Iron Deficiency Anemia (IDA) is the most common nutritional anemia worldwide and results from insufficient iron availability for hemoglobin synthesis, leading to reduced red blood cell (RBC) production and microcytic hypochromic anemia.

Iron is essential for:

• Hemoglobin synthesis

• Myoglobin formation

• Cellular respiration

• Enzymatic processes

Iron deficiency occurs due to blood loss, increased physiological demand, inadequate intake, or impaired absorption.

Pathophysiology

Iron depletion progresses in three stages:

1. Iron store depletion (↓ ferritin)

2. Iron-deficient erythropoiesis (↓ serum iron, ↑ TIBC)

3. Iron deficiency anemia (↓ Hb, microcytosis)

Chronic deficiency results in impaired oxygen delivery and tissue hypoxia.

Risk Factors

Increased Blood Loss

• Menorrhagia

• Gastrointestinal bleeding (peptic ulcer, malignancy)

• Hemorrhoids

• Hookworm infestation

• Frequent blood donation

Increased Demand

• Pregnancy

• Lactation

• Infancy and adolescence (growth spurts)

Decreased Intake

• Poor nutrition

• Vegetarian/vegan diet without supplementation

• Food insecurity

Malabsorption

• Celiac disease

• Inflammatory bowel disease

• Post-gastrectomy

• Chronic proton pump inhibitor use

Signs and Symptoms

General Symptoms

• Fatigue

• Weakness

• Palpitations

• Dizziness

• Dyspnea on exertion

• Headache

Characteristic Signs

• Pallor (conjunctival, palmar)

• Glossitis

• Angular cheilitis

• Koilonychia (spoon-shaped nails)

• Pica (craving for non-food substances)

• Brittle hair

• Restless legs syndrome (sometimes)

Severe or chronic cases may lead to:

• Tachycardia

• Cardiac failure (rare but possible)

Diagnostic Criteria

Diagnosis is based on:

1. Microcytic hypochromic anemia

2. Laboratory evidence of iron deficiency

3. Identification of underlying cause

Clinical signs such as pallor, glossitis, koilonychia, and pica support the diagnosis.

Investigations

1. Complete Blood Count (CBC)

• Low hemoglobin

• Low MCV (<80 fL)

• Low MCHC

• Elevated RDW (anisocytosis)

2. Peripheral Blood Smear

• Microcytic hypochromic RBCs

• Pencil cells (elliptocytes)

• Anisopoikilocytosis

3. Iron Studies

• ↓ Serum iron

• ↑ Total Iron Binding Capacity (TIBC)

• ↓ Transferrin saturation (<15%)

• ↓ Serum ferritin (most sensitive indicator)

Ferritin may be falsely normal or elevated in infection/inflammation.

4. Additional Investigations

• Stool examination (hookworm, occult blood)

• Upper and lower GI endoscopy (if GI bleeding suspected)

• Celiac screening (if malabsorption suspected)

• Pregnancy test (women of reproductive age)

Differential Diagnosis

• Thalassemia trait

• Anemia of chronic disease

• Sideroblastic anemia

• Lead poisoning

Distinguishing features:

Treatment

Treatment consists of correcting iron deficiency and addressing the underlying cause.

Non-Pharmacological Management

• Treat source of bleeding:

  • Menorrhagia

  • Peptic ulcer

  • GI malignancy

  • Hookworm infestation

• Nutritional counseling

• Iron-rich diet:

  • Red meat

  • Liver

  • Leafy greens

  • Legumes

• Vitamin C to enhance iron absorption

Blood transfusion is reserved for:

• Life-threatening anemia

• Hemodynamic instability

Pharmacological Management

Oral Iron Therapy (First-Line)

Ferrous sulfate 200 mg PO every 8 hours (adults)Children: 5 mg/kg PO every 8 hours

Continue therapy for:

• At least 3 months

• And for 3 months after normalization of hemoglobin to replenish iron stores

Expected response:

• Reticulocytosis within 7–10 days

• Hb rise ~1 g/dL every 2–3 weeks

Parenteral Iron Therapy (If Indicated)

Indications:

• Intolerance to oral iron

• Malabsorption

• Severe anemia needing rapid correction

• Chronic kidney disease

Preparations include:

• Iron sucrose

• Ferric carboxymaltose

Monitoring

• Hb after 2–4 weeks

• Ferritin after completion of therapy

• Evaluate compliance

• Reassess for ongoing bleeding if poor response

Complications

• Heart failure (severe cases)

• Impaired cognitive development (children)

• Preterm delivery (pregnancy)

• Reduced work capacity

• Increased infection susceptibility

Prevention

• Iron supplementation in pregnancy

• Deworming programs (endemic areas)

• Nutritional education

• Fortified foods

• Screening high-risk groups

• Management of chronic blood loss

Prognosis

• Excellent with appropriate therapy

• Recurrence likely if underlying cause untreated

• Long-term monitoring required in chronic conditions

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