Hematopathology Practice Questions

Q: Retention of mature neutrophils in bone marrow is known as:

Myelokathesis. **Explanation:** **1. Why Myelokathesis is correct:** **Myelokathesis** (from the Greek *myelo* meaning marrow and *kathesis* meaning retention) is a rare congenital disorder characterized by severe chronic leukopenia and neutropenia. The underlying pathophysiology involves a mutation in the **CXCR4 receptor** gene. Normally, the interaction between CXCR4 on neutrophils and CXCL12 (SDF-1) in the bone marrow keeps precursors in the niche; a "gain-of-function" mutation causes excessive signaling, preventing mature neutrophils from exiting the marrow into the peripheral blood. On a bone marrow aspirate, this manifests as hypercellularity with an abundance of mature, often apoptotic-looking neutrophils (senescent changes like pyknotic nuclei and long filaments connecting nuclear lobes). **2. Why other options are incorrect:** * **Myelocytosis:** This is a general term referring to an increase in myeloid cells (specifically myelocytes) in the blood or bone marrow, often seen in leukemoid reactions or CML. * **Leukocytosis:** This refers to an elevated white blood cell count in the peripheral blood, which is the opposite of what occurs in myelokathesis. * **Leukemia:** This is a malignant proliferation of hematopoietic stem cells leading to the replacement of normal marrow with neoplastic cells (blasts or mature cells), not a retention defect of normal mature cells. **3. High-Yield Clinical Pearls for NEET-PG:** * **WHIM Syndrome:** Myelokathesis is a key component of the WHIM syndrome triad: **W**arts (HPV), **H**ypogammaglobulinemia, **I**nfections, and **M**yelokathesis. * **Genetics:** Look for **CXCR4** gene mutations in clinical vignettes. * **Morphology:** "Hypersegmented" or "pyknotic" neutrophils in a hypercellular marrow despite peripheral neutropenia is the classic diagnostic clue.

Q: Reticulocytosis is NOT a feature of which of the following conditions?

Anemia in chronic renal failure (CRF). **Explanation:** The **Reticulocyte Count** is a direct indicator of the bone marrow's erythropoietic activity. To produce reticulocytes, the marrow requires two things: a functional stimulus (Erythropoietin) and a healthy "factory" (bone marrow). **Why Option D is Correct:** In **Chronic Renal Failure (CRF)**, the primary cause of anemia is the **deficiency of Erythropoietin (EPO)**, which is produced by the peritubular interstitial cells of the kidney [1]. Without EPO, the bone marrow is not stimulated to produce new red cells despite the anemia. Therefore, CRF is characterized by a **hypoproliferative anemia** with a low reticulocyte count (reticulocytopenia) [1]. **Why the other options are incorrect:** * **A. Paroxysmal Nocturnal Hemoglobinuria (PNH):** This is an acquired hemolytic anemia. In response to the destruction of RBCs, a healthy bone marrow compensates by increasing RBC production, leading to reticulocytosis. * **B. Acute Bleeding:** Following a sudden loss of blood, the body increases EPO production to replace the lost volume, resulting in a physiological rise in reticulocytes within 3–5 days. * **C. Hereditary Spherocytosis:** This is a congenital hemolytic anemia due to membrane defects. The marrow remains hyperactive to compensate for the shortened lifespan of the spherocytes, resulting in a high reticulocyte count. **High-Yield Clinical Pearls for NEET-PG:** * **Corrected Reticulocyte Count (CRC):** In anemia, always use CRC to assess marrow response. $CRC = \text{Observed Retic \%} \times (\text{Patient Hct} / \text{Normal Hct})$. * **Reticulocyte Production Index (RPI):** An RPI > 2% indicates an adequate marrow response (hemolysis/hemorrhage); RPI < 2% indicates an inadequate response (nutritional deficiency/marrow failure). * **Other causes of Reticulocytopenia:** Iron/B12/Folate deficiency, Aplastic anemia, and Bone marrow suppression (e.g., chemotherapy).

Q: What is the typical Vitamin B level in chronic myeloid leukemia?

Elevated. **Explanation:** In Chronic Myeloid Leukemia (CML), serum Vitamin B12 levels are characteristically **elevated**, often reaching several times the normal limit. This occurs due to the massive expansion of the granulocytic series (neutrophils and their precursors). These cells synthesize and secrete **Transcobalamin I (TCI)**, an R-binder protein responsible for transporting Vitamin B12 in the plasma. As the total white blood cell count rises, the concentration of TCI increases proportionally, leading to an increased total B12 binding capacity and elevated serum B12 levels. **Analysis of Options:** * **Option A (Correct):** Elevated levels are a classic biochemical marker of CML due to increased Transcobalamin I production by leukemic cells. * **Option B & D (Incorrect):** Decreased levels are seen in megaloblastic anemias (pernicious anemia, dietary deficiency). In CML, despite high serum levels, there is often "functional" deficiency because the B12 is tightly bound to TCI and less available for tissue uptake. * **Option C (Incorrect):** Normal levels are rare in untreated CML with high tumor burden. **High-Yield Clinical Pearls for NEET-PG:** * **Transcobalamin I (TCI):** Derived from specific granules of granulocytes; elevated in CML. * **Transcobalamin II (TCII):** The primary protein responsible for delivering B12 to tissues (liver, bone marrow). * **LAP Score:** In CML, the Leukocyte Alkaline Phosphatase (LAP) score is characteristically **low**, helping differentiate it from a Leukemoid Reaction (where LAP is high). * **Uric Acid:** Also frequently elevated in CML due to high cell turnover [1].

Q: Which test is used for the detection of the intrinsic pathway of coagulation?

Activated Partial Thromboplastin Time (aPTT). **Explanation:** The coagulation cascade is divided into the intrinsic, extrinsic, and common pathways. The **Activated Partial Thromboplastin Time (aPTT)** is the specific screening test used to evaluate the **intrinsic pathway** (Factors XII, XI, IX, VIII) and the **common pathway** (Factors X, V, II, I). It measures the time taken for a fibrin clot to form after adding an activator (like kaolin or silica) and phospholipids to the plasma. **Analysis of Options:** * **Prothrombin Time (PT):** This tests the **extrinsic pathway** (Factor VII) and the common pathway. It is the investigation of choice for monitoring Warfarin therapy and assessing liver function. * **Bleeding Time (BT):** This measures **primary hemostasis**, specifically platelet function and vascular integrity, rather than the coagulation cascade. It is prolonged in conditions like Von Willebrand Disease and Thrombocytopenia. * **Clotting Time (CT):** While it measures the time for blood to clot, it is a crude, non-specific bedside test (e.g., Lee-White method) that lacks the sensitivity and standardization of aPTT. **High-Yield Clinical Pearls for NEET-PG:** * **Heparin Monitoring:** aPTT is the gold standard for monitoring unfractionated heparin therapy. * **Hemophilia:** Both Hemophilia A (Factor VIII deficiency) and Hemophilia B (Factor IX deficiency) result in an **isolated prolonged aPTT** with a normal PT and BT. * **Vitamin K Deficiency:** Initially prolongs PT (due to the short half-life of Factor VII) before affecting aPTT. * **Mixing Studies:** If aPTT is prolonged, a mixing study is done; correction indicates factor deficiency, while non-correction suggests an inhibitor (e.g., Lupus anticoagulant).

Question 1

Retention of mature neutrophils in bone marrow is known as:

Accepted Answer

Myelokathesis

Answer

Myelocytosis

Answer

Leukocytosis

Answer

Leukemia

Question 2

Which of the following conditions is inherited in an autosomal recessive pattern?

Accepted Answer

Sickle cell anemia

Answer

Hemophilia

Answer

Hereditary spherocytosis

Answer

Glucose 6-phosphate dehydrogenase deficiency

Question 3

What is the most common subtype of ALL (Acute Lymphoblastic Leukemia)?

Accepted Answer

Pre B cell ALL

Answer

Pre T cell ALL

Answer

T cell ALL

Answer

B cell ALL

Question 4

Which of the following is NOT related to blood coagulation disorders in obstetrics?

Accepted Answer

Thrombocytopenia is a feature of the fibrinolytic process and not of DIC.

Answer

In DIC, RBCs will be 'helmet' shaped or fragmented; in the fibrinolytic process, cell morphology is nominal.

Answer

The Weiner clot observation test gives a rough estimate of the total blood fibrinogen level.

Answer

Thrombocytopenia can be diagnosed from the peripheral smear.

Question 5

Reticulocytosis is NOT a feature of which of the following conditions?

Accepted Answer

Anemia in chronic renal failure (CRF)

Answer

Paroxysmal nocturnal hemoglobinuria

Answer

Following acute bleeding

Answer

Hereditary spherocytosis

Question 6

What is the typical Vitamin B level in chronic myeloid leukemia?

Accepted Answer

Elevated

Answer

Decreased

Answer

Normal

Answer

Markedly decreased

Question 7

Translocation (8;14) is characteristic of which of the following conditions?

Accepted Answer

Burkitt's lymphoma

Answer

Ataxia telangiectasia

Answer

Acute lymphoblastic leukemia (ALL)

Answer

Chronic myeloid leukemia (CML)

Question 8

What are the essential WHO criteria for polycythemia vera?

Accepted Answer

Tyrosine kinase JAK2 V617F and other mutations

Answer

Low levels of erythropoietin

Answer

Thrombocytosis

Answer

Increased MCV

Question 9

Reilly bodies are seen in which of the following conditions?

Accepted Answer

Hurler disease

Answer

Gangliosidosis

Answer

Behcet's disease

Answer

Gaucher's disease

Question 10

Which test is used for the detection of the intrinsic pathway of coagulation?

Accepted Answer

Activated Partial Thromboplastin Time (aPTT)

Answer

Prothrombin Time (PT)

Answer

Bleeding Time (BT)

Answer

Clotting Time (CT)

Hematopathology — MCQs

Hematopathology — MCQs

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