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Iron Deficiency Anemia

*Anaemia ferripriva*

For medical students2 min readUpdated 2026-10-10

Iron deficiency anemia is a condition caused by the depletion of the body's iron stores, leading to impaired hemoglobin synthesis. The primary underlying mechanism is chronic blood loss, resulting in hypochromic microcytic anemia.

Primary CauseChronic blood loss (menstruation, peptic ulcers, hemorrhoids, malignancies).
Blood MorphologyHypochromia, microcytosis, and poikilocytosis of erythrocytes.
Marker of StoresDecreased serum ferritin levels.
SideropeniaKoilonychia, angular stomatitis, atrophic glossitis.

Pathogenesis and Etiology

The adult human body contains 3–4 g of iron, the majority of which is incorporated into hemoglobin. Deficiency occurs during a negative iron balance: when losses exceed intake or absorption.

Key etiological factors:

  1. Chronic blood loss: Losing 10–15 mL of blood per day critically depletes iron stores.
  2. Dietary factor: Insufficient dietary intake.
  3. Malabsorption: Impaired absorption due to small bowel pathology, achlorhydria, or following gastrectomy.

Clinical Manifestations

In addition to general signs of anemia, patients develop sideropenic syndrome, associated with a deficiency of iron-containing enzymes in tissues:

Diagnostics

The laboratory profile is characterized by decreased levels of serum iron and ferritin. Peripheral blood smears demonstrate microcytosis and hypochromia. In severe deficiency, annulocytes (target cells/ring cells) and ovalocytes appear.

Prussian blue staining of the bone marrow reveals an absence of hemosiderin stores, serving as a key diagnostic criterion.

Mnemonic

"IDA is a MIG: Microcytosis, Inversion (of nails/mucosa), Hypochromia."

Frequently asked questions

Which biochemical serum markers change in iron deficiency anemia?

In iron deficiency anemia, markers reflecting depleted stores and compensatory increases in transport capacity are altered.

Decreased parameters include:

  • Serum iron — drops below normal limits.
  • Serum ferritin — the main indicator of tissue stores (drops below 10 mcg/L).
  • Transferrin saturation coefficient — 15% or lower.

Increased biochemical markers include:

  • Total iron-binding capacity (TIBC).
  • Latent iron-binding capacity (UIBC).
  • Transferrin — the free iron transport protein.

These parameters respond to iron deficiency early on and change uniformly.

What stages are distinguished in the pathogenesis of iron deficiency development in the body?

Sources indicate that during a negative iron balance, the depletion process occurs sequentially, identifying 4 stages of sideropenia.

Confirmed sequence of iron deficiency development:

  • First, tissue iron reserves are mobilized and depleted.
  • Ferritin and hemosiderin levels decrease.
  • A drop in hemoglobin iron, i.e., the manifestation of anemia, occurs only after total depletion of storage depots.

Iron deficiency also triggers two parallel pathological pathways:

  • Hematologic pathway: slowed heme synthesis → suppressed hemoglobin formation → anemia → hypoxia, tissue, and organ damage.
  • Tissue pathway: impaired synthesis of iron-containing compounds, including enzymes and myoglobin → decreased antioxidant activity → intensified lipid peroxidation → tissue and organ damage.
Which specific tissue enzyme activities decrease in sideropenic syndrome?

Sideropenic syndrome impairs the structure and reduces the activity of iron-containing enzymes and compounds. Sources indicate:

  • Cytochromes.
  • Catalase.
  • Peroxidases, including glutathione peroxidases.
  • Xanthine oxidase.
  • Ribonucleotide reductase.

These impairments are linked to the deficiency of iron-containing enzymes and compounds, tissue hypoxia, decreased activity of antioxidant factors, intensification of lipid peroxidation, and tissue/organ damage.

How does anemia of chronic disease differ from iron deficiency anemia?

In anemia of chronic disease, serum ferritin is normal or elevated, and iron is sequestered in macrophages, whereas in IDA, iron stores are depleted.

What are ringed sideroblasts?

These are erythroblasts with excessive iron accumulation in mitochondria surrounding the nucleus, characteristic of sideroblastic anemias rather than IDA.

Why does atrophic gastritis occur in iron deficiency anemia?

Atrophic gastritis can be both a cause (via achlorhydria) and a consequence of iron deficiency, creating a vicious cycle of impaired absorption.

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