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41 Cards in this Set
- Front
- Back
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When does fetal haemoglobin production start? What precedes it? |
• 4-8 weeks gestations • Hb Gower 1, Hb Gower 2, Hb portland |
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From what type of chains is HbF made? Why is this significant? |
2 alpha and 2 gamma. This gives it a higher affinity for oxygen than maternal haemoglobin allowing gas exchange across the placenta |
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What is the approximate blood volume of a newborn? |
• Term = ~80ml/kg • Preterm = ~100ml/kg |
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What are some causes of anaemia in children? |
Red cell aplasia: • Aplastic anaemia, leukaemia • Paravirus B19 • Diamond-Blackfan • Fanconi anaemia Ineffective erythropoiesis: • IDA, folate deficiency • Chronic inflammation • Chronic renal failure Increased haemolysis: • Red cell membrane disorders (spherocytosis) • Enzyme disorders (Glucose 6 phosphate dehydrogenase deficiency) • Haemoglobinopathies (sickle cell, thalassaemia) • Immune (autoimmune haemolytic anaemia, rh / ABO incompatibility) Blood loss: • Fetomaternal (Vasa previa, placental abruption) • GI (merkels, IBD) • Bleeding disorders (VW, haemophilia) |
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What is the definition of anaemia in: • Neonates • 1-12month olds • 1-12 year olds • Adults |
• <14g/dL • <10g/dL • <11g/dL • <13g/dL (men) and <12g/dL (women) |
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What is Diamond-Blackfan anaemia? What might you expect to see on a peripheral blood film? How is it treated? |
• Congenital hypoplastic anaemia • Normachromic, microcytic anaemia • Oral steroids ± ciclosporin, blood transfusions and bone marrow transplant may be needed |
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What is Fanconi anaemia? What is it's inheritance? What might you expect to see on a peripheral blood film? How is it treated? |
• Inherited bone marrow failure syndrome from impaired DNA repair, transcription, and replication • AR or X linked depending on the gene • Macrocytosis through to pancytopenia (if severe). BOne marrow biopsy shows hypocellular marrow • Bone marrow transplant is only cure, still have increased risk of cancers though |
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What are some sources of dietary iron for children? What are some factors that can decrease absorption of iron? |
• Breast milk (low content but 50% absorbed) • Cow's milk (higher content but only 10% absorbed) • Formula milk • Fortified cereals (only 1-2% absorbed) • Red meat, liver, kidney, oily fish • Pulses, beans, and dark green veg • Dried fruit and nuts • Tannin (in tea) decreases absorption (vitamin C increases), bowel pathologies and anchlorydia can decrease absorption |
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What would you expect to see on peripheral blood film in a patient with IDA? What blood tests might you order and what would you expect the results to be? How long should iron supplementation be continued for? |
• Microcytic, hypochromic anaemia • Serum iron (low), serum ferritin (low), Total iron binding capacity (high) • 3 months after Hb returns to normal range |
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• What might you consider if a patient shows microcytic anaemia that is not responding to iron supplements? What might give you a clue on blood film? |
• Sideroblastic anaemia • Iron ring in RBCs (iron loading in marrow too) |
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What might you expect to see on blood film if someone had a b12 or folate deficiency? |
• Macrocytic, megaloblastic anaemia |
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What are some drugs that can cause folate deficiency anaemia? |
• Methotrexate, sulphonazides, antiepileptics |
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What occurs in hereditary spherocytosis? |
Autosomal dominant condition that caused a mutation in a protein of the RBC membrane. As the mutated protein passes through the spleen it is removed, along with part of the membrane, causing a change in shape from discoid to spherical. This reduces the surface area:volume ratio and makes the RBCs less deformable, congesting in and destroying the micro-vasculature of the spleen |
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How might hereditary spherocytosis present? |
• Jaundice - Severe haemolytic jaundice in first few days of life or intermittent jaundice throughout childhood • Anaemia - May fall furtherer during infections • Splenomegaly • Aplastic crisis (paravirus B19 infection) • Gall stones (raised bilirubin) |
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What is the difference between the direct and the indirect Coomb's test? |
• Indirect is performed antenatally and is to check the blood serum for antibodies • Direct is used to see if any antibodies are bound to the RBCs (in cases of haemolysis) to determine an autoimmune cause |
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What would you suspect if an indirect Coomb's test was weakly positive? Strongly positive? |
• ABO incompatibility • Rhesus incompatibility |
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What is the cause of beta thalassaemia? What is Beta thalassaemia minor/trait? Intermedia? Major? |
• Point mutation of the beta Hb gene on Chr11 causing either a reduction of beta Hb chain production (B+) or no production at all (B-). Beta Hb is one of the globulin chains required to produce HbA. • Carrier state (B/B+), usually asymptomatic (one copy of the reduced production gene, one normal) • One reduced copy, one absent, or both reduced (B+/B-, B+/B+). Can produce small amounts of HbA, HbF production is increased to compensate until about 1 year old. • Both copies are 'no production' (B-/B-). No HbA production at all, presents in 1st year when HbF production stops with severe anaemia and failure to thrive |
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What radiological sign would you look for in Beta thalassaemia? What would you see on blood film? |
• 'Hair on end' on skull xray. Osteopenia may also be present, with frontal bossing due to bone marrow expansion • Target cells and nucleated RBCs |
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What is the treatment for beta thalassaemia major? |
• Regular transufions + iron chelating agens (penicillamine) |
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What is Alpha thalassaemia? What are the different severities? |
• Inherited condition affecting the alpha chains of HbA. Usually there are 4 genes for A-globin (2 on each chr16) - aa/aa • If one out of four is deleted (aa/a-) then the patient is an asymptomatic carrier • If two are deleted (a-/a- or aa/--) then there is may be mild anaemia (microcytosis, ± hypochromic), but is usually still asymptomatic • 3 deletions (a-/--) causes moderate anaemia (HbH disease), jaundice, ulcers, hepatosplenomegaly. May require transfusions • 4 deletions (--/--) death usually occurs in utero unless monthly intrauterine transfusions are performed. Hb Barts is present on electrophoresis (useless). |
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What is the cause of sickle cell anaemia? |
• Single nucleotide polymorphism in the beta-globin gene on chr11. This causes a change in the tertiary structure of the b-globlin, forming HbS instead of HbA. HbS causes bending of the RBCs leading to vasoocculsive events. The sickled RBCs are more fragile also, leading to increased haemolysis. |
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What are the different types of sickle cell disease? |
• Sickle cell anaemia (HbSS) - homozygote for sickle cell gene, virtually all Hb is HbS • HbSC disease - HbC is a different SNP in globlin gene, commonly associated with HbS • Sickle b-thalassaemia (HbSB+)- Inherit one sickle gene and one thalasaemia trait gene • Sickle trait - inherit one sickle gene and one normal gene. Asymptotic unless hypoxic, protected from falciparum malaria |
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What are some common problems associated with sickle cell? |
• Anaemia (chronic or acute / aplastic crisis) • Increased susceptibility to infections • Vaso-occlusive crisis - bone marrow of limbs and spine. AVN of femoral head • Acute chest syndrome (vaso-occlusion) • Sequestration crisis - hepatic or splenic enlargement and infarction • Priapism • Long term: renal dysfunction, heart failure, stroke |
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How is sickle cell managed? |
Chronic: • Hydroxycarbamide (reduces crisis frequency) • Prophylaxs Abx • Bone marrow transplant Acute: • Analgesia • Rehydrate / warm • O2 • ± abx (cephalosporin) if signs of infection • Transfusion |
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Which enzyme is essential for preventing oxidative damage to RBCs? |
Glucose-6-phosphate dehydrogenase |
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What is the inheritance of G6PD deficiency? What would you see on blood film? How is the diagnosis confirmed? |
• X linked • Bite cells, blister cells, and heinz bodies • Measure G6PD activity (not during acute crisis) |
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Which drugs can precipitate haemolysis in G6PD? |
• Abx (quinolones, nitrofurantoin, ciproflaxacin) • Antimalarials • Aspirin • Fava beans |
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What is Henoch-Schönlein Purpura? What is immune thrombocytopenic purpura? |
• Type III hypersensitivity often following URTI • Production of antiplatelet antibodies causing thrombocytopenia and bleeding (epitaxis, purpura, menorrhagia) |
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What is the pathophysiological process of DIC? What would you expect to see on clotting studies investigation? |
• Increased coagulation caused by increased fibrin production as a result of widespread activation of clotting factors (inflammation) • Consumption of clotting factors and platelets • Bleeding due to thrombocytopenia and reduced clotting factors (having been used up in wide spread clotting) • Greatly raised prothrombin time, greatly reduced fibrinogen, greatly raised fibrinogen degradation products |
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What are haemophilia A and B? How are they inherited? How are they treated? |
• A= Deficiency of factor VIII • B= Deficiency of factor IX • X linked recessive • Recombinant factors VIII and IX respectively |
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What are some examples of a coagulopathy? |
• Protein C deficiency • Protein S deficiency • Antithrombin deficiency • Factor V Leiden |
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What are the features of anti-phospholipid syndrome? |
Coagulation Livedo reticularis Obstetric (recurrent haemorrhage) Thrombocytopenia |
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What is Acute Lymphoblastic Leukaemia? What are some details about it? |
• Proliferation of immature blast cells (B or T lymphocytes) leading to bone marrow failure • Most common cancer of childhood • Commonly affects the CNS, liver, spleen, testicles • Philadelphia chromosome +ve in 35% (translocation between 9 and 22 producing an activate tyrosine kinase) |
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What is Acute Myeloblastic Leukaemia? What are some details about it? |
• Malignant proliferation of marrow myeloid elements (myeloid bast cells or stem cells) • Rapidly progressive and aggressive • More common in Down's • Commonest acute leukaemia of adults • Bone marrow shows BLAST CELLS and AUER RODS |
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Which condition can progress into AML? |
Polycythaemia Rubra Vera - Somatice mutation of a single haematopoetic cell (usually erythroid) causing thrombosis, bleeding, and pruritis |
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What is Chronic Myeloid Leukaemia? What are some details about it? |
• Uncontrolled clonal proliferation of myeloid cells • Peak between 40 and 60 • Philadelphia chromosome +ve in 80% • Chronic and insideous • 3 phases - chronic, accelerated, acute |
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What is Chronic Lymphocytic Leukaemia? What are some details about it? |
• Clonal expansion of small lymphocytes (usually B) • Commonest leukaemia, usually >65s • Usually conservative management |
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What can be used to prevent tumour lysis syndrome? |
• Allopurinol |
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What drug is used in the chronic phase of CML and what does it do? |
Imatinib - Activated tyrosine kinase inhibitor |
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What would make you classify a lymphoma as either Hodgkin's or non-Hodgkin's? |
Presence of Reed Sternberg cells - Germinal centre b-cels with 'mirror image nuclei'
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What investigations would you do if you suspected myeloma? What would you see? |
Electorphoresis (serum or urine): • Monoclonal IgG band (2/3rds) or IgA band (1/3rd) • Bence-Jones proteins in the urine • Serum M proteins |
