Disorders of Iron Metabolism — MCQs

10 questions

All of the following decrease in iron deficiency anemia except:

Iron metabolism and regulation are important for RBC precursor cells. Which of the following helps in the regulation of iron metabolism but is not specific for iron?

An adult female presents with pallor and fatigue. Blood investigations show low hemoglobin ( Hb ), low serum iron, low ferritin, low transferrin saturation, and increased total iron-binding capacity (TIBC). What is the likely diagnosis?

Which of the following is typically observed in the investigation results for a patient with iron deficiency anemia (IDA)?

What is the best treatment for anemia in patients with Chronic Renal Failure (CRF)?

Mr. Lallu, aged 54 years, who is a known diabetic patient, develops cirrhosis. There is associated skin hyperpigmentation and restrictive cardiomyopathy. Which of the following is the best initial test to diagnose this case?

A 65-year-old male presents with fatigue, pallor, and low hemoglobin. Which laboratory finding is most indicative of iron deficiency anemia?

All are increased in IDA except

Pappenheimer bodies are composed of:

Q10

Which of the following findings is diagnostic of iron deficiency anemia?

Disorders of Iron Metabolism Indian Medical PG Practice Questions and MCQs

Question 1: All of the following decrease in iron deficiency anemia except:

A. Serum iron
B. Ferritin
C. TIBC (Correct Answer)
D. Transferrin saturation

Explanation: ***TIBC*** - In **iron deficiency anemia**, the body attempts to maximize iron absorption and transport, leading to an **increase** in **Total Iron Binding Capacity (TIBC)** [1]. - TIBC reflects the amount of **transferrin** available to bind iron; more transferrin is produced when iron stores are low [1]. *Serum iron* - **Serum iron** measures the iron circulating in the blood bound to transferrin. - In **iron deficiency anemia**, the overall amount of circulating iron is **decreased** due to insufficient iron stores [1]. *Ferritin* - **Ferritin** is a storage protein for iron, reflecting the body's iron stores [2]. - In **iron deficiency anemia**, iron stores are depleted, resulting in a **decreased** serum ferritin level [1]. *Transferrin saturation* - **Transferrin saturation** is the percentage of transferrin binding sites occupied by iron. - In **iron deficiency anemia**, with low serum iron and increased TIBC, the percentage of binding sites occupied by iron is **lowered** [1].

Question 2: Iron metabolism and regulation are important for RBC precursor cells. Which of the following helps in the regulation of iron metabolism but is not specific for iron?

A. Hepcidin
B. DMT-1 (Correct Answer)
C. Ferroportin
D. Ferritin

Explanation: ***DMT-1*** - **DMT-1** (Divalent Metal Transporter 1) facilitates the transport of not only **iron** but also other divalent metals, making it essential for overall metal homeostasis. - It plays a role in the absorption of iron from the **intestine** and release from macrophages, influencing iron availability indirectly. *Hepcidin* - Hepcidin is a **specific** regulator of iron metabolism [2][4], controlling iron absorption and distribution but primarily for **iron regulation**. - It acts defensively against iron overload by inhibiting **ferroportin** [2], specifically targeting iron metabolism. *Ferritin* - Ferritin primarily serves as an **iron storage** protein [1], sequestering excess iron but not involved in its regulatory mechanism in the same context. - It indicates iron levels in the body but does not actively regulate iron metabolism. *Ferroportin* - Ferroportin is an **iron exporter** that helps in the release of iron from cells, particularly in macrophages and enterocytes [2][3], directly linked to iron metabolism regulation. - However, it is **specific for iron** and does not facilitate a broader regulation of other divalent metals. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, p. 658. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 658-659. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 657-658. [4] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Liver and Gallbladder, p. 854.

Question 3: An adult female presents with pallor and fatigue. Blood investigations show low hemoglobin ( Hb ), low serum iron, low ferritin, low transferrin saturation, and increased total iron-binding capacity (TIBC). What is the likely diagnosis?

A. Iron Deficiency Anemia (IDA) (Correct Answer)
B. Anemia of Chronic Disease
C. Hemolytic Anemia
D. Thalassemia
E. Sideroblastic Anemia

Explanation: ***Iron Deficiency Anemia (IDA)*** - The unique constellation of **low hemoglobin**, **low serum iron**, **low ferritin**, **low transferrin saturation**, and **increased total iron-binding capacity (TIBC)** is the hallmark of Iron Deficiency Anemia. - **Ferritin** is a direct measure of iron stores, and its low level confirms depletion, while **increased TIBC** signifies the body's attempt to absorb more iron due to deficiency. *Anemia of Chronic Disease* - While also presenting with **low hemoglobin** and often **low serum iron**, Anemia of Chronic Disease is characterized by **normal or increased ferritin** (as ferritin is an acute phase reactant) and **decreased TIBC**. - There is a functional iron deficiency, but iron stores are typically adequate, and inflammation plays a central role. *Hemolytic Anemia* - Hemolytic anemia is characterized by the premature destruction of red blood cells, leading to **low hemoglobin** but typically **normal or elevated serum iron** and ferritin due to iron release from lysed red cells. - Key indicators, such as **elevated bilirubin**, **lactate dehydrogenase (LDH)**, and **reticulocytosis**, are absent in the given scenario. *Thalassemia* - Thalassemia is a genetic disorder causing defective hemoglobin synthesis, resulting in **microcytic hypochromic anemia** with **low hemoglobin**. - However, thalassemia typically presents with **normal to high serum iron** and ferritin levels, as iron absorption may be increased, and there's no primary iron deficiency. *Sideroblastic Anemia* - Sideroblastic anemia is characterized by defective heme synthesis with iron accumulation in mitochondria, forming characteristic ring sideroblasts on bone marrow examination. - Laboratory findings typically show **normal to increased serum iron**, **increased ferritin**, and **increased transferrin saturation**, distinguishing it from iron deficiency anemia.

Question 4: Which of the following is typically observed in the investigation results for a patient with iron deficiency anemia (IDA)?

A. Increased serum ferritin
B. Decreased transferrin saturation (Correct Answer)
C. Increased serum iron
D. Normal total iron-binding capacity (TIBC)
E. Increased mean corpuscular volume (MCV)

Explanation: ***Decreased transferrin saturation*** - In **iron deficiency anemia**, there is insufficient iron to bind to **transferrin**, leading to a reduction in the percentage of transferrin that is iron-bound. - This reflects the body's struggle to supply iron for erythropoiesis due to depleted iron stores. *Increased serum ferritin* - **Serum ferritin** is a key indicator of the body's iron stores; in **iron deficiency anemia**, these stores are depleted, leading to a *decreased* rather than increased serum ferritin level. - An increased serum ferritin is typically seen in conditions of **iron overload** or **inflammation**. *Increased serum iron* - **Serum iron** measures the iron circulating in the blood, and in **iron deficiency anemia**, iron levels are *low* due to inadequate intake or excessive loss. - An increased serum iron level would contradict the diagnosis of iron deficiency. *Normal total iron-binding capacity (TIBC)* - **Total iron-binding capacity (TIBC)** typically *increases* in iron deficiency anemia as the liver produces more transferrin in an attempt to capture any available iron. - A normal TIBC would not reflect the compensatory mechanisms seen in iron deficiency. *Increased mean corpuscular volume (MCV)* - **Iron deficiency anemia** is a **microcytic anemia**, characterized by *decreased* MCV due to inadequate hemoglobin synthesis within red blood cells. - An increased MCV is seen in **macrocytic anemias** such as vitamin B12 or folate deficiency, not in iron deficiency.

Question 5: What is the best treatment for anemia in patients with Chronic Renal Failure (CRF)?

A. Oral Iron Therapy
B. Erythropoietin Stimulating Agents (Correct Answer)
C. Blood transfusion
D. Androgenic Steroids

Explanation: ***Erythropoietin Stimulating Agents*** - **Erythropoietin Stimulating Agents (ESAs)** are the cornerstone of anemia treatment in CRF because the primary cause of anemia in these patients is inadequate production of **endogenous erythropoietin** by the damaged kidneys [1]. - ESAs stimulate the bone marrow to produce red blood cells, effectively reversing the anemia and improving symptoms like fatigue and exercise intolerance [1]. *Oral Iron Therapy* - While **iron deficiency** often coexists with **anemia of chronic disease** in CRF patients, oral iron alone is usually insufficient to correct the anemia; it only addresses the iron component. - Many CRF patients have **functional iron deficiency** due to chronic inflammation, which impairs iron utilization, making oral iron less effective even with adequate stores. *Blood transfusion* - **Blood transfusions** provide a rapid increase in hemoglobin but are not the preferred long-term treatment for anemia in CRF due to risks of **iron overload**, **alloreactions**, and potential sensitization, which can complicate future transplantation. - Transfusions are typically reserved for acute, severe anemia or specific circumstances where ESAs are ineffective or contraindicated. *Androgenic Steroids* - **Androgenic steroids** can stimulate erythropoiesis, but their use is limited due to significant side effects such as **hepatotoxicity**, **virilization**, and **cardiac complications**, making them a less favorable option compared to ESAs. - They are considered a secondary or tertiary option, often in patients unresponsive to primary treatments or when other options are exhausted.

Question 6: Mr. Lallu, aged 54 years, who is a known diabetic patient, develops cirrhosis. There is associated skin hyperpigmentation and restrictive cardiomyopathy. Which of the following is the best initial test to diagnose this case?

A. Serum ceruloplasmin
B. Serum ferritin (Correct Answer)
C. Serum copper
D. Iron binding capacity

Explanation: ***Serum ferritin*** - Elevated **serum ferritin** is an excellent initial screening test for **hemochromatosis** due to its direct correlation with iron stores [1]. - The constellation of **cirrhosis**, **diabetes**, **skin hyperpigmentation**, and **restrictive cardiomyopathy** strongly points to hemochromatosis, a disorder of excessive iron accumulation [2]. *Serum ceruloplasmin* - This test is primarily used for diagnosing **Wilson's disease**, which involves copper accumulation, not iron. - While Wilson's can cause cirrhosis, the other symptoms (diabetes and skin hyperpigmentation) are not typical for this condition. *Serum copper* - **Serum copper** is another test for Wilson's disease or other copper metabolism disorders. - It does not directly assess iron stores and would not be the best initial test for suspected hemochromatosis. *Iron binding capacity* - **Total iron-binding capacity (TIBC)** measures the blood's capacity to bind iron, primarily reflecting transferrin levels. - While relevant to iron metabolism, **serum ferritin** is a more sensitive and specific initial screening test for diagnosing iron overload in hemochromatosis.

Question 7: A 65-year-old male presents with fatigue, pallor, and low hemoglobin. Which laboratory finding is most indicative of iron deficiency anemia?

A. Low ferritin level (Correct Answer)
B. High reticulocyte count
C. High TIBC
D. Normal MCV

Explanation: ***Low ferritin level*** - **Ferritin** is the primary storage protein for iron in the body, and its level is the most accurate indicator of the body's iron stores. - A **low ferritin level** directly reflects depleted iron stores, which is characteristic of iron deficiency anemia [2]. *High reticulocyte count* - A **high reticulocyte count** typically indicates that the bone marrow is actively producing red blood cells, which is usually a response to anemia, but not specifically diagnostic of iron deficiency. - In iron deficiency anemia, the bone marrow's ability to produce new red blood cells is impaired due to lack of iron, so the reticulocyte count might be normal or even low, not high. *High TIBC* - **Total iron-binding capacity (TIBC)** measures the blood's capacity to bind to iron and is usually high in iron deficiency anemia due to an increase in transferrin, which tries to capture any available iron [1]. - While a high TIBC is consistent with iron deficiency, a **low ferritin** is a more direct and reliable indicator of iron stores. *Normal MCV* - **Mean corpuscular volume (MCV)** measures the average size of red blood cells. In established iron deficiency anemia, MCV is typically low, indicating **microcytic anemia** [1]. - A normal MCV (normocytic anemia) can occur in the very early stages of iron deficiency or in other types of anemia, making it less specific for iron deficiency than ferritin levels.

Question 8: All are increased in IDA except

A. Transferrin saturation (Correct Answer)
B. TIBC
C. Soluble transferrin receptor
D. Erythropoietin

Explanation: ***Transferrin saturation*** - In **iron deficiency anemia (IDA)**, there is insufficient iron to saturate transferrin, leading to a **decreased** transferrin saturation. This is the exception among the given options. - Transferrin saturation is calculated as (serum iron / TIBC) x 100, and both **serum iron** and its percentage saturation are low in IDA. *TIBC* - **Total iron-binding capacity (TIBC)** is typically **increased** in IDA as the liver produces more transferrin in an attempt to capture more iron [1]. - This elevated TIBC reflects the body's compensatory mechanism to maximize available iron uptake. *Soluble transferrin receptor* - **Soluble transferrin receptor (sTfR)** levels are **elevated** in IDA because iron-deficient erythroblasts upregulate the production of transferrin receptors on their surface as they try to scavenge more iron. - The elevated sTfR is a sensitive and specific marker for **iron deficiency**, particularly useful in differentiating IDA from anemia of chronic disease [1]. *Erythropoietin* - **Erythropoietin (EPO)** levels are **increased** in IDA due to the kidney's response to the decreased oxygen-carrying capacity of the blood (anemia) [1]. - EPO stimulates the bone marrow to produce more red blood cells, which exacerbates the demand for iron, often leading to further iron depletion if iron stores are low.

Question 9: Pappenheimer bodies are composed of:

A. Copper
B. Iron (Correct Answer)
C. Lead
D. Zinc

Explanation: ***Iron*** - **Pappenheimer bodies** are composed of **iron granules** that have not been incorporated into hemoglobin. - They appear as small, irregular, basophilic inclusions within red blood cells on a **Wright-Giemsa stain**. *Copper* - **Copper** is an essential trace element but does not form these specific erythrocyte inclusions. - Its presence in excess can lead to conditions like **Wilson's disease**, affecting organs like the liver and brain. *Lead* - **Lead poisoning** can cause various red blood cell abnormalities, notably **basophilic stippling**, which represents aggregated ribosomes and not iron. - It interferes with heme synthesis, leading to **anemia**. *Zinc* - **Zinc** is a critical component of many enzymes, but it does not form the characteristic inclusions known as Pappenheimer bodies. - **Zinc deficiency** can impact immune function and growth, while excess can interfere with copper absorption.

Question 10: Which of the following findings is diagnostic of iron deficiency anemia?

A. Increased TIBC, decreased serum ferritin (Correct Answer)
B. Decreased TIBC, decreased serum ferritin
C. Increased TIBC, increased serum ferritin
D. Decreased TIBC, increased serum ferritin

Explanation: ***Increased TIBC, decreased serum ferritin*** - **Iron deficiency anemia** is characterized by depleted iron stores, leading to a **decreased serum ferritin** level, which is the most sensitive and specific marker for iron deficiency [4]. - In response to low iron stores, the body upregulates iron absorption and transport mechanisms, resulting in an **increased Total Iron Binding Capacity (TIBC)**, as there are more transferrin molecules available to bind iron [1]. *Decreased TIBC, decreased serum ferritin* - While a **decreased serum ferritin** is consistent with iron deficiency, a **decreased TIBC** is more indicative of **anemia of chronic disease** [1], where the body sequesters iron, leading to reduced iron availability for binding. - In **anemia of chronic disease**, both ferritin (an acute phase reactant) and TIBC can be reduced due to the inflammatory state [1], [2]. *Increased TIBC, increased serum ferritin* - An **increased TIBC** is seen in iron deficiency, but an **increased serum ferritin** indicates adequate or even **overloaded iron stores**, which contradicts the diagnosis of iron deficiency anemia. - High ferritin levels can be seen in conditions like **hemochromatosis** (iron overload) or **inflammation**, where ferritin acts as an acute phase reactant [5]. *Decreased TIBC, increased serum ferritin* - This combination is typical of **anemia of chronic disease**, where inflammation causes **increased serum ferritin** (as an acute phase reactant) and a **decreased TIBC** due to reduced production of transferrin [1]. - In this type of anemia, iron is often trapped within macrophages, making it unavailable for erythropoiesis despite seemingly normal or elevated stores [3].

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