Blood Cell Disorders Flashcards
1
Q
With regard to anaemia
- There is decreased erythropoiesis in haemolytic anaemia.
- Sickle cell anaemia is associated with some protection against malaria
- Neurological complications are often associated with anaemia due to folate deficiency.
- Gene deletions are common in β thalassaemia
- An increase in serum haptoglobin levels is characteristically seen in all cases of intravascular haemolysis.
A
- There is increased erythropoiesis in haemolytic anaemia, to try and recover some destroyed red cells
- Sickle cell anaemia is associated with some protection against malaria
- Neurological complications are often associated with anaemia due to B12 deficiency.
- Gene deletions are common in alpha thalassaemia (beta usually a mutation rather than deletion)
- A decrease in serum haptoglobin levels is characteristically seen in all cases of intravascular haemolysis - this is a hallmark of the process, and is due to the haptoglobin mopping up free
2
Q
regarding β thalassaemia
- it characteristically results from deletion in the β globin gene.
- it may involve an asymptomatic carrier state with no demonstrable REB abnormalities
- it results in marked peripheral haemolysis requiring transfusion in the most severe cases
- it is a major cause of hydrops foetalis and foetal death.
- it may result in iron overload and haemochromatosis
A
it may result in iron overload and haemochromatosis
Poor synthesis of globin -> expansion of bone marrow with poorly functioning erythropoiesis -> excess absorption of iron
- it characteristically results from mutation in the β globin gene.
- Alpha thalassaemia typically has a deletion
-
Alpha thalassaemia may involve an asymptomatic carrier state with no demonstrable REB abnormalities if only one of the 4 copies of gene is affected
- Beta has just 2 copies, and either can have a deletion causing reduced synthesis or no synthesis (thus always abnormal if a mutation is present)
- it results in marked central haemolysis (in the spleen) requiring transfusion in the most severe cases
- Alpha thalassaemia is a major cause of hydrops foetalis and foetal death (?possible with beta, but not a major cause)
3
Q
In anaemia
- Ferritin is usually elevated.
- EPO levels are generally reduced.
- Extramedullary haematopoiesis is important in all age groups
- TIBC can be increased or decreased
- Haemoglobinaemia does not occur
A
TIBC can be increased or decreased
- Ferritin is usually reduced, as it is a storage molecule, and more iron is being used to make extra heme
- EPO levels are generally Elevated (except for renal disease)
- **To try and stimulate more RBC production
- Extramedullary haematopoiesis is important in embryos and foetus
- Haemoglobinaemia does occur in intravascular haemolysis, where it leaks out of broken down RBCs
4
Q
haemolytic anaemia
- complement fixation does not occur during transfusion reaction
- senescent RBC distribution occurs in the vascular system
- serum haptoglobin is elevated in intravascular haemolysis
- serum bilirubin is largely conjugative in severe haemolysis.
- malaria infection can cause haemolytic anaemia
A
malaria infection can cause haemolytic anaemia
- complement fixation does occur during transfusion reaction, as the immune system recognises the foreign cells as foreign
- senescent RBC ?destruction occurs in the vascular system
- senescent means old, and old cells are destroyed
- serum haptoglobin is reduced in intravascular haemolysis, as it is used to mop up excess heme (this is a hallmark of intravascular haemolysis)
- serum bilirubin is largely unconjugated in severe haemolysis.
5
Q
which is not a cause of megaloblastic anaemia
- pregnancy
- folate/B12 deficiency
- EBV infection
- Neoplasm
- Hyperthyroidism
A
EBV infection
6
Q
Features of iron deficiency
- Increased serum ferritin
- Decreased transferrin saturation
- Decreased TIBC
A
Decreased transferrin saturation
- Ferritin is reduced, and TIBC is increased.*
- TIBC is an indirect measure of transferrin, a protein to transport iron.*
- TIBC measures the ability of the body to carry iron, so in iron deficiency it is increased as the body attempts to maximise what little iron it has.*
7
Q
Sickle cell anaemia
- Is a thalassaemia
- In the heterozygote does not cause sickling
- Is caused by reduced G6PD
- Causes normoblastic hyperplasia of bone marrow
- Gives resistance against haemophilis influenzae
A
Causes normoblastic hyperplasia of bone marrow
- Is not a thalassaemia - thalassaemia is a reduction in alpha or beta globin synthesis, sickle cell is a mutation with hemoglobin itself
- In the heterozygote does cause sickling, but only under conditions of profound hypoxia
- Homozygotes sickle much more easily
- Is caused by mutations on the beta-globin gene
- Gives resistance against Malaria
8
Q
iron deficiency anaemia features
- a normal haematocrit
- increased serum ferritin
- normal mean cell volume
- low platelet count
- none of the above
A
none of the above
- a reduced haematocrit
- reduced serum ferritin
- reduced mean cell volume
- normal platelet count
9
Q
With regards to anaemia, which is true
- In most anaemias there is a reduction in erythropoiesis
- Haemolytic anaemias are associated with decreased reticulocyte count.
- In pernicious anaemia there is hypertrophy of gastric parietal cells.
- With intravascular haemolysis there is a reduction in serum haptoglobins
- Lymphoma is not associated with cold agglutinins
A
With intravascular haemolysis there is a reduction in serum haptoglobins
Hallmark of the disease - haptoglobins mop up the free haemoglobin
- In most anaemias there is an increase in erythropoiesis
- Haemolytic anaemias are associated with increased reticulocyte count (baby RBCs being formed in greater numbers)
- In pernicious anaemia there is atrophy of gastric parietal cells
- Lymphoma is not associated with cold agglutinins
10
Q
- Aplastic anaemia is caused by:
- a. Arsenic
- b. Epstein-Barr virus
- c. Insecticides such as DDT
- d. Chloramphenicol
- e. All of the above
A
e. All of the above
For sure chloramphenicol and EBV (as per Wiki) so likely all of them.
11
Q
- Haemolytic anaemia
- a. Caused by intravascular haemolysis is associated with increased haptoglobin
- b. Is always associated with increased viscosity
- c. May occur with clostridial sepsis
- d. Caused by sickle cell disease is associated with splenomegaly in adults
- e. Occurs with fish tapeworm infection
A
c. May occur with clostridial sepsis
- a. Caused by intravascular haemolysis is associated with decreased haptoglobin
- b. Is always associated with increased viscosity
- d. Caused by sickle cell disease is associated with asplenia in adults
- Splenomegally as a child, but progressive ischaemia and scarring causes shrinkage until only a nubbin of spleen is left by adolescence
- e. Doesnt occur with fish tapeworm infection
- This seems to be a GI parasite solely
12
Q
- Pernicious anaemia is associated with
- a. Hepatocellular carcinoma
- b. Stomach carcinoma
- c. Colonic carcinoma
- d. Leukoplakia
- e. Squamous cell carcinoma of the genital system
A
b. Stomach carcinoma
Associated with some types of gastric cancer, but no causal link identified.
13
Q
- Regarding sickle cell anaemia
- a. Diagnosis is based on bone marrow aspirate
- b. Prenatal detection is possible through fetal DNA analysis
- c. The amount of HbC and its interactions with other chains in the cell affects the rate of sickling
- d. Dehydration does not predispose to sickling crisis
- e. 25% of black Americans are heterozygous
A
b. Prenatal detection is possible through fetal DNA analysis
- a. Diagnosis is based on blood smears and mixing with reagents to induce sickling
- c. The amount of HbS and its interactions with other chains in the cell affects the rate of sickling
- d. Dehydration does predispose to sickling crisis
- e. 8-10% of black Americans are heterozygous
14
Q
All of the following conditions are associated with polycythaemia except
- Leukaemia
- Emphysema
- Cyanotic heart disease
- Renal cell carcinoma
- Myeloproliferative disorders
A
Leukaemia
- Emphysema, cyanotic heart disease, and RCC all linked to polycythaemia*
- Polycythaemia Rubra Vera is a myeloproliferative disorder*
- Emphysema
- Cyanotic heart disease
- Renal cell carcinoma
- Myeloproliferative disorders
15
Q
Regarding ITP
- Bleeding tendency becomes clinically evident with small drops in platelet count.
- It is commonly seen in children following bacterial infections.
- Splenectomy is beneficial in up to 40% patients
- An increased number of megakaryocytes are normally seen in the bone marrow
- PT and APTT is increased.
A
An increased number of megakaryocytes are normally seen in the bone marrow
- Bleeding tendency becomes clinically evident with large drops in platelet count - <10 is bad, <50 you’d start thinking about whether you really want to put a needle into that spine
- It is commonly seen in children following viral infections.
- Splenectomy is beneficial in up to 40% patients
- Doesn’t affect coagulation tests - clotting factors still present, but less ability in vivo to create thombi.
