Define Approach to a Child with Anaemia. Describe its classification, investigations and management.

Definition

• Anaemia is a reduction in the haemoglobin concentration (or red-cell mass) below the normal range for age and sex.
• Because normal values change with age, an age-appropriate cut-off must be used (e.g. WHO: Hb < 11 g/dL at 6 months–5 years).
• A systematic approach identifies the cause efficiently.

Two Useful Classifications

Anaemia can be approached morphologically (by MCV) and kinetically (by mechanism):

Morphological Classification (BY MCV)

Kinetic Classification (BY Mechanism)

• Decreased production — nutritional deficiency, marrow failure/infiltration, chronic disease.
• Increased destruction (haemolysis) — membrane, enzyme (G6PD), haemoglobin (thalassaemia, sickle) defects; immune haemolysis.
• Blood loss — acute or chronic.

The Reticulocyte Count (a Key Discriminator)

• High reticulocyte count → the marrow is responding → haemolysis or blood loss.
• Low reticulocyte count → a production defect (nutritional deficiency, marrow failure).

Clinical Evaluation

• History — diet, pica, blood loss, jaundice, drugs, family history (thalassaemia/haemolysis), age of onset, ethnicity.
• Examination — pallor, jaundice (haemolysis), hepatosplenomegaly and lymphadenopathy (haemolysis, leukaemia), bony changes, petechiae (marrow failure), koilonychia (IDA).

Investigations (stepwise)

• Haemogram with indices (MCV, MCH, RDW) and a peripheral smear — the essential first step.
• Reticulocyte count — to separate production from destruction/loss.
• Targeted tests — iron studies/ferritin (microcytic), HPLC (thalassaemia), B12/folate (macrocytic), Coombs test, G6PD, haemolysis markers (LDH, bilirubin) (haemolytic), and bone marrow (marrow failure/infiltration).

Peripheral Smear Clues

• Microcytic hypochromic + pencil cells → iron deficiency; target cells + basophilic stippling → thalassaemia.
• Macro-ovalocytes + hypersegmented neutrophils → megaloblastic; spherocytes → hereditary spherocytosis/immune haemolysis.
• Sickle cells → sickle disease; bite cells/Heinz bodies → G6PD deficiency; blasts → leukaemia.

Principle of Management

Management is directed at the specific cause identified — nutritional replacement, treatment of haemolysis/blood loss, or referral for marrow disease — rather than empirical transfusion, which is reserved for severe symptomatic anaemia.

Markers of Haemolysis

• Raised reticulocytes, unconjugated bilirubin and LDH; low haptoglobin.
• A positive direct Coombs test indicates immune haemolysis; blood-film morphology suggests the cause.

When to Refer

• Pancytopenia, blasts on the smear, or an unexplained non-nutritional anaemia.
• Suspected haemolysis, marrow failure or malignancy — for specialist evaluation and marrow study.

Key Principle

A logical, stepwise use of a few inexpensive tests (haemogram with indices, smear, reticulocyte count) identifies the mechanism in most children before committing to more expensive or invasive investigations.

Common Clinical Patterns (quick Recognition)

• Microcytic + low ferritin + high RDW → iron deficiency.
• Microcytic + normal ferritin + raised HbA2 → thalassaemia trait.
• Normocytic + high reticulocytes + jaundice → haemolysis.
• Macrocytic + hypersegmented neutrophils → megaloblastic anaemia.
• Pancytopenia → marrow failure or infiltration (needs marrow study).