What is the appropriate management for a patient with iron deficiency anemia, hyperglycemia, and signs of potential infection or inflammation?

Management of Iron Deficiency Anemia with Concurrent Inflammation

This patient has true iron deficiency anemia (ferritin 9 ng/mL, hemoglobin 8.2-11.6 g/dL) complicated by active inflammation (WBC 12.1, neutrophils 85.4%) and requires immediate intravenous iron therapy while addressing the underlying inflammatory process and hyperglycemia. 1, 2

Diagnostic Interpretation

The laboratory findings confirm absolute iron deficiency despite inflammation:

• Ferritin 9 ng/mL is unequivocally diagnostic of depleted iron stores, even in the presence of inflammation, as ferritin >100 ng/mL would be required to exclude iron deficiency in inflammatory states 1, 2
• The elevated WBC (12.1) with neutrophilia (85.4%) and lymphopenia (7.3%) indicates active infection or inflammation that must be identified and treated 1
• Hemoglobin dropped from 11.6 to 8.2 g/dL between measurements, indicating progressive anemia 1, 3
• Normal MCV (83.0) does not exclude iron deficiency, particularly in early stages or when concurrent B12 elevation (1,167) masks microcytosis 1, 3

Immediate Treatment Strategy

Intravenous iron is first-line therapy for this patient based on multiple criteria:

• Hemoglobin <100 g/L (8.2 g/dL) with active inflammation mandates intravenous iron rather than oral supplementation 1, 2
• The British Society of Gastroenterology confirms that oral iron absorption is impaired during active inflammation due to hepcidin upregulation, making it ineffective 1, 2
• The European Crohn's and Colitis Organisation meta-analysis demonstrated intravenous iron achieves hemoglobin rise of 2.0 g/dL more effectively than oral iron (OR: 1.57) with lower discontinuation rates (OR: 0.27) 1

Specific intravenous iron dosing:

• Administer 50-125 mg weekly for 8-10 doses, targeting ferritin 100-300 ng/mL and transferrin saturation >20% 2
• Recheck iron studies 8-10 weeks after completion, expecting hemoglobin improvement of 1-3 g/dL 2

Addressing the Inflammatory Component

The underlying inflammation must be identified and treated concurrently:

• Investigate infection sources given neutrophilia with lymphopenia pattern - consider urinalysis (already recommended), chest imaging, and blood cultures if febrile 1
• Screen for chronic inflammatory conditions: celiac disease serology (tissue transglutaminase IgA with total IgA), inflammatory bowel disease if gastrointestinal symptoms present, and autoimmune markers if clinically indicated 1, 2
• Evaluate for occult gastrointestinal bleeding with bidirectional endoscopy (upper and lower), as this is the most common cause of iron deficiency requiring investigation in adults 1, 3
• Test for Helicobacter pylori as atrophic gastritis impairs iron absorption 3, 4

Hyperglycemia Management

The glucose of 113 mg/dL requires assessment:

• Check hemoglobin A1c to distinguish stress hyperglycemia from diabetes mellitus 2
• Diabetes increases infection risk and may contribute to the inflammatory picture 2
• Optimize glycemic control as uncontrolled diabetes impairs wound healing and immune function 2

Renal Function Consideration

The eGFR of 60.98 mL/min indicates Stage 2-3 chronic kidney disease:

• This contributes to anemia through reduced erythropoietin production 1, 2
• In CKD, iron deficiency is diagnosed when transferrin saturation <20% and ferritin 100-700 ng/mL, but this patient's ferritin of 9 ng/mL confirms absolute deficiency regardless 1, 2
• Monitor for anemia of CKD as a contributing factor once iron stores are repleted 1

Critical Pitfalls to Avoid

Do not use oral iron in this clinical scenario:

• Active inflammation blocks intestinal iron absorption via hepcidin, rendering oral supplementation ineffective and causing gastrointestinal side effects without benefit 1, 2
• Only 21% of oral iron non-responders improve with continued oral therapy versus 65% with intravenous iron 1

Do not delay investigation for bleeding sources:

• Ferritin <15 ng/mL has 99% specificity for iron deficiency and mandates gastrointestinal evaluation in adults, regardless of age or sex 1
• The combination of severe anemia (hemoglobin 8.2 g/dL) with depleted iron stores suggests ongoing blood loss 1, 3

Do not rely on MCV alone:

• Normal MCV does not exclude iron deficiency, particularly with concurrent vitamin B12 elevation (1,167) that may mask microcytosis 1, 3
• The elevated RDW (17.7%) indicates mixed red cell populations consistent with evolving iron deficiency 1

Monitoring Protocol

After initiating intravenous iron:

• Recheck complete blood count and iron studies (ferritin, transferrin saturation) at 8-10 weeks 2
• Target hemoglobin improvement of 1-3 g/dL, ferritin 100-300 ng/mL, and transferrin saturation >20% 2
• Monitor every 3 months for the first year after correction, then periodically thereafter, as recurrent iron deficiency may indicate persistent inflammation 1
• Continue iron supplementation for 6 months after hemoglobin normalizes to fully replete iron stores 5