Hematopathology Practice Questions

Q: Pancytopenia with hypercellular bone marrow is seen in which of the following conditions?

Megaloblastic anemia. **Explanation:** The hallmark of **Megaloblastic Anemia** is "ineffective hematopoiesis." In this condition (usually due to Vitamin B12 or Folate deficiency), there is a defect in DNA synthesis while RNA synthesis remains intact. This leads to nuclear-cytoplasmic asynchrony, where cells grow large but cannot divide properly [1]. Consequently, the bone marrow is **hypercellular** because it is packed with megaloblasts, but these cells undergo intramedullary destruction (apoptosis) before reaching maturity. This results in a decrease in all three cell lines in the peripheral blood (**Pancytopenia**). **Analysis of Incorrect Options:** * **Paroxysmal Nocturnal Hemoglobinuria (PNH):** While PNH can present with pancytopenia, it is typically associated with a **hypocellular** marrow (often overlapping with Aplastic Anemia) or a normocellular marrow with erythroid hyperplasia if hemolysis is the primary feature. * **Acquired Aplastic Anemia:** This is the classic cause of pancytopenia, but the bone marrow is characteristically **hypocellular** (replaced by fat cells). * **Thalassemia:** This typically presents with microcytic hypochromic anemia and erythroid hyperplasia in the marrow, but it does not usually cause generalized pancytopenia. **High-Yield Clinical Pearls for NEET-PG:** * **Differential Diagnosis of Pancytopenia with Hypercellular Marrow:** Megaloblastic anemia, Myelodysplastic Syndrome (MDS), and Aleukemic Leukemia. * **Peripheral Smear:** Look for macro-ovalocytes and **hypersegmented neutrophils** (>5 lobes) [1]. * **Biochemical Markers:** Elevated LDH and Indirect Bilirubin (due to ineffective hematopoiesis/intramedullary hemolysis). **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 593-594.

Q: What is the antibody responsible for heparin-induced thrombocytopenia?

Antiheparin/PF4 antibody. ### Explanation **Heparin-Induced Thrombocytopenia (HIT)** is a life-threatening clinico-pathological syndrome caused by an immune response to heparin therapy. **1. Why Option A is correct:** The pathogenesis of HIT (specifically Type II) involves the formation of IgG antibodies against a complex of **Heparin and Platelet Factor 4 (PF4)**. PF4 is a cationic protein released from the alpha-granules of activated platelets. When heparin (anionic) binds to PF4, it creates a neoantigen. The resulting **IgG-Heparin-PF4 immune complexes** bind to the **FcγRIIa receptors** on the surface of platelets. This leads to: * **Platelet Activation:** Causing the release of procoagulant microparticles (leading to thrombosis). * **Platelet Consumption:** Leading to thrombocytopenia. **2. Why the other options are incorrect:** * **Option B (PF2):** Platelet Factor 2 is involved in fibrinogen sensitization but has no role in the pathogenesis of HIT. * **Option C (GP IIb/IIIa):** These are targets for antibodies in **Immune Thrombocytopenic Purpura (ITP)** and are the site of action for drugs like Abciximab. * **Option D (GP Ib/IX):** This is the Von Willebrand Factor (vWF) receptor. Deficiencies lead to **Bernard-Soulier Syndrome**, and it is also a target in some cases of ITP, but not HIT. **3. High-Yield Clinical Pearls for NEET-PG:** * **Timing:** Typically occurs **5–10 days** after starting heparin. * **Paradox:** Despite low platelet counts, HIT is a **pro-thrombotic state** (venous > arterial thrombosis). * **Diagnosis:** Screen with ELISA (high sensitivity); confirm with **Serotonin Release Assay (SRA)** (Gold Standard/High specificity). * **Management:** Immediately stop all heparin. Start alternative anticoagulants like **Argatroban** (Direct Thrombin Inhibitor) or Fondaparinux. Never give platelet transfusions as they "fuel the fire."

Q: What is the level of soluble transferrin receptor in iron deficiency anemia?

Increased. **Explanation:** **1. Why the Correct Answer (A) is Right:** Soluble Transferrin Receptor (sTfR) is a truncated form of the membrane-bound transferrin receptor found on the surface of erythroid precursor cells. Its concentration in the serum is directly proportional to the total number of transferrin receptors on these cells [1]. When intracellular iron levels drop—as seen in **Iron Deficiency Anemia (IDA)**—the cell upregulates the expression of transferrin receptors to capture as much iron as possible from the circulation [1]. Consequently, the level of sTfR increases significantly. This makes sTfR a sensitive marker for iron-deficient erythropoiesis. **2. Why Other Options are Wrong:** * **B. Decreased:** sTfR levels decrease in conditions where erythropoiesis is suppressed (e.g., aplastic anemia or chronic renal failure) or in states of iron overload (e.g., hemochromatosis), where cells downregulate receptors. * **C. Normal:** sTfR levels remain **normal in Anemia of Chronic Disease (ACD)**. This is the most critical clinical distinction, as ACD is characterized by iron sequestration rather than a true systemic deficit [1]. **3. NEET-PG High-Yield Pearls:** * **The "Gold Standard" Utility:** The sTfR assay is the most reliable test to differentiate between **IDA (Increased sTfR)** and **ACD (Normal sTfR)**, especially when ferritin levels are falsely elevated due to inflammation (as ferritin is an acute-phase reactant). * **sTfR-Ferritin Index:** A high index (sTfR/log Ferritin) is highly suggestive of IDA. * **Independence:** Unlike ferritin, sTfR levels are **not** affected by systemic inflammation, infection, or liver disease, making it a "cleaner" marker for marrow iron status. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 657-658.

Q: Which of the following is a common blood transfusion reaction?

Febrile nonhemolytic transfusion reaction. **Explanation:** **Correct Answer: A. Febrile nonhemolytic transfusion reaction (FNHTR)** FNHTR is the **most common** adverse reaction associated with the transfusion of blood products. It is defined as a rise in temperature of $\geq 1^\circ\text{C}$ during or shortly after transfusion, without any other explainable cause. * **Mechanism:** It is primarily caused by **preformed cytokines** (like IL-1, IL-6, and TNF-$\alpha$) that accumulate in the stored blood component or by recipient antibodies reacting against donor white blood cells (HLA antigens). * **Prevention:** The incidence has significantly decreased due to the routine use of **leukoreduction** (filtering out WBCs before storage). **Incorrect Options:** * **B. Hemolysis:** Acute hemolytic reactions (usually due to ABO incompatibility) are life-threatening but **rare** due to strict cross-matching protocols [1]. * **C. Transmission of infections:** With modern nucleic acid testing (NAT) and rigorous screening for HIV, Hepatitis B, and C, the risk of transfusion-transmitted infections is now extremely low. * **D. Electrolyte imbalance:** While complications like hyperkalemia or hypocalcemia (citrate toxicity) can occur, they are typically seen only in **massive transfusions** and are not common in routine single-unit transfusions. **NEET-PG High-Yield Pearls:** * **Most common overall reaction:** Febrile nonhemolytic transfusion reaction. * **Most common cause of transfusion-related death:** TRALI (Transfusion-Related Acute Lung Injury). * **Most common infectious risk:** Bacterial contamination (especially in **Platelets**, as they are stored at room temperature). * **Management of FNHTR:** Stop transfusion, rule out hemolysis, and administer antipyretics (Acetaminophen). [1] **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 673-674.

Q: Which of the following is best to confirm the diagnosis of thalassemia trait in a patient with a positive family history of thalassemia?

Elevated HbA2. **Explanation:** **1. Why Elevated HbA2 is the Correct Answer:** The hallmark of **Beta-Thalassemia Trait (Minor)** is a quantitative deficiency in beta-globin chain synthesis. To compensate for the lack of beta chains, there is a relative increase in delta-chain production, which combines with alpha chains to form **Hemoglobin A2 (α2δ2)**. * **Diagnostic Gold Standard:** High-Performance Liquid Chromatography (HPLC) or Hemoglobin Electrophoresis is used to quantify Hb levels. * **Cut-off:** An **HbA2 level >3.5%** is considered diagnostic for Beta-Thalassemia Trait. HbF may also be slightly elevated (1–5%), but HbA2 is the more reliable confirmatory marker. **2. Why Other Options are Incorrect:** * **NESTROFT (Naked Eye Single Tube Red Cell Osmotic Fragility Test):** This is a highly sensitive **screening test** used in field surveys and mass screenings due to its low cost. However, it is not confirmatory as it can be positive in other conditions like iron deficiency anemia (IDA). * **Peripheral Smear:** While it shows characteristic microcytic hypochromic cells, target cells, and basophilic stippling, these findings are non-specific and overlap significantly with IDA. * **Reticulocytosis:** In thalassemia trait, the reticulocyte count is usually normal or only slightly elevated. Significant reticulocytosis is more characteristic of Thalassemia Major or Intermedia. **3. NEET-PG Clinical Pearls:** * **Mentzer Index:** (MCV/RBC count). If ** 13**, it suggests Iron Deficiency Anemia. * **RBC Count:** In Thalassemia trait, the RBC count is typically **elevated** (polycythemia) despite low hemoglobin, whereas in IDA, the RBC count is low. * **Differential Diagnosis:** Always rule out IDA before diagnosing Thalassemia trait, as iron deficiency can falsely lower HbA2 levels, potentially masking a Thalassemia diagnosis.

Question 1

Pancytopenia with hypercellular bone marrow is seen in which of the following conditions?

Accepted Answer

Megaloblastic anemia

Answer

Paroxysmal nocturnal hemoglobinuria (PNH)

Answer

Acquired aplastic anemia

Answer

Thalassemia

Question 2

What is the antibody responsible for heparin-induced thrombocytopenia?

Accepted Answer

Antiheparin/PF4 antibody

Answer

Antiheparin/PF2 antibody

Answer

Antiheparin/GP IIb/IIIa antibody

Answer

Antiheparin GP Ib/IX antibody

Question 3

Which of the following is a cause of extravascular hemolysis?

Accepted Answer

Sickle cell disease

Answer

Falciparum malaria

Answer

Mismatched blood transfusion

Answer

Microthrombi in circulation

Question 4

In acute myeloid leukemia, Auer rods are numerous in which subtype?

Accepted Answer

M3

Answer

M2

Answer

M4

Answer

M5

Question 5

What is the level of soluble transferrin receptor in iron deficiency anemia?

Accepted Answer

Increased

Answer

Decreased

Answer

Normal

Answer

None

Question 6

Atypical lymphocytosis is most likely to be found in which one of the following diseases?

Accepted Answer

Infectious mononucleosis induced by Epstein-Barr virus

Answer

Encephalitis caused by herpes simplex virus (HSV)

Answer

Parvovirus infection

Answer

Chronic hepatitis C

Question 7

Which of the following is a common blood transfusion reaction?

Accepted Answer

Febrile nonhemolytic transfusion reaction

Answer

Hemolysis

Answer

Transmission of infections

Answer

Electrolyte imbalance

Question 8

The diagnostic triad of exophthalmos, diabetes insipidus, and bone lesions is characteristic of which condition?

Accepted Answer

Hand-Schuller Christian disease

Answer

Fibrous dysplasia

Answer

Letterer-Sieve disease

Answer

Osteoporosis

Question 9

Which of the following is best to confirm the diagnosis of thalassemia trait in a patient with a positive family history of thalassemia?

Accepted Answer

Elevated HbA2

Answer

Reticulocytosis

Answer

NESTROFT

Answer

Peripheral smear

Question 10

A patient presents with splenomegaly, low RBC count, normal WBC and platelet count, and peripheral blood smear shows target cells. Repeated bone marrow aspiration is unsuccessful. What is the probable diagnosis?

Accepted Answer

Myelofibrosis

Answer

Thalassemia

Answer

Chronic myeloid leukemia

Answer

Iron deficiency anemia

Hematopathology — MCQs

Hematopathology — MCQs

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