What is the appropriate management for a patient with mild anemia and normal MCV, MCH, and RDW?

Management of Mild Normocytic Anemia in a 60-Year-Old Male

This patient requires a comprehensive diagnostic workup to identify the underlying cause of anemia, with particular emphasis on excluding gastrointestinal malignancy and evaluating for chronic disease, as mild anemia is equally indicative of serious pathology as severe anemia. 1

Initial Diagnostic Workup

The following laboratory tests must be obtained immediately:

• Iron studies: Serum ferritin (most powerful single test for iron deficiency), transferrin saturation, and total iron-binding capacity 1, 2
• Inflammatory markers: C-reactive protein (CRP) to assess for anemia of chronic disease 1, 3, 2
• Reticulocyte count: To distinguish between impaired red cell production versus increased destruction or blood loss 1, 3, 2
• Vitamin B12 and folate levels: To exclude nutritional deficiencies that can present with normocytic anemia or mask microcytosis in combined deficiencies 1, 2
• Renal function: Serum creatinine and estimated GFR to evaluate for chronic kidney disease as a cause of normocytic anemia 3, 2
• Peripheral blood smear: To assess red cell morphology and identify abnormalities not apparent from indices alone 1

Interpretation of Iron Studies

Critical thresholds for diagnosis:

• Without inflammation: Serum ferritin <30 μg/L indicates iron deficiency 1, 3
• With inflammation present: Ferritin up to 100 μg/L may still be consistent with iron deficiency 1
• Transferrin saturation <30% supports iron deficiency diagnosis 1

Mandatory Gastrointestinal Investigation

In a 60-year-old male with anemia, gastrointestinal blood loss is the most common cause and asymptomatic malignancy must be excluded. 1

The following investigations are mandatory:

• Upper gastrointestinal endoscopy with small bowel biopsy: To exclude gastric cancer, peptic ulcer disease, angiodysplasia, and celiac disease 1, 2
• Colonoscopy or barium enema: To exclude colonic cancer, polyps, inflammatory bowel disease, and other sources of occult bleeding 1

These investigations should proceed regardless of whether iron deficiency is confirmed, as even mild anemia warrants complete evaluation in this demographic. 1

Differential Diagnosis Considerations

Given the normal MCV, MCH, and RDW, the following etiologies are most likely:

• Early iron deficiency: Iron deficiency can present with normocytic indices before microcytosis develops 2
• Anemia of chronic disease/inflammation: Typically presents with normocytic or mildly microcytic anemia with elevated ferritin and CRP 1, 4
• Chronic kidney disease: Produces normocytic/normochromic anemia that becomes more prevalent as GFR declines 2
• Combined deficiencies: Concurrent iron and B12/folate deficiency can neutralize each other, resulting in normal MCV despite significant abnormalities 1, 2
• Occult blood loss: May present with normocytic anemia before iron stores are depleted 1

Common Pitfalls to Avoid

• Never assume normocytic anemia excludes iron deficiency: Early iron deficiency presents with normal MCV, and the normal RDW in this case does not rule out iron deficiency 2
• Do not overlook mixed deficiencies: Concurrent nutritional deficiencies can mask typical findings 1, 2
• Do not delay gastrointestinal investigation: In men and post-menopausal women, GI malignancy must be excluded regardless of iron studies 1, 2
• Assess medication history: NSAIDs, aspirin, and anticoagulants can cause occult GI bleeding 1

Treatment Approach

Treatment should be deferred until the underlying cause is identified, as the etiology will dictate appropriate management:

• If iron deficiency is confirmed: Oral iron supplementation after GI evaluation 3
• If anemia of chronic disease: Address the underlying inflammatory condition 3
• If CKD-related: Consider iron therapy first, then erythropoietin if anemia persists despite adequate iron stores 3
• If malignancy is detected: Treatment of the underlying malignancy will often correct the anemia 1

The long-term outlook is good even when no cause is detected, but thorough investigation is mandatory to exclude life-threatening conditions. 1