Hb <13 g/dL (men) or <12 g/dL (non-pregnant women); reduction in red cell mass.
History taking
- • Fatigue, dyspnoea on exertion, palpitations, pica, restless legs
- • Menstrual history, GI bleeding (melaena, haematochezia), NSAID/alcohol use
- • Diet (iron, B12, folate), pregnancy, recent illness, chronic disease
Examination
- • Pallor (conjunctiva, palms, tongue), tachycardia, flow murmur
- • Glossitis, koilonychia, angular cheilitis (Fe def.)
- • Jaundice, splenomegaly (haemolysis)
- • PR exam for melaena
Red flags
- • Hb <7 g/dL with symptoms, ongoing bleeding
- • Pancytopenia, blasts on smear
- • Suspected GI/uterine malignancy
Differential diagnosis
- • Microcytic: iron deficiency, thalassaemia, anaemia of chronic disease
- • Macrocytic: B12/folate deficiency, hypothyroidism, alcohol, MDS
- • Normocytic: ACD, CKD, haemolysis, marrow failure
Recommended investigations
- • CBC with indices (MCV, MCH, RDW), peripheral smear, reticulocyte count
- • Iron studies (ferritin, TIBC, transferrin saturation)
- • Serum B12, folate; LDH, bilirubin, haptoglobin if haemolysis
- • Stool occult blood, endoscopy/colonoscopy if IDA in male/postmenopausal female
Diagnosis
- • Classify by MCV first, then by underlying cause
Initial treatment / management
- • Treat underlying cause (bleeding source, dietary)
- • Iron: Oral ferrous sulphate 100–200 mg elemental/day OR alternate-day dosing
- • IV iron if intolerance or malabsorption
- • Transfusion if Hb <7 (or <8 with cardiac disease) and symptomatic
Prescription examples
- • Tab Ferrous Ascorbate 100 mg PO OD between meals x 3 months
- • Inj Iron sucrose 200 mg IV in 100 mL NS over 30 min — total dose by Ganzoni
- • Inj Vit B12 1000 µg IM alternate day x 5, then weekly x 4, then monthly
- • Tab Folic acid 5 mg PO OD x 4 months
Follow-up advice
- • Recheck Hb in 4 weeks (expect rise ≥1 g/dL)
- • Continue iron 3 months after Hb normalises to replete stores
Patient counselling
- • Iron-rich diet (green leafy, jaggery, meat); take iron with citrus, avoid tea/coffee/milk
- • Side-effects: black stools, constipation
- • Investigate cause — don't just replace
Referral criteria
- • Suspected malignancy, marrow failure
- • Refractory anaemia, transfusion dependence
- • Haemolytic anaemia for haematology
Clinical pearls
- • Ferritin <30 = iron deficiency (irrespective of MCV)
- • RDW high + MCV low → IDA; RDW normal + MCV low → thalassaemia trait
- • Always investigate IDA in adult male / postmenopausal female for GI malignancy
References
- • WHO Hemoglobin thresholds for anaemia 2024
- • BSH Guidelines on Iron Deficiency Anaemia 2021
Educational outpatient guide — verify against local guidelines before clinical use.
