What is the diagnosis and management for a 17-year-old female with mild iron deficiency anemia and abnormal complete blood count (CBC) results?

Management of Mild Iron Deficiency Anemia in a 17-Year-Old Female

Based on the CBC results showing low MCH and MCHC with high RDW, this patient has mild iron deficiency anemia requiring oral iron supplementation with ferrous sulfate 324 mg daily for 3 months to replenish iron stores.

Diagnosis Analysis

The patient's CBC shows several key findings pointing to iron deficiency anemia:

• Normal hemoglobin (13.8 g/dL) but with abnormal red cell indices
• Low MCH (25.8) - indicates hypochromia
• Low MCHC (30.5) - indicates reduced hemoglobin concentration
• High RDW-CV (15.4) - indicates increased variation in red cell size, typical in iron deficiency
• Normal MCV (84.5) - can be normal in early/mild iron deficiency
• High MPV (12.1) - often elevated in iron deficiency

These findings are consistent with early or mild iron deficiency anemia, where the hemoglobin may still be within normal range but red cell indices show characteristic changes 1, 2.

Confirmatory Testing

Before initiating treatment, the following tests should be ordered:

• Serum ferritin - most sensitive test for iron deficiency (diagnostic if <15 μg/L) 2
• Transferrin saturation - supportive if <20% 2
• CRP - to assess for inflammation (which can falsely elevate ferritin) 1

Treatment Plan

1. Oral iron supplementation:

   • Ferrous sulfate 324 mg daily (providing 65 mg elemental iron) 2, 3
   • Alternative dosing: 200 mg three times daily if more rapid correction needed 2
   • Take on empty stomach with vitamin C-containing drink to enhance absorption
   • Consider alternate-day dosing if GI side effects occur (may improve absorption) 4

2. Duration of therapy:

   • Continue for 3 months after normalization of hemoglobin to replenish iron stores 1, 2

3. Monitoring response:

   • Check hemoglobin after 2-4 weeks of therapy (should rise by 1-2 g/dL) 2
   • Monitor ferritin and transferrin saturation after 2-4 weeks 2
   • Follow-up CBC at 3-month intervals for one year, then after another year 1, 2

Investigation of Underlying Cause

Given the patient's age and gender, the most likely causes include:

1. Menstrual blood loss:

   • Assess menstrual history for menorrhagia using pictorial blood loss assessment charts 1
   • Consider gynecological evaluation if heavy menstrual bleeding is present

2. Dietary factors:

   • Evaluate dietary iron intake
   • Assess for vegetarian/vegan diet or other restrictive eating patterns

3. Malabsorption:

   • Consider screening for celiac disease (especially with normal MCV) 2
   • Evaluate for other GI symptoms suggesting malabsorption

4. GI blood loss:

   • Less common in this age group but should be considered if no other cause identified
   • Consider stool occult blood testing if no obvious cause found

Management of Side Effects

Common side effects of oral iron include:

• Constipation
• Nausea
• Abdominal discomfort
• Black stools

Management strategies:

• Start with lower doses and gradually increase
• Consider alternate-day dosing
• Try different iron formulations if intolerance occurs (ferrous gluconate or ferrous fumarate) 2
• Take with food if necessary, despite reduced absorption

Special Considerations for Adolescent Females

• Increased iron requirements during adolescence due to growth and menstruation
• Dietary counseling to increase iron-rich foods
• Consider vitamin C supplementation with meals to enhance iron absorption
• Address any disordered eating patterns that may contribute to iron deficiency

When to Consider Parenteral Iron

Intravenous iron should be considered if:

• Intolerance to at least two oral iron preparations
• Non-compliance with oral therapy
• Malabsorption disorders
• Need for rapid iron repletion 2, 4

Pitfalls to Avoid

• Failing to continue iron supplementation for adequate duration (3 months after normalization)
• Not addressing the underlying cause of iron deficiency
• Misinterpreting ferritin levels in the presence of inflammation
• Overlooking the possibility of combined deficiencies (iron and B12/folate)
• Assuming normal hemoglobin excludes iron deficiency 2

This approach prioritizes addressing the patient's iron deficiency to prevent progression to more severe anemia and associated morbidity, while systematically investigating potential underlying causes appropriate for a 17-year-old female.