What is the pathophysiology of iron deficiency anemia (IDA)?

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From the Guidelines

Iron deficiency anemia develops through a progressive depletion of iron stores in the body, leading to impaired hemoglobin production and reduced oxygen-carrying capacity. This condition can be caused by various factors, including chronic blood loss, inadequate dietary intake, malabsorption, or increased requirements 1. The pathophysiology of iron deficiency anemia involves a spectrum of stages, ranging from iron depletion to iron-deficiency anemia, with the most severe form characterized by underproduction of iron-containing functional compounds, including hemoglobin 1.

Key Factors Contributing to Iron Deficiency Anemia

  • Chronic blood loss, such as menstruation or gastrointestinal bleeding
  • Inadequate dietary intake of iron
  • Malabsorption of dietary iron, often due to conditions like celiac disease or gastric bypass
  • Increased requirements for iron, as seen in pregnancy or childhood growth

Clinical Presentation and Diagnosis

Symptoms of iron deficiency anemia develop gradually and may include fatigue, weakness, pallor, headaches, and in severe cases, tachycardia and dyspnea on exertion 1. Diagnosis is typically made through blood tests, and treatment requires addressing the underlying cause and replenishing iron stores through oral supplements or intravenous iron in cases of severe deficiency or malabsorption 1.

Importance of Investigating Underlying Causes

It is crucial to investigate the underlying cause of iron deficiency anemia, especially in adults without an obvious explanation, as it may be indicative of serious gastrointestinal pathology, including cancer 1. Prompt and complete investigation is essential to ensure timely diagnosis and treatment of any underlying conditions.

From the Research

Pathophysiology of Iron Deficiency Anemia

The pathophysiology of iron deficiency anemia involves a complex interplay of factors that lead to a decrease in iron stores, resulting in a reduction in hemoglobin production and ultimately, anemia.

  • Iron deficiency anemia arises when the balance of iron intake, iron stores, and the body's loss of iron are insufficient to fully support production of erythrocytes 2.
  • The most common causes of iron deficiency are bleeding (menstrual, gastrointestinal), impaired iron absorption (atrophic gastritis, celiac disease, bariatric surgical procedures), inadequate dietary iron intake, and pregnancy 3.
  • Iron deficiency can progress from low iron stores to iron-deficiency anemia, with individuals experiencing symptoms such as fatigue, irritability, depression, difficulty concentrating, restless legs syndrome, and dyspnea 3.

Diagnosis of Iron Deficiency Anemia

Diagnosing iron deficiency anemia can be challenging, but several tests are available to help identify the condition.

  • Serum ferritin measurement is the most important analysis in the study of iron deficiency, but there is no consensus on the diagnostic cut-off 4.
  • Transferrin saturation, serum iron, and soluble transferrin receptor are also used to diagnose iron deficiency, but these tests can be affected by inflammation and other factors 5, 6.
  • Reticulocyte hemoglobin content (CHr) is a useful marker for diagnosing iron deficiency and monitoring iron therapy, as it is less affected by inflammation than other tests 5.

Risk Factors and Prevention

Certain individuals are at higher risk of developing iron deficiency anemia, including:

  • Women of childbearing age, particularly those with heavy menstrual bleeding 3.
  • Pregnant women, especially during the third trimester 3.
  • Individuals with chronic inflammatory conditions, such as chronic kidney disease, heart failure, and cancer 3, 6.
  • Prevention and early detection of iron deficiency anemia are crucial to reducing the impact of this condition on human health, particularly in underdeveloped countries 2.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Iron deficiency anemia: a common and curable disease.

Cold Spring Harbor perspectives in medicine, 2013

Research

[Iron deficiency anaemia--interpretation of biochemical and haematological findings].

Tidsskrift for den Norske laegeforening : tidsskrift for praktisk medicin, ny raekke, 2013

Research

Assessing iron status: beyond serum ferritin and transferrin saturation.

Clinical journal of the American Society of Nephrology : CJASN, 2006

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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