Hematopathology — MCQs

A 42-year-old man sustained severe injuries in an automobile accident and is admitted to the intensive care unit. Examination of a peripheral blood smear on the 3rd day of admission reveals helmet cells, schistocytes, and decreased platelets. Which of the following is most strongly suggested by these findings?

Hematopathology Indian Medical PG Practice Questions and MCQs

Question 551: What is the most specific investigation in disseminated intravascular coagulation?

A. D-dimer assay (Correct Answer)
B. Bleeding time
C. Clotting time
D. Fibrinogen level

Explanation: ### Explanation **Disseminated Intravascular Coagulation (DIC)** is a complex thrombo-hemorrhagic disorder characterized by the systemic activation of coagulation, leading to the formation of microthrombi and the subsequent consumption of platelets and clotting factors [1]. **Why D-dimer is the Correct Answer:** D-dimer is a specific degradation product of **cross-linked fibrin**. In DIC, the simultaneous activation of the coagulation cascade (forming fibrin clots) and the fibrinolytic system (plasmin breaking down those clots) occurs [2]. The presence of D-dimer indicates that not only has fibrin been formed, but it has also been cross-linked by Factor XIII and subsequently lysed by plasmin [2]. This makes it the **most specific** indicator of active fibrinolysis following intravascular coagulation. **Analysis of Incorrect Options:** * **Bleeding Time (BT):** Reflects platelet function and number. While BT is prolonged in DIC due to thrombocytopenia, it is non-specific and seen in various other platelet disorders [1]. * **Clotting Time (CT):** A crude measure of the intrinsic pathway. While prolonged in DIC, it lacks the sensitivity and specificity required for diagnosis. * **Fibrinogen Level:** Fibrinogen is an acute-phase reactant. While low levels are suggestive of DIC (due to consumption), a "normal" level may actually be a relative decrease in a sick patient. It is **sensitive but not specific**, as low levels can also occur in liver disease or congenital afibrinogenemia. **High-Yield Clinical Pearls for NEET-PG:** * **Best Screening Test:** Platelet count (usually decreased). * **Most Sensitive Test:** FDP (Fibrin Degradation Products), but it is less specific than D-dimer because FDPs also rise during the breakdown of fibrinogen (primary fibrinolysis) [1]. * **Peripheral Smear Finding:** **Schistocytes** (fragmented RBCs) due to microangiopathic hemolytic anemia (MAHA). * **PT and aPTT:** Both are typically prolonged due to the consumption of coagulation factors. **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. 151-152. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Hemodynamic Disorders, Thromboembolic Disease, and Shock, pp. 130-132.

Question 552: Which of the following is NOT a cause of congenital hypercoagulability?

A. Protein C deficiency
B. Protein S deficiency
C. Antiphospholipid antibody syndrome (Correct Answer)
D. MTHFR gene mutations

Explanation: **Explanation:** The core concept in this question is distinguishing between **inherited (congenital)** and **acquired** causes of thrombophilia [3]. **Why Antiphospholipid Antibody Syndrome (APS) is the correct answer:** APS is an **acquired** autoimmune hypercoagulable state [1]. It is characterized by the presence of clinical symptoms (venous/arterial thrombosis or pregnancy complications) and laboratory evidence of antibodies (Lupus anticoagulant, Anti-cardiolipin, or Anti-̢2 glycoprotein I) [1], [2]. Unlike the other options, it is not a genetic defect passed down through germline mutations but rather a condition that develops during an individual's lifetime. **Analysis of Incorrect Options (Congenital Causes):** * **Protein C and S Deficiencies:** These are autosomal dominant inherited conditions. Protein C and S are natural anticoagulants that inactivate Factors Va and VIIIa [3]. Their deficiency leads to an inability to regulate the coagulation cascade, causing a lifelong risk of thrombosis. * **MTHFR Gene Mutations:** Mutations in the Methylenetetrahydrofolate Reductase (MTHFR) gene are inherited. They can lead to hyperhomocysteinemia, which damages endothelial cells and promotes a prothrombotic state. **NEET-PG High-Yield Pearls:** * **Most common inherited cause of hypercoagulability:** Factor V Leiden mutation (resistance to Activated Protein C) [3]. * **Most common acquired cause of hypercoagulability:** Surgery/Immobilization; however, among autoimmune causes, **APS** is the most significant [1]. * **Warfarin-induced skin necrosis:** Classically associated with **Protein C deficiency** due to the short half-life of Protein C compared to other Vitamin K-dependent factors. * **APS Laboratory Paradox:** It causes a **prolonged aPTT** *in vitro* (due to interference with phospholipids in the test) but causes **thrombosis** *in vivo* [1], [2]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Hemodynamic Disorders, Thromboembolic Disease, and Shock, pp. 134-135. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 626-627. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Hemodynamic Disorders, Thromboembolic Disease, and Shock, pp. 133-134.

Question 553: Which of the following features cannot be used to differentiate between Hodgkin's lymphoma and Non-Hodgkin's lymphoma?

A. Extranodal involvement
B. Contiguous spread
C. Painless lymphadenopathy (Correct Answer)
D. Localization to a particular group of lymph nodes

Explanation: ### Explanation The correct answer is **C. Painless lymphadenopathy**. #### Why is this the correct answer? Both Hodgkin’s Lymphoma (HL) and Non-Hodgkin’s Lymphoma (NHL) typically present with **painless, firm, and rubbery lymphadenopathy**. Since this clinical feature is common to both conditions, it cannot be used as a distinguishing factor. In both cases, pain only usually occurs if the lymph node grows rapidly enough to stretch the capsule or if there is secondary infection/infarction. #### Why the other options are incorrect: * **Extranodal involvement (A):** This is a hallmark of **NHL**, where involvement of the GI tract, skin, or bone marrow is common at presentation [1]. In contrast, HL is primarily confined to the lymph nodes and rarely presents with extranodal disease (except in very advanced stages) [1]. * **Contiguous spread (B):** **HL** characteristically spreads in an orderly, predictable fashion to the next contiguous (adjacent) group of lymph nodes (e.g., cervical to supraclavicular) [1], [2]. **NHL** spread is non-contiguous, often skipping node groups and appearing in distant sites unpredictably [1], [2]. * **Localization (D):** **HL** is frequently localized to a single axial group of nodes (most commonly cervical, mediastinal, or axillary) [1], [2]. **NHL** is more likely to involve multiple peripheral nodes and Waldeyer’s ring [3]. --- ### High-Yield Clinical Pearls for NEET-PG: * **Alcohol-induced pain:** A rare but specific sign for **Hodgkin’s Lymphoma** is pain in the lymph nodes following alcohol consumption [2]. * **B-Symptoms:** Fever, night sweats, and weight loss are more common in HL and high-grade NHL [2]. * **Reed-Sternberg (RS) Cells:** The diagnostic hallmark of HL; they are "bystanders" in a background of reactive inflammatory cells [1]. In NHL, the malignant cells constitute the bulk of the tumor mass. * **Waldeyer’s Ring & Mesenteric Nodes:** Frequently involved in NHL, but rarely in HL. **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. 614-616. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 557-558. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 560-561.

Question 554: Which of the following is NOT part of the triad of hairy cell leukemia?

A. Splenomegaly
B. Pancytopenia
C. Erythema nodosum (Correct Answer)
D. Hypercellular marrow

Explanation: **Explanation:** Hairy Cell Leukemia (HCL) is a rare, chronic B-cell lymphoproliferative disorder characterized by the classic clinical triad of **Splenomegaly, Pancytopenia, and "Dry Tap" on bone marrow aspiration.** [1] 1. **Why Erythema Nodosum is correct:** Erythema nodosum is a form of panniculitis (inflammation of fat cells under the skin) associated with infections (Streptococcal, TB), Sarcoidosis, or Inflammatory Bowel Disease. It is **not** a feature of HCL. 2. **Why the other options are part of HCL:** * **Splenomegaly:** This is the most common physical finding (often massive) due to the infiltration of the red pulp by "hairy" cells [1]. Notably, lymphadenopathy is usually absent. * **Pancytopenia:** Resulting from bone marrow infiltration and splenic sequestration [1]. Monocytopenia is a highly specific hallmark of HCL. * **Hypercellular marrow (with fibrosis):** While the marrow is often hypercellular with a characteristic "fried egg" appearance (cells with abundant cytoplasm and distinct borders), the increased reticulin fibrosis leads to a **"Dry Tap"** during aspiration [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Morphology:** B-cells with hair-like cytoplasmic projections [1]. * **Cytochemistry:** **TRAP positive** (Tartrate-Resistant Acid Phosphatase). * **Immunophenotype:** Positive for **CD11c, CD25, CD103**, and CD123. * **Genetic Mutation:** **BRAF V600E** mutation is seen in almost all cases. * **Treatment:** Cladribine (2-CdA) is the drug of choice. * **Biopsy Finding:** "Fried egg" appearance in the bone marrow and "Beefy red" appearance of the spleen [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. 610-612.

Question 555: Which of the following are common features of hemolytic anemia?

A. Decreased RBC life span, Unconjugated hyperbilirubinemia, Bile salt and bile pigments in urine
B. Decreased RBC life span, Unconjugated hyperbilirubinemia, Altered erythroid and myeloid ratio (Correct Answer)
C. Unconjugated hyperbilirubinemia, Bile salt and bile pigments in urine, Altered erythroid and myeloid ratio
D. Decreased RBC life span, Bile salt and bile pigments in urine, Altered erythroid and myeloid ratio

Explanation: Hemolytic anemia is characterized by the premature destruction of red blood cells (RBCs). The correct answer (Option B) reflects the three cardinal pathophysiological consequences of this process [1]: 1. **Decreased RBC Life Span:** By definition, hemolysis involves the destruction of RBCs before their normal 120-day lifespan [2]. 2. **Unconjugated Hyperbilirubinemia:** When RBCs break down, hemoglobin is released and metabolized. The heme moiety is converted into unconjugated (indirect) bilirubin [1]. Since the liver's conjugating capacity is overwhelmed, levels of unconjugated bilirubin rise in the blood [1]. 3. **Altered Erythroid to Myeloid (E:M) Ratio:** To compensate for the loss of RBCs, the bone marrow undergoes **erythroid hyperplasia** [1]. The normal E:M ratio (typically 1:3 or 1:4) becomes reversed or altered (e.g., 1:1 or higher) as erythropoiesis increases [3]. **Why other options are incorrect:** Options A, C, and D are incorrect because they include **"Bile salts and bile pigments in urine."** In hemolytic anemia, the bilirubin is **unconjugated**, which is lipid-soluble and bound to albumin; therefore, it cannot be filtered by the glomerulus and **does not appear in the urine** (acholuric jaundice) [1]. Bile salts and pigments in urine are hallmarks of **obstructive (surgical) jaundice**, not hemolytic anemia. **NEET-PG High-Yield Pearls:** * **Acholuric Jaundice:** Hemolytic anemia is characterized by jaundice without bilirubinuria [4]. * **Reticulocytosis:** An elevated reticulocyte count is the most common peripheral blood finding indicating a compensatory marrow response [1]. * **Haptoglobin:** In intravascular hemolysis, serum haptoglobin levels decrease as it binds to free hemoglobin [4]. * **Urobilinogen:** While bilirubin is absent in urine, **urinary urobilinogen** is typically increased in hemolytic states [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, p. 640. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 596-597. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 644-645. [4] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 639-640.

Question 556: Which of the following is a cold agglutinin?

A. IgG antibody
B. IgM antibody (Correct Answer)
C. Donath-Landsteiner antibody
D. IgA antibody

Explanation: Cold agglutinins are autoantibodies that optimally bind to the surface of red blood cells (RBCs) at low temperatures (typically $0-4^\circ\text{C}$). **Why IgM is the correct answer:** The majority of Cold Agglutinin Disease (CAD) is mediated by **IgM antibodies**. Due to its large pentameric structure, IgM has high avidity and can easily bridge the distance between RBCs, causing visible agglutination even with low thermal amplitude [1]. These antibodies are usually directed against the **I/i antigen** system on the RBC membrane. Once the blood warms up in the central circulation, the IgM dissociates, but it often leaves behind **C3b complement** components on the RBC surface, leading to extravascular hemolysis in the spleen. **Analysis of Incorrect Options:** * **IgG antibody:** These are typically **Warm Agglutinins**, reacting best at $37^\circ\text{C}$. They are monomeric and usually cause extravascular hemolysis via Fc-receptor-mediated phagocytosis in the spleen. * **Donath-Landsteiner antibody:** This is a unique **IgG** antibody (not IgM) associated with Paroxysmal Cold Hemoglobinuria (PCH). It is a biphasic hemolysin that binds at cold temperatures but fixes complement and causes hemolysis only upon warming to $37^\circ\text{C}$. * **IgA antibody:** While IgA can rarely cause autoimmune hemolytic anemia, it is not classified as a classic cold agglutinin. **High-Yield Clinical Pearls for NEET-PG:** * **Associations:** Acute cold agglutinin titers rise following **Mycoplasma pneumoniae** (anti-I) and **Infectious Mononucleosis/EBV** (anti-i). * **Blood Smear:** Characterized by **RBC clumps/agglutination** (unlike Rouleaux, these are irregular clusters). * **Lab Artifact:** Can cause a falsely elevated Mean Corpuscular Volume (MCV) and falsely low RBC count on automated analyzers. * **Coombs Test:** Direct Antiglobulin Test (DAT) is typically positive for **C3d** only (IgM dissociates and is not detected). **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. 154-155.

Question 557: Osmotic fragility is increased in which of the following conditions?

A. Sickle cell anemia
B. Hereditary spherocytosis (Correct Answer)
C. Thalassaemia
D. Chronic lead poisoning

Explanation: ### Explanation **Correct Answer: B. Hereditary Spherocytosis** **Underlying Concept:** Osmotic Fragility (OF) measures the resistance of red blood cells (RBCs) to hemolysis when exposed to varying concentrations of hypotonic saline [1]. The primary determinant of OF is the **surface area-to-volume (SA:V) ratio**. In **Hereditary Spherocytosis**, defects in membrane proteins (Ankyrin, Spectrin, or Band 3) lead to the loss of membrane fragments [2]. This results in the formation of **spherocytes**, which have the lowest possible SA:V ratio. Because they are already maximally "puffed up," they have no room to expand when water enters via osmosis, causing them to lyse at higher saline concentrations than normal cells. Thus, osmotic fragility is **increased** [1]. **Analysis of Incorrect Options:** * **A. Sickle cell anemia & C. Thalassaemia:** These conditions are characterized by **Target Cells** (codocytes). Target cells have an excess of membrane relative to hemoglobin (increased SA:V ratio). They can accommodate more water before bursting, leading to **decreased** osmotic fragility. * **D. Chronic lead poisoning:** This typically results in a sideroblastic or microcytic anemia with prominent **basophilic stippling**. It does not typically increase osmotic fragility; if anything, microcytosis may slightly decrease it. **High-Yield Clinical Pearls for NEET-PG:** * **Incubated Osmotic Fragility Test:** The sensitivity of the OF test is increased by incubating blood at 37°C for 24 hours, which further stresses the defective spherocyte membrane. * **Gold Standard Test:** While OF is a classic test, the **Eosin-5-maleimide (EMA) binding test** (via flow cytometry) is now the preferred diagnostic tool for Hereditary Spherocytosis. * **Splenectomy:** This is the definitive treatment to prevent hemolysis, as the spleen is the primary site where these fragile spherocytes are destroyed [1]. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 597-598. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 640-641.

Question 558: Castleman's disease is associated with which of the following?

A. Necrotizing vasculitis
B. Benign lymphoid hyperplasia (Correct Answer)
C. Necrotizing lymphadenitis
D. Coagulation defect

Explanation: **Explanation:** **Castleman’s Disease (CD)**, also known as **Angiofollicular Lymph Node Hyperplasia**, is a rare, non-clonal lymphoproliferative disorder. It is characterized by the **benign hyperplasia of lymphoid tissue**, often presenting as localized or systemic lymphadenopathy. 1. **Why Option B is correct:** Castleman’s disease is fundamentally a reactive, **benign lymphoid hyperplasia**. It is categorized into two main histological types: * **Hyaline-Vascular type (80-90%):** Characterized by "Lollipop follicles" (atrophic germinal centers with penetrating "candy-cane" vessels) and "Onion-skinning" of the mantle zone. * **Plasma Cell type:** Characterized by sheets of plasma cells and systemic symptoms (fever, anemia) driven by **Interleukin-6 (IL-6)**. 2. **Why other options are incorrect:** * **Option A (Necrotizing vasculitis):** This involves inflammation and destruction of blood vessel walls (e.g., Polyarteritis Nodosa). While CD has prominent vascularity, it does not involve necrotizing inflammation of the vessels. * **Option C (Necrotizing lymphadenitis):** This is the hallmark of **Kikuchi-Fujimoto disease**, characterized by focal paracortical necrosis with karyorrhectic debris, not the follicular hyperplasia seen in CD. * **Option D (Coagulation defect):** CD is not primarily associated with clotting factor deficiencies, though chronic inflammation may lead to secondary anemia or thrombocytosis. **High-Yield Clinical Pearls for NEET-PG:** * **Key Cytokine:** **IL-6** is the central driver of the systemic manifestations in the Plasma Cell and Multicentric variants. * **Viral Association:** Multicentric Castleman Disease (MCD) is strongly associated with **HHV-8** (Human Herpesvirus 8), especially in HIV-positive patients. * **POEMS Syndrome:** Castleman’s disease is a known component/association of POEMS syndrome (Polyneuropathy, Organomegaly, Endocrinopathy, M-protein, Skin changes). * **Microscopic Sign:** Look for the **"Lollipop lesion"** (sclerotic vessel entering an atrophic germinal center).

Question 559: A normotensive patient with normal hemoglobin suffered massive blood loss. The following findings could be expected, except:

A. Increased PCV (Correct Answer)
B. Increased MCV
C. Thrombocytosis
D. Reticulocytosis

Explanation: **Explanation:** In the setting of **acute massive blood loss**, the body loses whole blood (both cells and plasma) in equal proportions [3]. Therefore, the initial **Packed Cell Volume (PCV)** or Hematocrit remains unchanged. As the body compensates by shifting interstitial fluid into the vascular compartment to restore volume (hemodilution), the PCV actually **decreases**, not increases. Thus, "Increased PCV" is the correct "except" choice. **Analysis of other options:** * **Increased MCV:** Following significant hemorrhage, the bone marrow responds by releasing immature red cells (reticulocytes). Reticulocytes are larger than mature RBCs; a significant rise in their count can lead to a transient increase in the Mean Corpuscular Volume (MCV), known as **macrocytic stress reticulocytosis**. * **Thrombocytosis:** Acute blood loss triggers an immediate "stress response." Epinephrine-mediated splenic contraction and increased bone marrow activity lead to a reactive rise in platelet count (thrombocytosis) within hours [2]. * **Reticulocytosis:** This is the hallmark of the marrow's regenerative response to blood loss. It typically peaks 7–10 days after the acute event as the body attempts to replace lost erythrocytes [1]. **NEET-PG High-Yield Pearls:** * **Immediate Phase:** In the first few hours of acute hemorrhage, Hb and PCV are **unreliable** markers of the severity of blood loss because the ratio of cells to plasma hasn't changed yet. * **Leukocytosis:** Acute blood loss often causes a transient increase in WBC count (neutrophilia) due to demargination. * **Morphology:** The anemia of acute blood loss is initially **normocytic normochromic** [4]. It only becomes microcytic if chronic bleeding leads to iron deficiency. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, p. 638. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 590-591. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 638-639. [4] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 587-588.

Question 560: A 42-year-old man sustained severe injuries in an automobile accident and is admitted to the intensive care unit. Examination of a peripheral blood smear on the 3rd day of admission reveals helmet cells, schistocytes, and decreased platelets. Which of the following is most strongly suggested by these findings?

A. Autoimmune hemolysis
B. Disseminated intravascular coagulation (DIC) (Correct Answer)
C. Hereditary spherocytosis
D. Megaloblastic anemia

Explanation: ### Explanation The peripheral blood smear findings of **helmet cells** and **schistocytes** (fragmented red blood cells) are hallmarks of **Microangiopathic Hemolytic Anemia (MAHA)**. In this clinical scenario—a trauma patient in the ICU—the combination of MAHA and **thrombocytopenia** (decreased platelets) strongly points toward **Disseminated Intravascular Coagulation (DIC)** [1]. **Why DIC is correct:** DIC is a systemic process characterized by the widespread activation of the coagulation cascade, often triggered by severe trauma or sepsis [3]. This leads to the formation of microthrombi (fibrin strands) within small vessels. As RBCs pass through these narrowed lumens, they are mechanically sheared by the fibrin strands, resulting in schistocytes and helmet cells [4]. Platelets are consumed during the formation of these thrombi, leading to thrombocytopenia. **Why the other options are incorrect:** * **Autoimmune hemolysis:** Typically presents with **spherocytes** (due to splenic macrophages biting off portions of the antibody-coated membrane), not fragmented cells. The Direct Coombs test would be positive. * **Hereditary spherocytosis:** Characterized by an inherited defect in RBC membrane proteins (e.g., ankyrin, spectrin), leading to **spherocytes** and an increased MCHC, not schistocytes. * **Megaloblastic anemia:** Presents with **macro-ovalocytes** and **hypersegmented neutrophils** due to Vitamin B12 or Folate deficiency, not mechanical fragmentation. **NEET-PG High-Yield Pearls:** * **Schistocytes** = Mechanical trauma to RBCs. Think "MAHA" (DIC, HUS, or TTP) or prosthetic heart valves [2]. * **DIC Lab Profile:** Prolonged PT/aPTT, decreased Fibrinogen, and **elevated D-dimer** (most sensitive marker) [1]. * **Common DIC Triggers:** Sepsis (Gram-negative), Trauma, Obstetric complications (Abruptio placentae), and Acute Promyelocytic Leukemia (M3) [3]. **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. 151-152. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 667-668. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 671-673. [4] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 625-626.

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Anemias: Classification and Approach

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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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