Iron Deficiency Anemia

Overview

• Most common cause of anemia worldwide
• In the developing world: nutritional deficiency
• In the developed world: acute blood loss (e.g., GI bleeding or peptic ulcer disease)
• Most common cause of nutritional deficiency worldwide

At-Risk Populations

• Females: Due to menstruation
• Children: Due to decreased intake and high demand from growth
• Premature babies: Risk from inadequate iron
• People in poverty: Nutritional deficiencies
• Elderly: Similar risk as children
• Strict vegans: Higher risk due to lower absorption of non-heme iron

Causes

1. Decreased Supply: Poor nutrition, malabsorption (e.g., celiac disease, post-gastric surgery)
2. Increased Demand: Pregnancy, lactation, growth
3. Loss: Blood loss (e.g., peptic ulcers, GI conditions), hemolysis

Hemoglobin and Iron

• Hemoglobin = Heme + Globin
• Heme = Iron + Protoporphyrin
• In iron deficiency anemia:
  • Decreased iron -> Decreased heme -> Decreased hemoglobin -> Anemia

Characteristics of Iron Deficiency Anemia

• Microcytic anemia (small red blood cells)
  • Due to cells waiting for iron and getting smaller
• Common symptoms: Tiredness, paleness, sometimes angina, irritability, exercise intolerance
• Plummer-Vinson syndrome: Associated conditions like esophageal webs, glossitis
• Restless Leg Syndrome: Unknown reason for association
• Koilonychia (spoon-shaped nails)
• Beeturia (red urine after eating beets)
• Pica (craving ice or ice-containing items)

Diagnostic Lab Findings

• Hemoglobin: Decreased
• MCV: Microcytic (low)
• MCH and MCHC: Low
• Reticulocytes: Low
• White blood cells: Usually normal except with hookworm infections
• Platelets: May increase
• Iron Studies:
  • Serum iron: Decreased
  • Ferritin: Decreased (an acute phase reactant; unreliable if inflammation present)
  • TIBC: Increased
  • % Saturation: Decreased
  • Soluble transferrin receptor assay: Increased
  • RDW (Red Cell Distribution Width): High due to varied cell sizes

Diagnostic Test

• Most accurate: Bone marrow biopsy (usually avoided due to invasiveness)
• Simple alternative: Iron supplementation trial; improvement confirms iron deficiency anemia

Treatment

• First Line: Oral ferrous sulfate
  • Side effects: Diarrhea, constipation, black stool (guaiac negative)
• Non-responsive Cases: Consider celiac disease, ongoing blood loss, poor absorption
• Second Line: Intramuscular or intravenous iron (risk of anaphylaxis, especially with dextran)

Summary

• Iron deficiency anemia results from decreased iron affecting hemoglobin production
• Key signs include microcytic anemia and low iron measures in blood tests
• Treated primarily through iron supplementation, considering absorption and ongoing blood loss issues