Anaemia And Cancers Flashcards
What is anaemia characterized by?
Reduction in Hb and Haematocrit levels
The type of anaemia is indicated by MCV.
What does Haematocrit measure?
The ratio of RBC to the volume of blood.
What does MCV stand for and what does it represent?
Mean Corpuscular Volume; it represents the average size of red blood cells and used to indicate the type of anaemia.
What is TIBC?
TIBC is total iron binding capacity, indicating how much ferritin is bound to iron.
What is RDW?
RDW is the red cell density width to indicate the variety of RBCs and their size and volume. A high RDW indicates large variety in the RBCs size and volume, between the smallest RBC and the largest RBC.
What is the normal range of haemoglobin for women?
120-160 g/dL
What is the normal range of haemoglobin for men?
135-175 g/dL
Which enzyme catalyzes the conversion of DHF to THF?
DHF reductase
What are the common causes of folate deficiency?
- Inhibition of DHF reductase by methotrexate and trimethoprim
- Inhibition of thymidylate synthase by 5-fluorouracil
- Decreased intake
- Malabsorption due to coeliac disease, alcohol abuse
- Dialysis causes folate malabsorption
- Increased utilization from pregnancy, lactation, malignancy, and haemolytic anaemia
What is the relationship between Vitamin B12 deficiency and pernicious anaemia?
Vitamin B12 deficiency is associated with autoantibodies directed to the parietal cells, causing gastritis and an increase in serum gastrin.
What characterizes microcytic anaemia?
Low MCV and Hb.
What are the most common causes of microcytic anaemia?
- Lead poisoning
- Iron deficiency
- Thalassemia
- Sideroblastic anaemia
What is the primary cause of iron deficiency anaemia?
- Dietary insufficient intake, such as greater demand in pregnancy
- Malabsorption due to coeliac’s or post-gastric surgery
- Blood loss from colon polyps, hookworm disease GI bleeding or intravascular haemolytic anaemia.
What clinical signs are associated with iron deficiency anaemia?
- Restless leg syndrome
- Koilonychia
- Pallor
- Pagophagia (compulsion to eat ice)
What does RDW indicate in the context of anaemia?
Red cell density width; a high RDW indicates a large variety in RBC size and volume.
What distinguishes iron deficiency anaemia from anaemia of chronic disease?
Soluble transferrin ferritin assay; STFR is raised in iron deficiency.
What is the primary mechanism behind anaemia of chronic disease?
Host defence theory where iron is sequestered as ferritin to be stored in cells to prevent utilisation by pathogens for growth. Inflammatory cytokines may reduce EPO production or the bone marrow’s responsiveness to EPO.
It is the most common type of anaemia in admitted hospital patients.
Clinical signs include pallor, heart murmur, angina and fatigue.
Which conditions are associated with anaemia of chronic disease?
Infections such as viral and chronic
Cancer
Autoimmune diseases
CKD and inflammation
What are the indictors on FBC of anaemia of chronic disease?
There will be reduced Hb and MCV, but MCV can also be normocytic. There will be a high serum ferritin but low serum iron.
What are the types of thalassemia?
- Thalamseemia is a defect in the globin chain of haemoglobin, split into alpha and beta thalassemia. The Hb are insoluble and precipitate in the RBCs, causing the spleen to initiate haemolysis and leading to ineffective erythropoeisis. It is divided into:
- Alpha thalassemia
- Beta thalassemia
What is alpha thalassemia?
Alpha thalassemia is associated with a defect in either of the 4 alleles, and defect in one is asymptomatic while defect in all 4 results in hydrops fetalis, with severe swelling of the newborn.
What is beta thalassemia?
Beta thalassemia results from point nonsense mutations and can be heterozygous and cause minor Microcytic anaemia Homozygous beta thalassemia causes severe anaemia, with only alpha haemoglobin remaining and causing precipitating of RBCs and inducing haemolysis, eventually leading to jaundice and hepatosplenomegaly
What is sideroblastic anaemia caused by?
Deficiency in haem synthesis of protoporphyrin. failing to combining with Fe (iron) to make haem + globin -> haemoglobin. Therefore, there is failure to incorporate iron into haemoglobin.
What does FBC show for sideroblastic anaemia?
Blood count shows low Hb, MCV and a rise in iron due to defect in protoporphyrin. There is a high ferritin and RDW.