Module 2A - Haematology Flashcards
What are the components of plasma?
- red blood cells
- white blood cells
- platelets
- clotting factors (eg. fibrinogen)
Once clotting factors are removed from blood plasma, what is left is called the serum, what does serum contain?
- Glucose
- Electrolytes –> sodium and potassium
- Proteins –> immunoglobulins (antibodies) and hormones
Thrombopoiesis/erythropoeisis/granulopoiesis/monopoiesis
Blood cells are produced and developed in the bone marrow, this process is called haematopoiesis, draw the lineage starting with a blood stem cell (pluripotent haematopoietic stem cell).
- Thrombopoiesis: megakaryoblasts –> megakaryocytes –> platelets
- Erythropoiesis: erythroblasts –> reticulocytes –> erythrocytes –> RBCs
- Granulopoiesis: granulocytes –> basophils + eosinophils + neutrophils
- Monopoiesis: monocytes –> macrophages + dendritic cells
- B cells –> plasma cells
- NK cells = large granular lymphocyte
What are reticulocytes? and how long do red blood cells survive on average?
- reticulocytes are immature red blood cells
- 120 days (4 months)
B lympocytes (B cells) mature in the ______ ________ and differentiate into; _______ _____ and ________ ______.
T lymphocytes (T cells) mature in the ________ ______ and differentiate into; CD4 cells (T _______ cells), CD_ cells (cytotoxic T cells), and _______ ______ cells
B lymphocytes (B cells) mature in the bone marrow and differentiate into; plasma cells and memory B cells.
T lymphocytes (T cells) mature in the thymus gland and differentiate into; CD4 cells (T helper cells), CD8 cells (cytotoxic T cells), and Natural killer cells.
What are antigens? and name the most relevant antigens in blood transfusions.
- Antigens –> molecules present on the surface of red blood cells (RBCs) that can trigger an immune response if recognized as foreign by the immune system
- ABO system –> Includes A and B antigens. Blood types are A (A antigen), B (B antigen), AB (both A and B antigens), and O (no A or B antigens).
- Rh system –> Includes the D antigen. Blood can be Rh-positive (D antigen present) or Rh-negative (D antigen absent).
What are antibodies? and name the most important antibodies in the context of blood transfusions.
- Antibodies are proteins produced by the immune system that specifically recognize and bind to antigens. In the context of blood transfusions, antibodies can react against foreign blood group antigens.
- Anti-A and Anti-B Antibodies: Present in individuals who lack the corresponding antigens (e.g., a person with blood type A has anti-B antibodies).
- Anti-D Antibodies: Can be produced by Rh-negative individuals if they are exposed to Rh-positive blood.
What is the importance of anti-D in the context of blood transfusions?
- Anti-D is an antibody against the Rh(D) antigen
- Hemolytic Disease of the Newborn (HDN): If an Rh-negative mother is sensitized to Rh-positive blood (e.g., from a previous pregnancy with an Rh-positive baby), she can produce anti-D antibodies that can cross the placenta and destroy the Rh-positive red blood cells of the foetus in subsequent pregnancies.
- Transfusion Reactions: If an Rh-negative person receives Rh-positive blood, they can develop anti-D antibodies, leading to complications in future transfusions.
What is a ‘group and screen’?
A pre-transfusion test.
- Blood Grouping: Determining the ABO and Rh blood type of the patient.
- Antibody Screening: Detecting any unexpected antibodies in the patient’s plasma that could react with transfused blood.
2 types
What is ‘crossmatching’?
- Crossmatching is a compatibility test between the donor’s and recipient’s blood. It involves mixing a small sample of the recipient’s plasma with a sample of the donor’s red blood cells to check for agglutination (clumping) or hemolysis (destruction of red blood cells). There are two types:
- Immediate Spin Crossmatch: A rapid test that detects ABO incompatibility.
- Antiglobulin Crossmatch (Coombs’ test): A more detailed test that detects other antibodies that might cause transfusion reactions.
Describe the ABO blood group system
- AB: universal recipient for ABO system (but can only donate to AB)
- O: universal donor for ABO system (but can only receive from O)
What pre-transfusion (blood transfusion) tests should be done?
- Group and Screen –> Determine ABO and Rh blood type, and screen for unexpected antibodies
- Crossmatch –> Ensure compatibility between donor and recipient blood
What are the 4 blood components that can be given by transfusion?
- Red blood cells
- Platelets
- FFP (Fresh Frozen Plasma)
- Cryoprecipitate
Indications for red blood cell transfusions
- acute blood loss (to restore oxygen-carrying capacity)
- chronic anaemia and symptomatic (Hb levels need to be <70/80g/L)
Indications for platelets transfusions
- thrombocytopenia –> low platelet count
- surgical/procedural prophylaxis –> to prevent bleeding in pts with low platelet counts
- active bleeding –> when platelet count is significantly reduced and patient is actively bleeding or undergoing major surgery
Indications for FFP transfusions
- coagulopathy –> when there is bleeding and abnormal clotting tests (INR >1.5 or APTT >1.5 times normal)
- massive transfusion protocols
- liver disease –> with significant bleeding or before invasive procedures
Indications for cryoprecipitate transfusions
- Fibrinogen deficiency –> cryoprecipitae is rich in clotting factors
- Massive haemorrhage –> as part of massive transfusion protocols to maintain fibrinogen levels
- 71yr old man. pale and tired
- Hb 70g/L (130-170)
- MCV 69fl (83-101)
- Differential diagnosis?
- Next tests?
Findings: microcytic anaemia
Differentials:
- iron-deficiency anaemia
- thalassaemia
- anaemia of chronic disease
- (sideroblastic anaemia, lead poisoning)
Next tests:
- Iron studies –> serum ferritin (low in iron-deficiency anaemia), serum iron (low in iron-deficiency anaemia), Total iron-binding capacity (elevated in iron-deficiency anaemia), transferrin saturation (low in iron-deficiency anaemia)
- Peripheral blood smear
- FIT (faecal immunochemical test) –> checks for blood –> GI bleeding in men with unexplained iorn-deficiency anaemia –> cancer
- reticulocyte count –> assess bone marrow function
- Haemoglobin electrophoresis –> identify thalassaemias
- Inflammatory markers –> CRP/ESR –> anaemia of chronic disease
- 70yr old woman. Pale. Glossitis (inflammation of the tongue)
- Hb 68g/L (120-150)
- MCV 112fl (83-101)
- Differential diagnosis?
- Next tests?
Findings: macrocytic anaemia
Differentials:
- Vit B12 deficiency (often associated with glossitis)
- Folate deficiency
- alcoholism
- livre disease
- hypothyroidism
- myelodysplastic syndromes
- drugs (methotrexate, azathioprine)
Next tests:
- Vit B12 and Folate levels
- Peripheral blood smear
- Reticulocyte count (assess bone marrow response to anaemia)
- Thyroid function tests
- Liver function tests (LFTs)
- serum iron studies (to rule out concurrent iron-deficiency)
- 83yr old woman. Tiredness. PMH (RA, Type 2 DM)
- Hb 85g/L (120-150)
- MCV 89fl (83-101)
- Differential diagnosis?
- Next tests?
Findings: Normocytic anaemia
Differentials:
- anaemia of chronic disease
- acute blood loss
- chronic kidney disease (renal failure)
- Mixed B12/folate and iron deficiency
- bone marrow disorders (aplastic anaemia)
- haemolytic anaemia
Next tests:
- FBC
- Reticulocyte count (low - inadequate production, high - increased destruction or loss of RBCs)
- Iron studies (check for iron-def anaemia)
- Renal function tests
- Inflammatory markets (CRP, ESR)
- Stool occult blood test (check for GI bleeding)
- Bone marrow biopsy
- 63yr old man. Tiredness. Dark urine.
- Hb 85g/L (130-170)
- MCV 105fl (83-101)
- Differential diagnosis?
- Next tests?
Findings: macrocytic anaemia, dark urine suggests possible haemolysis or liver dysfunction
Differentials:
- Haemolytic anaemia
- Vit B12 deficiency
- Folate deficiency
- Liver disease
- alcoholism (liver damage can cause dark urine)
- Myelodysplasia
Next tests:
- FBC
- Peripheral blood smear (haemolysis)
- Reticulocyte count
- Lactate dehydrogenase (LDH)
- Bilirubin (indirect unconjugated, direct conjugated)
- Vit B12 and Folate lvls
- LFTs
- Urinalysis
- Coombs test
- G6PD assay
- Bone marrow biopsy
- 60yr old woman. Hypertension - annual review.
- Hb 120g/L (120-150)
- MCV 65fl (83-101)
- Differential diagnosis?
- Tests?
Findings: microcytic anaemia
Differentials:
- iron-deficiency anaemia
- thalassaemia
- anaemia of chronic disease
- (sideroblastic anaemia, lead poisoning)
Next tests:
- Iron studies: serum ferritin (low in iron-deficiency anaemia), serum iron (low in iron-deficiency anaemia), Total iron-binding capacity (elevated in iron-deficiency anaemia), transferrin saturation (low in iron-deficiency anaemia)
- Peripheral blood smear
- Stool occult blood test: check for GI bleeding)
- reticulocyte count (assess bone marrow function)
- Haemoglobin electrophoresis (identify thalassaemias)
- Inflammatory markers (CRP/ESR - anaemia of chronic disease)
- 26yr old newlywed. Brother has sickle cell disease
- Concerned about risk of child with sickle cell disease
- Normal FBC, no sickle cells on blood film
- Questions?
- What is the risk of having a child with sickle cell disease?
Questions:
- Any hx of sickle cell disease, or any symptoms?
- Family hx of sickle cell?
- Partner’s hx?
- Have you or your partner undergone sickle cell testing, ever had a Hb electrophoresis test?
.
Autosomal recessive:
- risk depends on sickle cell status of both parents
- both have normal Hb: no risk
- one parent has sickle cell trait: 50% risk of inheriting sickle cell trait
- both parents have sickle cell trait: 50% chance sickle cell trait and 25% chance sickle cell disease
- One parent has sickle cell disease: each child will have sickle cell trait, but none will have disease
- one parent has sickle cell disease and other has sickle cell trait: each child has 50% chance of sickle cell disease and 50% chance of sickle cell trait
- 59yr old woman with tiredness and abdominal swelling
- O/E mass in left upper quadrant. Moves on inspiration. Has a notch in it. Can’t get above it
- What is it?
- What might be causing it?
- Questions?
- Tests?
Diagnosis: Splenomegaly
Potential causes:
- Haem disorders (CLL, NHL, myelofibrosis, sickle cell disease)
- Infections (EBV, malaria, TB)
- liver cirrhosis
- Inflammatory disorders (RA, SLE, sarcoidosis)
Questions:
- PMH: hx of haem disorders, infections, autoimmune disorders?
- SH: recent travel (infection risk?), alcohol intake (liver cirrhosis)
- FH: haem disorders, autoimmune disorders
Tests:
- Bloods: FBC, LFTs, blood cultures
- Imaging: abdo ultrasound or CT scan
- bone marrow biopsy (if haem disorders suspected)
- Serology (autoimmune antibodies)