Hematopathology Practice Questions

Q: Prothrombin time is prolonged in all of the following conditions except:

Von Willebrand's disease. ***Von Willebrand's disease*** - **Von Willebrand's disease** primarily affects **platelet adhesion** and the **intrinsic coagulation pathway** (by carrying factor VIII), rather than the extrinsic pathway measured by PT [1]. - Patients typically have a **normal prothrombin time (PT)** and activated partial thromboplastin time (aPTT) that may be normal or slightly prolonged. *Liver disease* - The **liver** synthesizes most **coagulation factors**, including those measured by PT (factor VII from the extrinsic pathway and factors II, V, X from the common pathway) [3]. - Severe **liver disease** impairs factor synthesis, leading to **deficiencies** and a prolonged PT [1]. *Disseminated intravascular coagulation* - **DIC** involves widespread activation of the coagulation system, leading to the consumption of **clotting factors**, including those measured by PT [2]. - This **consumption coagulopathy** results in prolonged PT, aPTT, and thrombocytopenia [2]. *Warfarin therapy* - **Warfarin** is a **vitamin K antagonist** that inhibits the synthesis of vitamin K-dependent clotting factors (II, VII, IX, X) [1], [3]. - By inhibiting **factor VII** (extrinsic pathway) and the **common pathway factors**, warfarin prolongs the **prothrombin time (PT)**, which is used to monitor its anticoagulant effect [3]. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 624-625. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 625-626. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 582-583.

Q: Which immunohistochemistry marker is associated with histiocytosis X?

CD1a. ***CD1a*** - **CD1a** is a key immunohistochemical marker for **Langerhans cells**, which are the principal cells involved in **Histiocytosis X** (Langerhans Cell Histiocytosis) [1]. - The presence of **CD1a** helps differentiate Langerhans cell lesions from other histiocytic lesions and is essential for the diagnosis [1]. *CD3* - **CD3** is predominantly a marker for **T lymphocytes**, not associated with histiocytosis or Langerhans cells. - Its presence indicates **T-cell** activation, not histiocytic processes. *CD68* - **CD68** is a marker for **macrophages** and tissue histiocytes but is not specific for Langerhans cells or Histiocytosis X. - While it can be present in various histiocytic conditions, it does not specifically identify Histiocytosis X. *CD57* - **CD57** is typically associated with certain **natural killer (NK) cells** and some **T-cell** subsets, not with histiocytes. - Its presence does not indicate involvement in histiocytic proliferative disorders. **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, p. 630.

Q: Which antibody is primarily involved in warm antibody autoimmune hemolytic anemia?

IgG. ***IgG*** - **Warm antibody autoimmune hemolytic anemia (wAIHA)** is predominantly mediated by **IgG antibodies** [1]. - These IgG antibodies bind optimally at **37°C (body temperature)**, leading to extravascular hemolysis (primarily in the spleen) [1]. *IgM* - **IgM antibodies** are primarily involved in **cold agglutinin disease**, a type of cold autoimmune hemolytic anemia. - They bind optimally at **lower temperatures (below 37°C)** and often cause intravascular hemolysis. *IgE* - **IgE antibodies** are primarily associated with **allergic reactions** and **parasitic infections**. - They do not play a significant role in the pathophysiology of autoimmune hemolytic anemias. *IgA* - While **IgA antibodies** can occasionally be found in some cases of AIHA, they are generally considered a **minor contributor** and not the primary antibody class in wAIHA. - Their presence often signifies a **mixed-type AIHA** rather than pure warm AIHA. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 602-603.

Q: Which of the following statements regarding hereditary spherocytosis is false?

Splenomegaly is not a feature of hereditary spherocytosis. ***Spherocytosis is a pathognomic finding*** - Spherocytosis is not **pathognomic** for hereditary spherocytosis as it can also occur in other conditions like autoimmune hemolytic anemia. - While **spherocytes** are a notable finding in hereditary spherocytosis, they are not exclusive to this disorder. *Anemia* - Anemia is a common result of **hemolysis** in hereditary spherocytosis due to the destruction of spherical red blood cells [1]. - Patients often present with **mild to moderate anemia** [1][2], but this is a characteristic finding, not an exception. *Splenomegaly* - Splenomegaly is frequently observed in hereditary spherocytosis due to **hypertrophy** from increased red blood cell destruction. - This finding is **typical** in cases of hereditary spherocytosis and serves as an important clinical indicator [2]. *It is due to intrinsic defect in RBC membrane skeleton* - Hereditary spherocytosis is primarily caused by an **intrinsic defect in the red blood cell membrane**, particularly affecting proteins like spectrin and ankyrin [1]. - This intrinsic defect leads to the formation of **spherocytes**, which are less deformable and prone to hemolysis [1][2]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 640-642. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 597-598.

Q: Which of the following statements about reticulocytes is correct?

Increased in hemolytic anemia. ***↑in hemolytic anemia*** - Reticulocyte count is typically **increased** in hemolytic anemia as the bone marrow responds to **acute blood loss** or increased hemolysis by producing more red blood cells [1]. - This reflects the body's mechanism to replace **lost RBCs**, making reticulocyte counts a useful marker in diagnosing anemia types. *Contain nucleus* - Reticulocytes do not contain a **nucleus**; they are immature red blood cells that have **already extruded** their nucleus. - Their main function is to mature into erythrocytes, which are **anucleate** cells. *Staining is done by Romanowsky stain* - Reticulocytes are typically stained using **methylene blue** or **brilliant cresyl blue**, not Romanowsky stain, which is used for **WBC and smears**. - These specific stains highlight the **reticulated cytoplasm**, indicating RNA presence, crucial for identifying reticulocytes. *Smaller than RBC* - Reticulocytes are generally **larger** than mature red blood cells (RBCs) due to their **cellular contents**, which are not fully extruded yet. - Their size is an important factor in distinguishing them from mature RBCs during evaluation. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 638-639.

Q: A 9-year-old boy with elevation in both prothrombin time (PT) and activated partial thromboplastin time (APTT) is diagnosed with what?

Defect in common pathway. ***Defect in common pathway*** - Elevation in both **prothrombin time (PT)** and **activated partial thromboplastin time (APTT)** indicates a problem in the **common pathway**, affecting factors I, II, V, X [1]. - This defect can result from conditions such as **vitamin K deficiency** or **liver dysfunction**, which impact multiple coagulation factors. *Platelet function defect* - Typically presents with **prolonged bleeding times** but does not affect PT or APTT, which remain normal. - Symptoms often include **petechiae** or **easy bruising**, rather than the coagulation profile observed here. *Defect in extrinsic pathway* - Primarily affects **PT** only, not APTT, as this pathway involves factors VII and tissue factor [1]. - Conditions like **vitamin K deficiency** can cause prolonged PT, but APTT would not be elevated simultaneously in isolation. *Defect in intrinsic pathway* - Affects **APTT** primarily, causing a prolonged APTT while PT remains normal [1]. - Common conditions include **Hemophilia A or B**, but the simultaneous elevation of both PT and APTT rules this out. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Hemodynamic Disorders, Thromboembolic Disease, and Shock, pp. 128-130.

Q: Maximum erythrocyte sedimentation rate (ESR) is seen in:

Multiple myeloma. ***Multiple myeloma*** - In **multiple myeloma**, the presence of an abundance of abnormal **monoclonal paraproteins** (immunoglobulins) in the blood significantly reduces the zeta potential of red blood cells [1]. - This reduction in electrostatic repulsion causes red blood cells to **aggregate much faster**, leading to a dramatic increase in **ESR** [1]. *Polycythemia vera* - **Polycythemia vera** is characterized by an overproduction of red blood cells, increasing **blood viscosity**. - A higher red blood cell count causes increased collisions and slower aggregation, leading to a **reduced** or normal ESR. *Sickle cell anemia* - In **sickle cell anemia**, the abnormally shaped **sickle cells** do not rouleaux well (stack up like coins) [2]. - This inhibits the normal sedimentation process, often resulting in a **decreased** or normal ESR despite inflammation [2]. *Congestive heart failure (CHF)* - While **CHF** can be associated with some inflammatory markers and a mildly elevated ESR, it does not typically cause the **extremely high ESR values** seen in conditions like multiple myeloma. - The elevation is usually moderate and related to the inflammatory state associated with the disease, not direct effects on red blood cell aggregation.

Question 1

Prothrombin time is prolonged in all of the following conditions except:

Accepted Answer

Von Willebrand's disease

Answer

Liver disease

Answer

Disseminated intravascular coagulation

Answer

Warfarin therapy

Question 2

Which immunohistochemistry marker is associated with histiocytosis X?

Accepted Answer

CD1a

Answer

CD57

Answer

CD3

Answer

CD68

Question 3

Which antibody is primarily involved in warm antibody autoimmune hemolytic anemia?

Accepted Answer

IgG

Answer

IgM

Answer

IgE

Answer

IgA

Question 4

Which of the following statements regarding hereditary spherocytosis is false?

Accepted Answer

Splenomegaly is not a feature of hereditary spherocytosis

Answer

Anemia

Answer

It is due to intrinsic defect in RBC membrane skeleton

Answer

Spherocytes are the characteristic finding on peripheral blood smear

Question 5

Which of the following statements about reticulocytes is correct?

Accepted Answer

Increased in hemolytic anemia

Answer

Larger than RBC

Answer

Contain nucleus

Answer

Staining is done by Romanowsky stains

Question 6

A 9-year-old boy with elevation in both prothrombin time (PT) and activated partial thromboplastin time (APTT) is diagnosed with what?

Accepted Answer

Defect in common pathway

Answer

Platelet function defect

Answer

Defect in the extrinsic pathway

Answer

Defect in the intrinsic pathway

Question 7

Maximum erythrocyte sedimentation rate (ESR) is seen in:

Accepted Answer

Multiple myeloma

Answer

Polycythemia vera

Answer

Sickle cell anemia

Answer

Congestive heart failure (CHF)

Question 8

Which of the following is a characteristic finding in hereditary spherocytosis?

Accepted Answer

Increased Osmotic Fragility

Answer

Increased Reticulocyte Count

Answer

Splenomegaly

Answer

Negative Direct Coombs Test

Hematopathology — MCQs

Hematopathology — MCQs

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