Iron Deficiency Anemia Overview
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Questions and Answers

What effect does hypoxia have on hepcidin synthesis?

  • Suppresses hepcidin synthesis (correct)
  • Increases hepcidin synthesis
  • Increases iron absorption
  • Has no effect on hepcidin synthesis

Increased erythropoiesis leads to an increase in hepcidin synthesis.

False (B)

What laboratory finding is indicated by low ferritin levels?

Iron deficiency

Iron is primarily transported in the bloodstream by ______.

<p>transferrin</p> Signup and view all the answers

Match the following types of anemia with their causes:

<p>Thalassaemia = Genetic mutations affecting haemoglobin production Anaemia of chronic disease = Chronic inflammation leading to low iron availability Sideroblastic anaemia = Deficiency of Aminolevulinic Acid (ALA) enzyme Iron deficiency anemia = Insufficient iron intake or absorption</p> Signup and view all the answers

Which of the following mechanisms is responsible for iron absorption in the duodenum?

<p>Divalent Metal Transporter 1 (DMT-1) (A), Haem receptors (C)</p> Signup and view all the answers

Transferrin is a protein that stores iron in the liver and spleen.

<p>False (B)</p> Signup and view all the answers

Name one of the primary causes of iron deficiency anemia.

<p>Blood loss, Inadequate intake, Malabsorption, or Increased demand</p> Signup and view all the answers

Iron is primarily stored in the body as __________.

<p>ferritin</p> Signup and view all the answers

Match the following terms related to iron regulation with their functions:

<p>Transferrin = Transports iron in the bloodstream Ferritin = Stores iron in cells DMT-1 = Facilitates iron absorption in the intestine Hepcidin = Regulates iron homeostasis by inhibiting absorption</p> Signup and view all the answers

What is the effect of binding of IRP to the Iron Response Element (IRE) when iron levels are low?

<p>Increased translation of mRNA (A)</p> Signup and view all the answers

In iron overload, IRP/IRE binding is increased.

<p>False (B)</p> Signup and view all the answers

What is the role of hepcidin in iron metabolism?

<p>To regulate iron absorption and release from macrophages</p> Signup and view all the answers

Hepcidin is produced in the ______.

<p>liver</p> Signup and view all the answers

Match the following regulatory elements with their functions:

<p>TfR1 = Increased iron uptake DMT-1 = Iron transport across cell membranes Ferritin = Iron storage Hepcidin = Regulates iron absorption</p> Signup and view all the answers

What happens to TfR2 levels when iron levels are elevated?

<p>TfR2 levels decrease (C)</p> Signup and view all the answers

Haemochromatosis is related to a deficiency in iron absorption.

<p>False (B)</p> Signup and view all the answers

How does increased hepcidin affect iron absorption in the small intestine?

<p>It reduces iron absorption</p> Signup and view all the answers

Flashcards

Reduced Hepcidin Production

Reduced production of the protein hepcidin, which regulates iron absorption, leading to excessive iron absorption.

Microcytic/Hypochromic Anemia

A type of anemia characterized by small, pale red blood cells, due to insufficient iron in RBCs.

Low Ferritin

A low level of ferritin in the blood, often indicating iron deficiency. Ferritin stores iron.

Elevated Zinc Protoporphyrin (ZPP)

Higher than normal levels of zinc protoporphyrin in the blood, often associated with an iron deficiency. Zinc takes the place of iron in red blood cells.

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Causes of Microcytic Anemia

Anemia with small red blood cells can be caused by several conditions like thalassemia, anemia of chronic disease, or sideroblastic anemia.

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Iron Deficiency Anemia Symptoms

Symptoms of low haemoglobin include tiredness, breathlessness, pale skin (pallor), and potential cardiovascular issues.

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Causes of Iron Deficiency Anemia

Iron deficiency anemia can arise from blood loss, insufficient intake, malabsorption, or increased body demand.

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Iron Absorption Process

Dietary iron is absorbed in the duodenum. Iron from meat (heme) and non-meat sources (non-heme) differ in absorption pathways.

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Iron Regulation Cycle

Iron absorption, transport, use in red blood cell production, and storage in the body are a tightly controlled cycle of the body.

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Iron Storage Forms

Iron is stored in the body as ferritin or hemosiderin, primarily in the liver, spleen, and bone marrow.

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IRP/IRE binding

Iron Regulatory Protein (IRP) binding to Iron Response Element (IRE) structures in mRNA affects translation of ferritin, TfR1, and DMT-1.

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Ferritin mRNA IRE location

The Iron Response Element (IRE) in ferritin mRNA is located at the 5' end, influencing translation.

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TFR1/DMT-1 mRNA IRE location

The IRE in TFR1 and DMT-1 mRNA is at the 3' end, affecting mRNA stability and translation.

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Hepcidin's Role

Hepcidin, a liver-produced hormone, regulates iron absorption and release, affecting iron levels in the body by regulating ferroportin's activity.

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Iron Overload and Hepcidin

High iron levels stimulate hepcidin production, decreasing iron absorption and release.

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Iron Deficiency and Hepcidin

Low iron levels decrease hepcidin production, increasing iron absorption.

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Hepcidin Activity

Hepcidin accelerates the degradation of ferroportin, a transmembrane iron exporter.

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Haemochromatosis

A condition with a mutation in the HFE gene, leading to issues of iron-absorption control.

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Study Notes

Iron Deficiency Anemia

  • Symptoms of Low Hemoglobin (Hb):

    • Tiredness
    • Breathlessness
    • Pallor
    • Cardiovascular symptoms
  • 4 Main Causes of Iron Deficiency Anemia (IDA):

    • Blood loss
    • Inadequate iron intake
    • Malabsorption
    • Increased iron demand

Iron Regulation Cycle

  • Dietary iron is absorbed by microvilli in the small intestine (duodenum).
  • Iron enters the bloodstream and is transported by transferrin (protein) to bone marrow or the liver.
  • Iron is used in bone marrow for red blood cell (RBC) production.
  • Iron is stored in the liver as ferritin.

Dietary Iron Absorption and Regulation

  • Dietary iron intake is approximately 10-15 mg/day, with only about 1 mg absorbed.
  • Iron from meat is absorbed via haem receptors.
  • Non-haeme iron is reduced to Fe2+ by ferrireductase, then absorbed via DMT-1.
  • Absorbed iron is either stored as ferritin or enters the bloodstream via ferroportin.
  • Transferrin transports iron to bone marrow or other tissues

Iron Storage

  • Iron is stored as ferritin or haemosiderin.
  • Ferritin contains an iron-hydroxide-phosphate compound.

Iron Regulation

  • Iron levels are controlled by four key stages:

    • Iron import from the intestine to the enterocyte via DMT-1
    • Iron export from the enterocyte into the circulation via ferroportin
    • Ferritin synthesis
    • TfR-1 (transferrin receptor 1) synthesis
  • Gene Regulation:

    • Iron status controls ferritin, TfR1, and DMT-1 genes.
    • High iron levels increase ferritin production, and decrease TfR1 and DMT-1.
    • Low iron levels decrease ferritin production, and increase TfR1 and DMT-1
  • Hormone Regulation (Hepcidin):

    • A polypeptide hormone produced in the liver.
    • Its production is controlled by iron levels, inflammation, cytokines, erythropoiesis, and hypoxia.
    • Increased hepcidin leads to reduced iron absorption in the small intestine and reduced release of iron from macrophages.

Laboratory Findings

  • FBC: Low hemoglobin (Hb), low mean corpuscular volume (MCV), low mean corpuscular hemoglobin (MCH).
  • Blood film: Microcytic/hypochromic anemia
  • Red Cell Distribution Width (RDW): Measures variation in red blood cell size (higher value = greater variation)
  • Ferritin: Low levels
  • Zinc Protoporphyrin (ZPP): Elevated levels
  • Serum iron: (Not very useful)
  • Total Iron Binding Capacity (TIBC): Low transferrin saturation

Differential Diagnosis of Microcytic/Hypochromic Anemia

  • Thalassemias: Genetic mutations affecting hemoglobin production
  • Anemia of chronic disease:
  • Sideroblastic anemia: Deficiency of aminolevulinic acid enzyme causing iron accumulation in mitochondria of red blood cells.

Additional Notes

  • Iron accounts for 20% of its body weight.
  • Old red blood cells are broken down by macrophages, releasing iron from hemoglobin, which the body transports to bone marrow for reuse.

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Description

Explore the key aspects of iron deficiency anemia, including its symptoms, causes, and the regulation of dietary iron absorption. This quiz covers how iron is utilized and stored in the body and the processes involved in the formation of red blood cells. Test your knowledge about this crucial health topic.

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