Anaemia - iron deficiency
Definition | Aetiology | Pathophysiology | Risk Factors | Signs and Symptoms | Investigations | Management
Definition
Iron deficiency anaemia (IDA) is a condition characterised by reduced haemoglobin levels due to insufficient iron, leading to impaired red blood cell production and oxygen transport.
Aetiology
- Dietary deficiency: inadequate iron intake (e.g., vegan or vegetarian diet).
- Blood loss: chronic gastrointestinal bleeding (e.g., peptic ulcer, malignancy, inflammatory bowel disease), heavy menstruation.
- Malabsorption: coeliac disease, atrophic gastritis, Helicobacter pylori infection.
- Increased demand: pregnancy, growth spurts in children.
Pathophysiology
- Iron is essential for haemoglobin synthesis; deficiency impairs erythropoiesis.
- Decreased iron stores lead to microcytic, hypochromic red blood cells.
- Reduced oxygen-carrying capacity results in fatigue, pallor, and other symptoms.
Risk Factors
- Poor dietary iron intake.
- Chronic blood loss (e.g., GI bleeding, menorrhagia).
- Malabsorptive conditions (e.g., coeliac disease, Crohn’s disease).
- Pregnancy and lactation.
Signs and Symptoms
- Fatigue, weakness.
- Pallor (conjunctival, palmar creases).
- Dyspnoea on exertion.
- Glossitis, angular cheilitis.
- Brittle nails, koilonychia (spoon-shaped nails).
- Pica (craving for non-food substances like ice or dirt).
Investigations
- Full blood count (FBC): microcytic, hypochromic anaemia.
- Serum ferritin: low, indicating depleted iron stores.
- Serum iron and transferrin saturation: reduced.
- Total iron binding capacity (TIBC): elevated.
- Coeliac screen: if malabsorption is suspected.
- Endoscopy/colonoscopy: if GI bleeding is suspected.
Management
1. Treat Underlying Cause:
- Manage sources of chronic blood loss (e.g., PPI for peptic ulcer, fibroid treatment).
- Address dietary insufficiencies with iron-rich foods.
2. Iron Supplementation:
- First line: generally ferrous sulfate 200 mg BD/TDS.
- Alternative: ferrous fumarate or ferrous gluconate for better tolerability.
- IV iron if oral therapy is ineffective or not tolerated.
3. Monitoring and Prevention:
- Repeat FBC and ferritin in 2-3 months to assess response.
- Long term supplementation if ongoing blood loss or malabsorption.
4. Referral:
- Gastroenterology: if GI bleeding is suspected.
- Gynaecology: for menorrhagia related iron deficiency.
- Haematology: if diagnosis is unclear or refractory IDA.