MCQ – Microcytic Anaemia

1. Which of the following diagnosis can be excluded by the presence of microcytosis

  1. Aplastic anaemia
  2. Iron deficiency
  3. Paroxysmal nocturnal haemoglobinuria
  4. Sideroblastic anaemia

2. Which of the following are true about thalassaemia

  1. Thalassaemia results from mutations in the β-globin gene
  2. Severe forms of Beta-thalassaemia presents at birth
  3. Patients of β-thalassaemia major develop iron overload only when over transfused
  4. Thalassaemia are seen in regions of the world that have or had malaria

3. Which of the following about iron therapy is true

  1. It is recommended that iron be taken after food
  2. Enteric coated reduce toxicity while maintaining efficacy
  3. About 150-200mg of elemental iron should be administered in divided doses
  4. Ferrous sulphate the preparation of choice because it is the most effective

4. Which of the following is seen in iron deficiency

  1. Low serum iron, low total iron binding capacity normal transferrin saturation
  2. Low serum iron, high total iron binding capacity, low transferrin saturation
  3. Low serum iron, low total iron binding capacity, low transferrin saturation
  4. Any of the above

5. Which of the following changes are seen in the haemogram of a patient of iron deficiency

  1. Anaemia
  2. Anisocytosis
  3. Thrombocytosis
  4. All of the above

 

 

Answers

Question 1

Right Choice A. Aplastic anaemia is normocytic to macrocyctic

Why not other options

  • B. Iron deficiency is hypochromic microcytic with low ion stores
  • C. Paroxysmal nocturnal haemoglobinuria is characterised by intravascular haemolysis our to increased sensitivity to complement mediated lysis. Urinary loss of iron due to haemoglobinuria may result in iron deficiency and consequently microcytosis
  • D. A common form of sideroblastic anaemia X-linked sideroblastic anaemia (XLSA) is characterised by microcytosis. XLSA should be considered in patient with microcytosis in whom iron deficiency and thalassaemia can be excluded.

Question 2

Right Choice. D. Thalassaemias is found in areas where malaria is or was endemic. The region extends from southern Europe to southeast Asia and includes Africa, middle east and south Asia. It is very uncommon to find thalassaemia causing mutations outside this area. It has been postulated that thalassaemias trait protects against serious forms of falciparum malaria that gives individuals with thalassaemia trait a survival advantage. This is also postulated to be the reason for the high prevalence on the same region of hemoglobinopathies like HbS, HbC, G6PD deficiency and some membrane defects e.g. Southeast Asian ovalocytosis.

Why not other options

  • A. In addition to mutations of β genes mutations thalassaemia mutations may involve
      1. genes for α, γ, δ and ε globing chains
      2. DNA segments regulating the expression of globin genes
  • B. HbA production reaches adult levels by 6 months. β-Thalassaemia results from a defect in the synthesis of β-globin gene resulting in an impairment of HbA synthesis. HbF constitutes 80% of haemoglobin at birth and HbA 20%. HbA levels increase to adult levels by the age of six months. β-Thalassaemia manifests when HbA is expected to constitute the major haemoglobin. Patients do not have symptoms in the first few months of life
  • C. Iron overload is the main cause of morbidity and mortality of thalassaemia. Non-transfused patients have iron overload from increased iron absorption due to suppression of hepcidin because of increased erythropoiesis and anaemia. In transfused patients there is additional iron overload of transfusion. Non-transfused patients are growth retarded, have bone anomalies and organomegaly. A transfusion regimen prevents these complications and is the practice despite the iron overload it causes. Iron chelation therapy is used in patients of thalassaemia to prevent iron overload.

Question 3

Right Choice C. The recommended dose of iron is 150-200mg elemental iron per day in divided doses.

Why not other options

  • A. Food hampers iron absorption but may improve the gastrointestinal tolerance of iron. Iron may be administered after food in patients with intolerance at the cost of reduced absorption. The recommended way to administered iron is 1 hour before or 2 hours after meals.
  • B. Iron absorption takes place in the duodenum and upper jejunum. Enteric coated preparation are used to reduce gastrointestinal intolerance. These preparations may release iron too late, beyond the part of the gut iron is best absorbed.
  • D. There is little evidence that a particular preparation of iron is better than the other. Ferrous sulphate is the cheapest and hence the salt of choice for iron supplementation

Question 4

Right Choice B. Iron deficiency is characterised by low serum iron high total iron binding capacity and low and a low (<16%) transferrin saturation.

Why not other options

  • A. Transferrin levels fall with inflammation. Hepcidin levels rise hampering release of iron from macrophages. Low total iron binding capacity in and anaemic patients is seen in patients with anaemia of chronic disease.
  • C. Low transferrin saturation with low serum iron suggests iron deficiency with anaemia of chronic disease.

Question 5

Right Choice D. All are features of iron deficiency

Why not other options

  • A. Iron deficiency is the commonest cause of iron deficiency
  • B. Anisocytosis is variation in cell size. Anisocytosis differentiates iron deficiency from thalassaemia. Both are microcytic. Iron deficiency shows anisocytosis. Thalassaemias do not.
  • C. Thromboctosis is a feature of 30-60% of iron deficiency anaemias. The platelet counts are likely to increase as the haemoglobin falls. Thrombocytosis resolves within 4 weeks of iron therapy in most patients (Blood 2006 108:3723)
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