Hematopathology — MCQs

Hematopathology Indian Medical PG Practice Questions and MCQs

Question 801: Laboratory evaluation for the differential diagnosis of chronic myeloproliferative disorders includes all of the following except?

A. Chromosomal evaluation
B. Bone marrow aspiration
C. Flow-cytometric analysis (Correct Answer)
D. Determination of red blood cell mass

Explanation: **Explanation:** Chronic Myeloproliferative Neoplasms (MPNs) are clonal hematopoietic stem cell disorders characterized by the proliferation of one or more myeloid lineages (granulocytic, erythroid, or megakaryocytic) with full differentiation [1]. **Why Flow-cytometric analysis is the correct answer:** Flow cytometry is primarily used to identify cell surface markers (CD markers) for the diagnosis of **acute leukemias** (to differentiate AML from ALL) and **lymphoproliferative disorders**. In MPNs, the cells are mature and do not show a specific "immunophenotypic signature" that aids in differential diagnosis. Therefore, it is not a routine part of the workup for MPNs. **Why the other options are incorrect:** * **Chromosomal evaluation:** Essential for identifying the **Philadelphia chromosome [t(9;22)]** or the *BCR-ABL1* fusion gene, which distinguishes Chronic Myeloid Leukemia (CML) from other MPNs (Polycythemia PV, ET, and PMF) [2]. * **Bone marrow aspiration (and biopsy):** Crucial for assessing cellularity, morphology (e.g., "staghorn" megakaryocytes in ET), and the degree of fibrosis (using reticulin stain), which are key diagnostic criteria in the WHO classification [3]. * **Determination of red blood cell mass:** Historically used to differentiate "true" Polycythemia Vera (increased mass) from relative polycythemia (decreased plasma volume) [1]. While largely replaced by JAK2 mutation testing and serum erythropoietin levels, it remains a classic laboratory parameter for MPN evaluation. **Clinical Pearls for NEET-PG:** * **JAK2 V617F mutation:** Present in >95% of Polycythemia Vera cases and ~50-60% of ET and PMF cases [2]. * **CML Hallmark:** Low Leukocyte Alkaline Phosphatase (LAP) score; other MPNs usually have a high or normal LAP score. * **Primary Myelofibrosis:** Characterized by "Dry Tap" on aspiration and "Teardrop cells" (Dacrocytes) on peripheral smear [1]. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 614-616. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of White Blood Cells, Lymph Nodes, Spleen, and Thymus, p. 624. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of White Blood Cells, Lymph Nodes, Spleen, and Thymus, pp. 626-627.

Question 802: Heavy chain disease is associated with which of the following in the urine?

A. Heavy chains (Correct Answer)
B. Seligman disease
C. Franklin disease
D. Waldenstrom macroglobulinemia

Explanation: **Explanation:** **Heavy chain diseases (HCDs)** are rare B-cell proliferative disorders characterized by the synthesis and secretion of truncated monoclonal immunoglobulin heavy chains that lack associated light chains [1]. **Why the correct answer is right:** In HCD, the plasma cells produce incomplete heavy chains (alpha, gamma, or mu) that are typically truncated due to genetic deletions. Because these heavy chains are not bound to light chains, they are relatively small and can be filtered by the glomerulus, appearing as **free heavy chains in the urine**. Unlike Multiple Myeloma, where Bence-Jones proteins (free light chains) are found, HCD is specifically defined by the presence of these isolated heavy chains. **Analysis of Incorrect Options:** * **B & C (Seligman and Franklin disease):** These are specific *types* of heavy chain diseases, not substances found in the urine. **Franklin disease** refers to Gamma-HCD (associated with lymphadenopathy and palatal edema), while **Seligman disease** refers to Alpha-HCD (the most common type, involving the GI tract/IPSID). While these diseases *cause* heavy chains in the urine, they are the clinical diagnoses themselves. * **D (Waldenstrom Macroglobulinemia):** This is a plasma cell dyscrasia characterized by the production of monoclonal **IgM** (a complete pentameric immunoglobulin) [1]. It typically presents with hyperviscosity and does not feature isolated heavy chains in the urine. **NEET-PG High-Yield Pearls:** * **Alpha-HCD (Seligman Disease):** Most common HCD; associated with Mediterranean lymphoma and malabsorption. * **Gamma-HCD (Franklin Disease):** Presents like a lymphoma; unique clinical sign is **palatal erythema/edema** due to involvement of Waldeyer’s ring. * **Diagnosis:** Confirmed by **Immunofixation Electrophoresis (IFE)** showing a monoclonal band of heavy chains without a corresponding light chain band. * **Key Distinction:** Bence-Jones protein = Light chains (Myeloma); HCD = Heavy chains. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of White Blood Cells, Lymph Nodes, Spleen, and Thymus, pp. 606-607.

Question 803: Which of the following viruses is implicated in the pathogenesis of Hodgkin's disease?

A. Hepatitis C Virus (HCV)
B. Human Papillomavirus (HPV)
C. Epstein-Barr Virus (EBV) (Correct Answer)
D. Human Immunodeficiency Virus (HIV)

Explanation: **Explanation:** **Epstein-Barr Virus (EBV)** is the correct answer as it plays a pivotal role in the pathogenesis of Hodgkin Lymphoma (HL), particularly the **Mixed Cellularity** subtype and cases associated with HIV. EBV infects B-cells and introduces the **LMP-1 (Latent Membrane Protein-1)** oncogene [4]. LMP-1 mimics CD40 signaling, activating the **NF-κB and JAK/STAT pathways**, which rescues "crippled" germinal center B-cells from apoptosis, leading to the formation of characteristic Reed-Sternberg (RS) cells. **Analysis of Incorrect Options:** * **Hepatitis C Virus (HCV):** Primarily associated with B-cell Non-Hodgkin Lymphomas (NHL), specifically **Marginal Zone Lymphoma** and Cryoglobulinemia, rather than Hodgkin’s disease [3]. * **Human Papillomavirus (HPV):** Strongly linked to squamous cell carcinomas of the cervix, anus, and oropharynx, but has no established role in lymphomagenesis [1], [3]. * **Human Immunodeficiency Virus (HIV):** While HIV patients have a much higher incidence of HL, the virus is not the direct oncogenic driver [1], [2]. Instead, HIV causes immunosuppression that allows **EBV** to drive the malignant transformation [2]. **High-Yield Clinical Pearls for NEET-PG:** * **EBV Association:** Highest in Mixed Cellularity (70-80%) and Lymphocyte Depleted subtypes; lowest in Nodular Sclerosis (~10-20%). * **RS Cell Markers:** Classic HL cells are typically **CD15+ and CD30+** (CD45 negative). * **LMP-1:** This is the specific EBV protein used as a diagnostic marker in immunohistochemistry to confirm EBV-positive status in biopsy samples [4]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 261-262. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 262-263. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 219-220. [4] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Neoplasia, pp. 335-336.

Question 804: A patient presents with persistent fever and significant weight loss for two months. Examination reveals cervical and axillary lymphadenopathy. Biopsy of cervical nodes is positive for Hodgkin's Lymphoma. What is the clinical stage of the patient?

A. Stage II A
B. Stage II B (Correct Answer)
C. Stage III A
D. Stage IV B

Explanation: ### Explanation The clinical staging of Hodgkin’s Lymphoma (HL) is determined using the **Ann Arbor Staging System** (modified by the Cotswolds criteria). **1. Why Stage II B is correct:** * **Stage II:** The patient has involvement of two or more lymph node regions (cervical and axillary) on the **same side of the diaphragm** (both are above the diaphragm) [1], [2]. * **Suffix "B":** The presence of systemic symptoms—specifically **persistent fever** and **significant weight loss** (>10% of body weight in 6 months)—classifies the disease as "B" [1]. If these symptoms were absent, it would be "A." **2. Why the other options are incorrect:** * **Stage II A:** Incorrect because the patient exhibits "B symptoms" (fever and weight loss) [1]. * **Stage III A:** Incorrect because Stage III requires involvement of lymph node regions on **both sides** of the diaphragm (e.g., cervical and inguinal nodes). "A" denotes the absence of B symptoms. * **Stage IV B:** Incorrect because Stage IV involves **diffuse extranodal involvement** (e.g., liver, bone marrow, or lungs) beyond just the lymph nodes. **3. NEET-PG High-Yield Pearls:** * **B Symptoms:** Include drenching night sweats, unexplained fever (>38°C), and weight loss (>10% in 6 months) [1]. Their presence usually indicates a poorer prognosis. * **Diaphragm Rule:** The landmark for Ann Arbor staging. Above only = Stage I/II; Both sides = Stage III; Disseminated = Stage IV. * **Bulky Disease:** Defined as a nodal mass >10 cm or >1/3rd of the transthoracic diameter. * **Most Common Subtype:** Nodular Sclerosis is the most common subtype of Classical HL [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of White Blood Cells, Lymph Nodes, Spleen, and Thymus, pp. 616-618. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of White Blood Cells, Lymph Nodes, Spleen, and Thymus, p. 618.

Question 805: Vitamin B12 deficiency results in which type of anemia?

A. Aplastic anemia
B. Iron deficiency anemia
C. Anemia of chronic disease
D. Macrocytic anemia (Correct Answer)

Explanation: **Explanation:** **Correct Option: D. Macrocytic anemia** Vitamin B12 (Cobalamin) and Folic acid are essential cofactors for **DNA synthesis** [3]. Specifically, Vitamin B12 is required for the conversion of homocysteine to methionine, a process linked to the production of thymidine. A deficiency leads to impaired DNA replication while RNA synthesis and cytoplasmic maturation continue normally. This results in **nuclear-cytoplasmic asynchrony** [2], where the nucleus remains immature while the cell volume increases, leading to the formation of abnormally large red blood cells called **macro-ovalocytes** (MCV > 100 fL) [1]. In the bone marrow, this is characterized by **megaloblastic erythropoiesis** [2]. **Incorrect Options:** * **A. Aplastic anemia:** This is characterized by pancytopenia due to bone marrow failure (hypocellular marrow), not a specific maturation defect. * **B. Iron deficiency anemia:** This results in **microcytic hypochromic anemia** because iron is essential for heme synthesis; lack of iron leads to smaller cells with less hemoglobin. * **C. Anemia of chronic disease:** Typically presents as **normocytic normochromic** anemia (though it can become microcytic) [5], caused by iron sequestration due to increased hepcidin levels during inflammation. **High-Yield Clinical Pearls for NEET-PG:** * **Hypersegmented Neutrophils:** The earliest peripheral blood sign of megaloblastic anemia (defined as >5% of neutrophils having 5 or more lobes or a single neutrophil with 6 lobes) [4]. * **Neurological Symptoms:** Unlike folate deficiency, Vitamin B12 deficiency causes **Subacute Combined Degeneration (SCD)** of the spinal cord due to the accumulation of methylmalonic acid (MMA). * **Schilling Test:** Historically used to differentiate the cause of B12 deficiency (e.g., Pernicious anemia vs. malabsorption). * **Biochemical markers:** Both **Homocysteine** and **Methylmalonic acid (MMA)** levels are elevated in B12 deficiency. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 592-593. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 593-594. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 654-655. [4] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, p. 654. [5] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 594-595.

Question 806: Which one of the listed types of antibodies is the best example of a cold agglutinin associated with cold autoimmune hemolytic anemia?

A. An anti-AB IgM antibody associated with isoimmune blood transfusion reaction
B. An anti-I IgM antibody associated with infectious mononucleosis (Correct Answer)
C. An anti-I IgG antibody associated with rheumatoid arthritis
D. An anti-P IgG antibody associated with paroxysmal cold hemoglobinuria

Explanation: ### Explanation **1. Why Option B is Correct:** Cold Autoimmune Hemolytic Anemia (cAIHA) is characterized by **IgM autoantibodies** that bind to the erythrocyte surface at low temperatures (optimally <4°C). These antibodies are typically directed against the **I antigen** on the red cell membrane. Upon binding, they fix complement (C3b). When the cells return to warmer central circulation, the IgM dissociates, but the C3b remains, leading to extravascular hemolysis in the liver. This condition is classically associated with **Infectious Mononucleosis** (EBV) and *Mycoplasma pneumoniae* infections. **2. Analysis of Incorrect Options:** * **Option A:** Anti-AB IgM antibodies are naturally occurring isoagglutinins. While they are IgM, they cause **acute intravascular hemolysis** during mismatched transfusions, not autoimmune cold agglutinin disease. * **Option B:** In 'warm antibody' immune haemolytic anaemia, the autoantibody is usually IgG and may or may not bind complement, with destruction occurring in the spleen [1]. * **Option D:** This describes **Paroxysmal Cold Hemoglobinuria (PCH)**. While triggered by cold, PCH is caused by the **Donath-Landsteiner antibody**, which is an **IgG** directed against the **P antigen**. It is a unique "biphasic" hemolysin. **3. NEET-PG High-Yield Pearls:** * **Cold Agglutinin Disease:** IgM + Anti-I specificity + Extravascular hemolysis (Liver). * **Warm AIHA:** IgG + Anti-Rh specificity + Extravascular hemolysis (Spleen) + Spherocytes [1]. * **PCH:** IgG + Anti-P specificity + Intravascular hemolysis. * **Peripheral Smear:** Look for **RBC clumping/agglutination** in cold AIHA, which disappears upon warming the slide. * **Direct Coombs Test:** In cold AIHA, the test is positive for **C3d** but negative for IgG. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 602-603.

Question 807: Most of the ALLs (Acute Lymphoblastic Leukemia) have which of the following origins?

A. B-cell origin (Correct Answer)
B. T-cell origin
C. NK cell origin
D. None of the above

Explanation: **Explanation:** Acute Lymphoblastic Leukemia (ALL) is a malignant neoplasm of hematopoietic precursor cells (lymphoblasts) of either B-cell or T-cell lineage [1]. **1. Why B-cell origin is correct:** The vast majority of ALL cases—approximately **80% to 85%**—are of **B-cell origin (B-ALL)** [1]. These typically manifest as childhood leukemias, with a peak incidence around 3 years of age. They are characterized by the expression of B-cell markers such as CD19, CD22, and CD10 (CALLA). The predominance of B-cell lineage in clinical practice makes it the most common subtype. **2. Why other options are incorrect:** * **T-cell origin:** T-cell ALL (T-ALL) accounts for only about **15% to 20%** of cases [1]. It typically presents in adolescent males as a mediastinal mass (thymic involvement) and is often associated with a high white blood cell count [1]. * **NK cell origin:** Mature NK-cell leukemias or precursor NK-cell neoplasms are extremely rare and do not constitute a significant percentage of ALL cases [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Most common childhood cancer:** ALL is the most common malignancy in children. * **Common ALL Antigen (CALLA):** Also known as **CD10**, it is a key marker for prognosis; CD10+ (Pre-B ALL) has a better prognosis than CD10- cases. * **Cytogenetics:** * **t(12;21):** Most common translocation in childhood B-ALL; carries a **good prognosis**. * **t(9;22):** Philadelphia chromosome; more common in adult B-ALL; carries a **poor prognosis**. * **Sanctuary Sites:** ALL has a predilection for the **CNS and Testes**, requiring specific prophylactic therapy. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of White Blood Cells, Lymph Nodes, Spleen, and Thymus, pp. 596-600.

Question 808: Lymphocytosis is seen in which type of infections?

A. Fungal infections
B. Viral infections (Correct Answer)
C. Bacterial infections
D. Protozoal infections

Explanation: **Explanation:** **Lymphocytosis** refers to an absolute increase in the lymphocyte count (typically >4,000/µL in adults). This is a hallmark of the body's adaptive immune response to intracellular pathogens [1]. **Why Viral Infections are Correct:** Viruses are obligate intracellular pathogens. The primary defense mechanism against viral-infected cells involves **T-lymphocytes** (specifically CD8+ Cytotoxic T-cells) and **Natural Killer (NK) cells** [2]. During an acute viral infection, the body stimulates the proliferation of these cells to identify and destroy host cells harboring the virus. A classic example is Infectious Mononucleosis (EBV), which presents with "atypical lymphocytes" (Downey cells) [3]. **Why Other Options are Incorrect:** * **Bacterial Infections:** Typically cause **Neutrophilia** (increase in neutrophils) due to the acute inflammatory response and "left shift" (immature forms) [1], [4]. *Exceptions:* Pertussis, TB, and Brucellosis can cause lymphocytosis [1]. * **Fungal Infections:** Usually trigger a **granulomatous** response or chronic inflammation, often associated with monocytes and macrophages rather than a primary peripheral lymphocytosis [5]. * **Protozoal Infections:** Often lead to **Eosinophilia** (especially in helminthic/parasitic infestations) or monocytosis [4]. **NEET-PG High-Yield Pearls:** 1. **Bordetella pertussis:** A high-yield exception where a *bacterial* infection causes profound lymphocytosis (due to lymphocytosis-promoting factor preventing lymphocytes from entering lymph nodes) [1]. 2. **Atypical Lymphocytes:** Large, irregular cells with abundant cytoplasm "hugging" adjacent RBCs; seen in EBV, CMV, and Toxoplasmosis [3]. 3. **Chronic Lymphocytic Leukemia (CLL):** The most common cause of persistent, extreme lymphocytosis in elderly patients (often >100,000/µL). **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 195-196. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Infectious Diseases, pp. 360-362. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Infectious Diseases, pp. 369-370. [4] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of White Blood Cells, Lymph Nodes, Spleen, and Thymus, p. 592. [5] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Infectious Diseases, p. 360.

Question 809: All of the following are associated with Secondary Hemochromatosis except?

A. Thalassemia Major
B. Sideroblastic Anemia
C. Hereditary Spherocytosis
D. Paroxysmal Nocturnal Haemoglobinuria (PNH) (Correct Answer)

Explanation: **Explanation:** Secondary Hemochromatosis (acquired iron overload) occurs when the body’s iron stores exceed physiological limits due to external intake or ineffective erythropoiesis. **Why PNH is the Correct Answer:** In **Paroxysmal Nocturnal Hemoglobinuria (PNH)**, iron is actually **lost** from the body rather than accumulated [1]. Because PNH involves chronic intravascular hemolysis, hemoglobin is released into the plasma, filtered by the glomeruli, and reabsorbed by renal tubular cells [2]. These cells are eventually sloughed into the urine (hemosiderinuria), leading to a state of **iron deficiency** rather than overload [1]. **Analysis of Incorrect Options:** * **Thalassemia Major:** This is a classic cause of secondary hemochromatosis due to two factors: (1) repeated blood transfusions and (2) increased intestinal iron absorption triggered by "ineffective erythropoiesis" and low hepcidin levels [3]. * **Sideroblastic Anemia:** Characterized by impaired heme synthesis and ineffective erythropoiesis, leading to increased iron absorption and systemic deposition. * **Hereditary Spherocytosis:** While primarily an extravascular hemolytic anemia, chronic hemolysis and the potential need for multiple transfusions in severe cases can lead to secondary iron overload. **NEET-PG High-Yield Pearls:** * **Mechanism:** Secondary hemochromatosis is driven by **suppression of Hepcidin** (via Erythroferrone) due to massive erythroid hyperplasia. * **PNH Triad:** Hemolytic anemia, pancytopenia, and venous thrombosis [1]. * **Diagnosis of Iron Overload:** Serum ferritin >1000 ng/mL or liver biopsy showing iron index >1.9. * **Key Distinction:** Intravascular hemolysis (PNH) = Iron Loss; Ineffective Erythropoiesis (Thalassemia) = Iron Overload [1], [3]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 650-651. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 639-640. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, p. 648.

Question 810: Which of the following is not a finding in classical hemophilia (hemophilia A)?

A. Bleeding into soft tissues, muscles, and joints
B. Decreased factor VIII
C. Increased Prothrombin Time (Correct Answer)
D. Increased Partial Thromboplastin Time

Explanation: ### Explanation **Core Concept:** Hemophilia A is an X-linked recessive bleeding disorder caused by a deficiency or dysfunction of **Factor VIII** [2]. Factor VIII is a crucial component of the **intrinsic pathway** of the coagulation cascade. **Why "Increased Prothrombin Time" is the Correct Answer:** * **Prothrombin Time (PT)** measures the integrity of the **extrinsic and common pathways** (Factors VII, X, V, II, and I). * Since Hemophilia A only affects Factor VIII (intrinsic pathway), the PT remains **normal**. An increased PT would suggest deficiencies in the extrinsic pathway or Vitamin K-dependent factors. **Analysis of Incorrect Options:** * **A. Bleeding into soft tissues, muscles, and joints:** This is a hallmark clinical feature of secondary hemostasis defects (clotting factor deficiencies) [1]. **Hemarthrosis** (joint bleeding) is specifically characteristic of severe Hemophilia [1]. * **B. Decreased factor VIII:** This is the primary molecular defect in Hemophilia A [2]. * **D. Increased Partial Thromboplastin Time (aPTT):** The aPTT measures the **intrinsic and common pathways**. Because Factor VIII is deficient, the intrinsic pathway is impaired, leading to a **prolonged (increased) aPTT**. **High-Yield Clinical Pearls for NEET-PG:** * **Mixing Study:** In Hemophilia A, a prolonged aPTT will **correct** when mixed with normal plasma (distinguishes it from Factor VIII inhibitors/antibodies). * **Bleeding Time (BT):** Remains **normal** in Hemophilia because platelet function and primary hemostasis are unaffected. * **Inheritance:** X-linked recessive (mostly affects males; females are typically asymptomatic carriers) [2]. * **Treatment:** Recombinant Factor VIII concentrate or Cryoprecipitate (though the latter is less preferred due to infection risks) [1]. * **Differential:** Hemophilia B (Christmas Disease) is a deficiency of **Factor IX**; clinically indistinguishable from Hemophilia A without a specific factor assay. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 623-624. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 670-671.

Practice by Chapter

Anemias: Classification and Approach

Practice Questions

Hemolytic Anemias

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Myeloproliferative Neoplasms

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Myelodysplastic Syndromes

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Acute Leukemias

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Chronic Leukemias

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Lymphomas and Lymphoid Neoplasms

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Plasma Cell Disorders

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Bleeding Disorders

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Thrombotic Disorders

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