can mimic other blood groups so you make antibodies against these non self antigens
What does the indirect anti globulin or indirect coombs test do?
Tests for irregular antibodies
What 3 things should you do in the case of an immediate haemolytic transfusion reaction?
Stop transfusion, iv fluids, take blood samples
What is the definition of haemolysis?
Premature red cells destruction -shortened red cells survival
What is the difference between compensated and decompensated haemolysis?
Compensated - Hb level maintained
Decompensated - Hb level falls
What is the bone marrow response to haemolysis?
Reticulocystosis
Erythroid hyperplasia
What is extravascular haemolysis?
Destruction of red cells in liver and spleen
What is intravascular haemolysis?
Red cells destroyed in the circulation
What is the difference between products of extravascular and intravascular haemolysis?
Extravascular - normal products in excess
Intravascular - abnormal products - may be life threatening
Name 3 side effects of oral iron supplements?
Constipation, heart burn, black stools
By how much should iron rise per week if patient is compliant with treatment?
10g/l/week
Is anti gastric parietal cell antibody more sensitive or specific?
Sensitive - most patients with pernicious anaemia have it, not everyone with the antibody has anaemia
Is anti intrinsic factor more sensitive or specific?
Specific - if present it is always pernicious anaemia - but it is not always present
What is the pathogenesis of pernicious anaemia?
Autoimmune condition causing destruction of gastric parietal cells - which make intrinsic factor that binds to B12
If patient has low B12 and Folate what must you do and why?
Replace B12 first - otherwise it may cause subacute degeneration of the cord