Flashcards in Anaemia Deck (55):
what are hallmark features of fe deficiency anaemia on a blood film?
red cells are small (microcytic) and pale (hypo chromic), RBCs vary in size and shape
common causes of iron deficiency anaemia?
decreased intake/ increased physiological use of iron, increased loss of iron, malabsorption, blood loss
what is aplastic anaemia?
failure of stem cell growth. Aplastic anaemia is defined as pancytopenia with hypocellularity (aplasia) of the bone marrow; there are no leukaemic, cancerous or other abnormal cells in the peripheral blood or bone marrow. It is usually an acquired condition but may rarely be inherited.
what does a raised RDW value mean on FBE?
variation in size like anistocytosis
what would you think if you saw normoblasts in the peripheral circulation?
you would think extra medullary erythopoeisis or leucoerythoblastic anaemia
what happens to 2,3 BPG in anaemia? how does 2,3 BPG work?
rises, to enhance oxygen offloading. 2,3 BPG stabilises the T configuration of Hb leading to reduced affinity to O2
what are the 4 causes of microcytic anaemia?
Fe deficiency, anaemia of chronic disease, sideroblastic anaemia, thalassemia
what are some causes of macrocytic anaemia?
folate/B12 deficiency (megaloblastic); alcohol, drugs like methotrexate and azathioprine, liver disease, hypothyroidism
what causes normocytic anaemia?
blood loss, chronic renal failure, haemolytic anaemia, anaemia of chronic disease
what are some signs you would look out for on examination for anaemia?
conjunctival pallor, pale palmar creases, dyspnoea, signs of iron deficiency, bone deformities, jaundice
what type of Fe is readily taken up by the body?
Fe2+ (ferrous form)
what are the 3 influences on iron absorption from the gut?
Dietary intake , erythyroid (bone marrow stores) and iron stores
how does hepcidin work?
Hepcidin acts by regulating the activity of the iron exporting protein ferroportin by binding to ferroportin causing its internalization and degradation, thereby decreasing iron efflux from iron exporting tissues into plasma.
Therefore, high levels of hepcidin (occurring in inflammation states) via inflammatory cytokines, e.g. IL-6 will destroy ferroportin and limit iron absorption, and low levels of hepcidin (e.g. in anaemia, low iron stores, hypoxia) will encourage iron absorption
where is iron stored?
skeletal muscle, hepatocytes and reticuloendothelial cells
in what form is iron stored?
ferritin and haemosiderin
what is morphologically characteristic of sideroblastic anaemia?
is sideroblastic anemia acquired or inherited?
both. Can be inherited by X-link or can be acquired by alcohol, myelodysplastic disorders, leukaemia, drugs, lead toxicity
what causes megaloblastic anemia?
defects in DNA synthesis in developing erythrocytes in the bone marrow
what is pernicious anaemia?
Pernicious anaemia (PA) is an autoimmune disorder in which there is atrophic gastritis with loss of parietal cells in the gastric mucosa with consequent failure of intrinsic factor production and vitamin B 12 malabsorption
which type of megaloblastic anaemia would we also expect neuropathy?
B12 deficiency megaloblastic anaemia only
what are some clinical features of marrow failure?
anemia, bleeding and infectionq
what would you see under the microscope of the bone marrow in aplastic anaemia?
A hypocellular or aplastic bone marrow with increased fat spaces
what are some causes of haemolytic anaemia?
Fragmentation e.g. HUS, TTP, DIC; enzyme defects G6P deficiency, Hb deformities e.g. sickle cell and thalassemia; autoimmune warm haemolytic anemia, malaria, drugs like NSAIDs and interferon or inherited haemolytic anaemia
when is a splenectomy indicated?
for inherited haemolytic anaemia like hereditary spherocytosis or thalassemia major
what are the 3 abnormalities which cause haemaglobinopathies?
1. impaired globin chain production
2. impaired global structure
3. combination of the two
how does thalassemia lead to haemolysis?
accumulation of abnormal globin chains in the RBC --> haemolysis
how would we tell the difference between thalassemia and iron deficiency anaemia, as they both appear as microcytic anaemia on blood film?
In thalassemia, serum iron and ferritin are normal.
what do we mean by transfusion haemosiderin?
iron overload as a result of too many blood transfusions
what chains do homozygous beta thalassemia have in the Hb?
Minimal or no beta chains
what is normal type of Hb in adults? What is the normal type of Hb in foetuses?
HbA and HbF respectively
what is HbA2? where do we see this form of Hb?
A2D2 where d= delta chains. See this form of Hb in beta thalassemia
what is HbH and HbBarts? where do we see these forms of Hb?
HbH= 4x beta chains; HbBarts= 4x gamma chains. See these forms of Hb in alpha thalassemia.
what gene mutation causes HbBarts?
4 gene deletion of both alpha and beta chains leading to HbBarts
what is the condition called when babies are born with HbBarts?
what is a known consequence of sickle cell?
what are some causes of acquired haemolytic anaemia
mechanical heart valves, paroxysmal nocturnal haemoglobinuria, systemic disease like liver failure, autoantibodies
what are autoimmune haemolytic anaemias?
Autoimmune haemolytic anaemias are when red cell autoantibodies bind to the red cells, attract complement, and cause them to lyse. Autoimmune haemolytic anaemias can either be classified as warm or cold.
what autoantibodies are generally seen in warm vs cold autoimmune haemolytic anaemias?
Warm- IgG and cold- IgM
what are 5 triggers of autoimmune haemolytic anaemias?
1. Post viral- CMV, EBV
2. lymphomas, leukaemias
3. autoimmune rheumatic conditions like SLE
5. drugs like methlydopa, penicillins, cephalosporins, NSAIDs, interferon, + post transfusions
clinical features of warm autoimmune haemolytic anaemia?
episodes of jaundice and anaemia over period of time, splenomegaly
what do we look for on biochemistry for anaemia of chronic disease?
normal or high ferritin, low iron, low transferrin, low transferrin saturation
what causes anaemia of chronic disease?
Chronic illnesses such as RA/SLE, cancer, HIV, chronic viral hepatitis. Inflammation markers cause increased hepcidin production from liver, increased hemophagocytosis, bone marrow suppression, reduced EPO production leading to anaemia
what sort of biochemistry results would you see for iron deficiency anaemia?
decreased iron, increased transferrin, reduced ferritin
what would you expect the MCV be in haemolytic anaemia?
increased due to compensatory macrocytosis
what kind of inheritance pattern is G6PD deficiency haemolytic anaemia?
x linked recessive
what sort of jaundice is the G6PD deficiency associated with?
what ix would you order for G6PD deficiency?
• Reticulocyte count
• Unconjugated bilirubin
• LDH (low)
• Peripheral blood
• Genetic testing for G6PD
how is G6PD managed?
maintenance folic acid, and if severe anaemia- blood transfusion
what is the normal role of G6PD?
• G6PD is required in the pentose phosphate shunt pathway
• Required to protect RBC from oxidative stress
• Converts NADP to NADPH in response to oxidative stress
- Failure to do this leads to haemolysis
leading worldwide cause of anaemia?
what do pencil cells on a blood film indicate?
iron deficiency anaemia
blood film characteristics of haemolytic anaemia?
oxidative injury (bite cell or blister cells)
what do spherocytes indicate?
or warm haemolytic anaemia
what do we look for microangiopathic haemolytic anaemia
1. Raised LDH
2. Raised reticulocyte count
3. Abnormal blood fim
4. Depressed haptoglobin
5. Unconjugated bilirubin (raised