Aplastic and hypoproliferative anemias

5 DOH Abu Dhabi (HAAD) lab licensing practice questions on Aplastic and hypoproliferative anemias, part of Hematology. The first 5 are below; the first 5 with answers and explanations (tap Show answer after you have chosen), the rest in Learn with a free account.

1. Question 1 · Easy

   Before treatment, the anemia of chronic kidney disease is typically:

   1. AMacrocytic, with hypersegmented neutrophils
   2. BNormocytic, with spherocytes and high reticulocytes
   3. CNormocytic and normochromic, with low reticulocytes
   4. DMicrocytic and hypochromic, with high reticulocytes

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   Answer: C · Normocytic and normochromic, with low reticulocytes

   Damaged kidneys make too little erythropoietin for the degree of anemia, so the marrow underproduces red cells of normal size and color. The reticulocyte count is inappropriately low, and burr cells may be seen in uremia. Iron deficiency often coexists, for example from blood loss on dialysis, and can lower the MCV. Iron studies are therefore checked before an erythropoiesis-stimulating agent is started.

   • A: Macrocytosis with hypersegmented neutrophils points to B12 or folate deficiency.
   • B: Spherocytes with a reticulocytosis indicate hemolysis, not underproduction.
   • D: Microcytosis with a high reticulocyte count fits thalassemia trait or treated iron deficiency, not a lack of erythropoietin.

2. Question 2 · Medium

   In a patient with pancytopenia, which finding argues most strongly against aplastic anemia?

   1. AMacrocytosis with an MCV of 102 fL
   2. BMarked splenomegaly
   3. CA raised serum erythropoietin
   4. DA low absolute reticulocyte count

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   Answer: B · Marked splenomegaly

   Aplastic anemia is a failure of the stem cells themselves, so the spleen, liver and lymph nodes are not enlarged. Pancytopenia with splenomegaly suggests hypersplenism, marrow infiltration such as hairy cell leukemia or lymphoma, or myelofibrosis. In aplastic anemia the reticulocyte count is low, erythropoietin is high and the red cells are often slightly macrocytic. A trephine biopsy then confirms a fatty marrow with no abnormal cells.

   • A: Mild macrocytosis is common in aplastic anemia.
   • C: Erythropoietin rises appropriately in aplastic anemia because the kidneys sense the anemia.
   • D: A low reticulocyte count is expected when the marrow is failing.

3. Question 3 · Hard

   A 58-year-old man on hemodialysis has had an erythropoiesis-stimulating agent for 3 months, but his hemoglobin stays at 91 g/L (9.1 g/dL). Results: MCV 84 fL, reticulocytes 38 × 10^9/L, ferritin 320 µg/L (320 ng/mL), transferrin saturation 13%, CRP normal, B12 and folate normal. In dialysis patients, ferritin of 200 µg/L or less with saturation of 20% or less is taken as absolute iron deficiency. What best explains the poor response?

   1. AFunctional iron deficiency
   2. BAnti-erythropoietin antibodies
   3. CAnemia of inflammation
   4. DAbsolute iron deficiency

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   Answer: A · Functional iron deficiency

   Erythropoietin therapy drives red cell production faster than iron can be released from stores, so iron supply to the marrow becomes limiting even though stores are adequate. This is functional iron deficiency: a transferrin saturation of 20% or less with a ferritin above the absolute-deficiency cut-off. Intravenous iron usually restores the response. The normal CRP argues against inflammation, and a reticulocyte count of 38 × 10^9/L argues against antibody-mediated pure red cell aplasia, where reticulocytes are almost absent.

   • B: Anti-erythropoietin antibodies cause pure red cell aplasia with almost no reticulocytes.
   • C: With a normal CRP, inflammation is an unlikely cause of the low iron supply.
   • D: Absolute deficiency needs a ferritin of 200 µg/L or less; this ferritin is 320 µg/L.

4. Question 4 · Easy

   In suspected aplastic anemia, marrow cellularity is best judged on which sample?

   1. AA peripheral blood film
   2. BA trephine core biopsy
   3. CA marrow clot section
   4. DAn aspirate smear

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   Answer: B · A trephine core biopsy

   Aplastic marrow is fatty and often patchy, and aspirates are usually dilute with few particles, so they misjudge cellularity. A trephine biopsy of adequate length keeps the marrow architecture and shows the ratio of hematopoietic tissue to fat. It also shows infiltration or fibrosis, which can cause a dry tap and mimic marrow failure. Cellularity below 25% supports aplastic anemia.

   • A: The blood film shows the cytopenias but cannot show marrow cellularity.
   • C: A clot section depends on aspirated particles and can misrepresent a patchy marrow.
   • D: Aspirates in aplastic anemia are often dilute and particle-poor, so cellularity is unreliable.

5. Question 5 · Medium

   A 62-year-old woman with a thymoma has hemoglobin 68 g/L (6.8 g/dL), reticulocytes 3 × 10^9/L, and normal WBC and platelet counts. Her marrow has normal granulocytes and megakaryocytes but almost no erythroid precursors. This picture fits:

   1. AAnemia of chronic kidney disease
   2. BMyelodysplastic syndrome with low blasts
   3. CAplastic anemia
   4. DAcquired pure red cell aplasia

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   Answer: D · Acquired pure red cell aplasia

   Pure red cell aplasia is a selective failure of red cell production: severe normocytic anemia, almost no reticulocytes and a marrow without erythroid precursors, while the other lines are spared. Acquired cases are often immune and are linked to thymoma, large granular lymphocytic leukemia, autoimmune disease, drugs and anti-erythropoietin antibodies. Parvovirus B19 causes a transient form, sometimes with giant pronormoblasts. Aplastic anemia, by contrast, lowers all three cell lines.

   • A: Kidney disease gives a milder anemia, and erythroid precursors are still present.
   • B: MDS shows dysplasia, and erythroid precursors are usually present.
   • C: Aplastic anemia affects all three lines and leaves a fatty, hypocellular marrow.