Thalassemias — MCQs

10 questions

A child presents with recurrent chest infections and abdominal pain. There is a history of 1 blood transfusion in the past. On examination, he had icterus and mild splenomegaly. Electrophoresis shows increased HbA2, HbF, and S spike. What is the likely diagnosis?

Massive blood transfusion complications include all except -

Which of the following conditions is caused by the deletion of all four alpha globin genes?

Which of the following chelating agents is indicated in iron overdose?

A patient has MCV <80, MCH <23. Which type of anaemia shall be classified?

Diagnosis of beta thalassemia is established by what?

Which of the following are secondary iron overload conditions? I. Transfusion related iron load II. Thalassemia III. Hepatitis C associated liver disease Select the correct answer using the code given below :

Thalassemia gives protection against ?

Chronic hemolytic anaemia is associated with which of the following -

Q10

A patient is a known case of thalassemia. Which of the following viruses would be responsible for attacking progenitor cells and causing aplastic anemia?

Thalassemias Indian Medical PG Practice Questions and MCQs

Question 1: A child presents with recurrent chest infections and abdominal pain. There is a history of 1 blood transfusion in the past. On examination, he had icterus and mild splenomegaly. Electrophoresis shows increased HbA2, HbF, and S spike. What is the likely diagnosis?

A. HbC disease
B. Sickle cell disease
C. Aplastic anemia
D. Sickle Beta Thalassemia (Correct Answer)

Explanation: ***Sickle Beta Thalassemia*** - The combination of **sickle cell disease manifestations** (recurrent chest infections, abdominal pain, icterus, splenomegaly) with **electrophoresis showing increased HbA2, elevated HbF, and S spike** is diagnostic of **Sickle Beta Thalassemia**. - **Increased HbA2 (>3.5%)** is the key distinguishing feature that differentiates this from pure sickle cell disease. It indicates co-inheritance of a **beta-thalassemia gene** along with the **sickle cell gene**. - Clinical presentation is similar to sickle cell disease with **vaso-occlusive crises**, **acute chest syndrome**, hemolytic anemia, and organomegaly. - The severity depends on the type: S/β⁰-thalassemia (no HbA production) is clinically more severe and similar to SS disease, while S/β⁺-thalassemia (reduced HbA) tends to be milder. *Sickle cell disease* - Pure sickle cell disease (HbSS) presents with similar clinical features: recurrent chest infections, abdominal pain, hemolysis, and splenomegaly. - However, electrophoresis would show **normal or only slightly elevated HbA2 (2-3%)**, not the increased HbA2 mentioned in this case. - The presence of significantly increased HbA2 rules out pure sickle cell disease. *HbC disease* - Patients with HbC disease typically have **mild chronic hemolytic anemia** and **splenomegaly** but usually lack severe vaso-occlusive crises. - Electrophoresis would show primarily **HbC**, not an S spike. - The clinical picture is much milder than described in this case. *Aplastic anemia* - Characterized by **pancytopenia** due to bone marrow failure, leading to fatigue, infections, and bleeding tendency. - Does not involve hemolysis, icterus, or abnormal hemoglobin variants on electrophoresis. - The electrophoresis findings completely exclude this diagnosis.

Question 2: Massive blood transfusion complications include all except -

A. Hypothermia
B. Hyperkalemia
C. Hypernatremia (Correct Answer)
D. Hypocalcemia

Explanation: ***Hypernatremia*** - **Massive blood transfusions** typically involve transfusing red blood cells suspended in solutions like normal saline, which is **isotonic** or slightly hypotonic, or solutions containing **citrate**, which is metabolized in the liver to bicarbonate. - Therefore, hypernatremia is **not expected** and, in fact, hyponatremia can occur in some circumstances due to dilution or impaired sodium excretion in severely ill patients. *Hypothermia* - **Refrigerated blood products** are typically stored at 1-6°C; rapid infusion of large volumes of these cold products can significantly lower the patient's core body temperature, leading to **hypothermia**. - Hypothermia can worsen **coagulopathy** and cardiac arrhythmias, which are serious complications in critically ill or hemorrhaging patients. *Hyperkalemia* - As red blood cells are stored, there is a gradual leakage of **potassium** from intracellular to extracellular compartments due to reduced activity of the **Na+/K+ ATPase pump**. - During massive transfusion, the infusion of large volumes of blood with elevated extracellular potassium can lead to significant **hyperkalemia**, especially in patients with impaired renal function. *Hypocalcemia* - **Citrate** is an anticoagulant used in blood storage that binds to **ionized calcium** in the patient's blood, effectively chelating it. - Rapid infusion of large amounts of citrated blood can overwhelm the liver's capacity to metabolize citrate, leading to a significant drop in ionized calcium levels and consequently **hypocalcemia**.

Question 3: Which of the following conditions is caused by the deletion of all four alpha globin genes?

A. Beta thalassemia major
B. HbH
C. Hb Bart's (Correct Answer)
D. alpha thalassemia trait

Explanation: ***Hb Bart's*** - This condition, also known as **hydrops fetalis**, results from the **deletion of all four alpha globin genes**, leading to a complete absence of alpha globin chains [1]. - The excess gamma globin chains in the fetus form **tetramers (gamma4)**, which have a very high affinity for oxygen and do not release it to tissues, causing severe tissue hypoxia and usually intrauterine death [3]. *Beta thalassemia major* - This condition involves a reduced or absent production of **beta globin chains**, not alpha globin chains [2]. - It leads to an excess of **alpha globin chains**, which precipitate in red blood cells, causing severe anemia and ineffective erythropoiesis. *HbH* - This condition is caused by the **deletion of three out of four alpha globin genes**, leaving only one functional alpha globin gene [1], [2]. - The excess beta globin chains in adults form **tetramers (beta4)**, known as HbH, which are unstable and precipitate in red blood cells, leading to hemolytic anemia. *alpha thalassemia trait* - This refers to the deletion of **one or two alpha globin genes**, resulting in a mild reduction in alpha globin chain synthesis [1]. - Individuals with one gene deletion are often asymptomatic, while those with **two gene deletions** (alpha thalassemia minor) may have mild anemia with microcytosis but are generally asymptomatic [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. 649-650. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 600-601. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of Infancy and Childhood, pp. 470-472.

Question 4: Which of the following chelating agents is indicated in iron overdose?

A. Desferrioxamine (Correct Answer)
B. BAL
C. Calcium Edetate
D. DTPA
E. Penicillamine

Explanation: ***Desferrioxamine*** - **Desferrioxamine** is a **chelate** formed by the bacterium *Streptomyces pilosus* that has a high affinity for **iron**. - It is currently the most commonly used chelating agent for **acute iron overdose** and **chronic iron overload** conditions like hemochromatosis or transfusional hemosiderosis. *BAL* - **BAL (dimercaprol)** is a chelating agent primarily used for poisoning with **arsenic**, **mercury**, and **gold**. - It works by forming stable cyclic compounds with these metals, facilitating their excretion. *Calcium Edetate* - **Calcium edetate (Calcium-EDTA)** is primarily used for **lead poisoning**. - It works by forming a stable, water-soluble complex with lead, which is then excreted by the kidneys. *DTPA* - **Diethylenetriamine pentaacetate (DTPA)** is a chelating agent primarily used for poisoning with **plutonium** and other **radioactive metals**. - It is not indicated for iron overdose. *Penicillamine* - **Penicillamine** is a chelating agent primarily used for **copper** overload (Wilson's disease) and can also be used for **lead** and **mercury** poisoning. - It is not effective for iron chelation in overdose situations.

Question 5: A patient has MCV <80, MCH <23. Which type of anaemia shall be classified?

A. Microcytic hypochromic (Correct Answer)
B. Normocytic normochromic
C. Normocytic hypochromic
D. Hyperchromic macrocytic

Explanation: ***Microcytic hypochromic*** - A **Mean Corpuscular Volume (MCV)** less than **80 fL** indicates **microcytosis** (small red blood cells) [1]. - A **Mean Corpuscular Hemoglobin (MCH)** less than **23 pg** indicates **hypochromia** (pale red blood cells due to reduced hemoglobin content) [1]. *Normocytic normochromic* - This classification refers to red blood cells with **normal MCV (80-100 fL)** and **normal MCH (27-32 pg)**. - Examples include anemia of chronic disease or acute blood loss, which do not fit the given lab values. *Normocytic hypochromic* - While **hypochromia (MCH <23)** is present, the **MCV is less than 80 fL**, which makes it microcytic, not normocytic. - This combination is not a standard classification; hypochromia typically accompanies microcytosis [1]. *Hyperchromic macrocytic* - **Macrocytic anemia** is characterized by an **MCV >100 fL**, which is the opposite of the given MCV of <80. - The term "hyperchromic" is generally not used for anemia classification because red blood cells have a maximal hemoglobin concentration and cannot be truly hyperchromic. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 590-591.

Question 6: Diagnosis of beta thalassemia is established by what?

A. Hb electrophoresis (Correct Answer)
B. NESTROFT screening test
C. Hemoglobin A1c test
D. Presence of target cells in blood smear

Explanation: Hb electrophoresis - Hemoglobin electrophoresis directly measures the relative proportions of different hemoglobin types (HbA, HbA2, HbF), which is crucial for identifying the characteristic reduction in HbA and elevation of HbA2 and HbF in beta thalassemia. [1] - This method provides a definitive diagnostic profile by separating hemoglobin based on their electrical charge and size, allowing for quantification of abnormal hemoglobin variants. [1] *NESTROFT screening test* - The NESTROFT (Naked Eye Single Tube Red cell Osmotic Fragility Test) is a screening tool used to identify individuals with thalassemia traits and is not a definitive diagnostic test. - While useful for mass screening due to its simplicity and cost-effectiveness, it requires confirmation with more specific tests like hemoglobin electrophoresis. [1] *Hemoglobin A1c test* - The Hemoglobin A1c (HbA1c) test is primarily used to monitor long-term blood glucose control in individuals with diabetes. [2] - It measures the percentage of hemoglobin glycated over a period of 2-3 months and has no direct diagnostic utility for thalassemia. [2] *Presence of target cells in blood smear* - The presence of target cells in a blood smear is a non-specific finding that can be observed in various conditions, including iron deficiency anemia, liver disease, and other hemoglobinopathies, in addition to thalassemia. - While suggestive of a thalassemic disorder, it is not a conclusive diagnostic criterion and requires further investigation with specific diagnostic tests.

Question 7: Which of the following are secondary iron overload conditions? I. Transfusion related iron load II. Thalassemia III. Hepatitis C associated liver disease Select the correct answer using the code given below :

A. I and II only
B. I and III only
C. II and III only
D. I, II and III (Correct Answer)

Explanation: ***I, II and III*** - All three listed conditions—**transfusion-related iron load**, **thalassemia**, and **Hepatitis C associated liver disease**—are well-recognized causes of secondary iron overload. - Secondary iron overload occurs due to external factors or underlying diseases that cause increased iron absorption or repeated administration of iron. [1] *I and II only* - This option is incomplete as **Hepatitis C associated liver disease** can also lead to secondary iron overload due to impaired iron metabolism and chronic inflammation. - It dismisses a known cause of secondary iron accumulation. *I and III only* - This option is incomplete because **thalassemia**, particularly **transfusion-dependent thalassemia**, is a classic example of secondary iron overload due to frequent blood transfusions and ineffective erythropoiesis. - It overlooks a major cause of transfusion-related iron accumulation. [1] *II and III only* - This option is incomplete as **transfusion-related iron load** is a direct and common cause of secondary iron overload, especially in patients requiring regular blood transfusions for conditions like anemia. [1] - It ignores the most direct mechanism of iron accumulation in many chronic diseases.

Question 8: Thalassemia gives protection against ?

A. Protection against filaria
B. Protection against kala-azar
C. Protection against leptospirosis
D. Protection against malaria (Correct Answer)

Explanation: Protection against malaria - Individuals with thalassemia, particularly thalassemia trait, have some degree of protection against severe forms of malaria, specifically Plasmodium falciparum [1]. - The altered red blood cell structure and reduced hemoglobin content in thalassemia make the red blood cells less hospitable for the parasites, hindering their replication and survival [1]. Protection against filaria - Filaria is caused by parasitic worms (nematodes) transmitted by mosquitoes, leading to lymphatic filariasis (elephantiasis) or onchocerciasis (river blindness). - Thalassemia's primary impact is on red blood cell health and oxygen transport, offering no known protective effect against nematode infections or their associated pathology. Protection against kala-azar - Kala-azar (visceral leishmaniasis) is caused by Leishmania parasites transmitted by sandflies, primarily affecting the reticuloendothelial system (spleen, liver, bone marrow). - There is no established scientific evidence indicating that thalassemia provides protection against Leishmania infections or their clinical manifestations. Protection against leptospirosis - Leptospirosis is a bacterial infection caused by Leptospira bacteria, typically acquired through contact with contaminated water or animal urine. - Thalassemia is a genetic blood disorder; its physiological effects are unrelated to the mechanisms of infection or immunity against bacterial pathogens like Leptospira.

Question 9: Chronic hemolytic anaemia is associated with which of the following -

A. Brown Pigment stone of the gall bladder
B. Black Pigment stone of the gall bladder (Correct Answer)
C. Uric acid Renal Calculus
D. Intestinal Obstruction

Explanation: ***Black Pigment stone of the gall bladder*** - Chronic hemolytic anemia leads to increased **bilirubin**, particularly unconjugated bilirubin, which can result in the formation of **black pigment stones** [1]. - These stones are associated with conditions causing **excess bilirubin production**, such as sickle cell disease and thalassemia. *Brown Pigment stone of the gall bladder* - Brown pigment stones are primarily associated with **infection** and **biliary tract disorders**, not directly with chronic hemolytic anemia. - They are mainly composed of **calcium bilirubinate**, which arises in cases of **bacterial infections** or parasitic infestations. *Intestinal Obstruction* - While hemolytic anemia can have various complications, it is **not directly linked with intestinal obstruction**. - Obstruction typically arises from **mechanical causes** such as adhesions, tumors, or hernias, rather than from hemolytic processes. *Uric acid Renal Calculus* - Uric acid stones are formed due to conditions leading to **hyperuricemia** and are not a primary consequence of chronic hemolytic anemia. - They are often associated with **gout** and **certain metabolic disorders**, rather than hemolytic processes.

Question 10: A patient is a known case of thalassemia. Which of the following viruses would be responsible for attacking progenitor cells and causing aplastic anemia?

A. CMV (Cytomegalovirus)
B. EBV (Epstein-Barr Virus)
C. Parvovirus B19 (Correct Answer)
D. Hepatitis C virus (HCV)

Explanation: ***Parvovirus B19*** - **Parvovirus B19** specifically targets and replicates in **erythroid progenitor cells** in the bone marrow, leading to a temporary halt in red blood cell production [1]. - In patients with chronic hemolytic anemias like **thalassemia**, who already have increased erythropoietic demands, this can precipitate an **aplastic crisis** or pure red cell aplasia [1], [2]. *CMV (Cytomegalovirus)* - While CMV can affect the bone marrow and lead to myelosuppression, it does not typically cause a direct **aplastic crisis** by targeting erythroid progenitors in the same way as Parvovirus B19. - CMV often presents with a wider range of symptoms including fever, hepatitis, and mononucleosis-like syndrome, and bone marrow suppression is usually multi-lineage or less severe. *EBV (Epstein-Barr Virus)* - EBV is known to cause infectious mononucleosis and can also be associated with some bone marrow disorders, but it does not primarily target **erythroid progenitor cells** to cause an aplastic crisis. - Its main target cells are **B lymphocytes**, and any bone marrow suppression is often secondary to immune dysregulation rather than direct lytic infection of stem cells. *Hepatitis C virus (HCV)* - HCV infection can lead to various hematologic manifestations, including aplastic anemia, but these are typically **immune-mediated** or associated with chronic liver disease and its complications. - HCV does not directly infect and destroy **hematopoietic progenitor cells** in the bone marrow as a primary mechanism of aplastic anemia.

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