Patient with hemoglobin 8.2 g/dL, hematocrit 28.1 %, mean corpuscular volume 79 fL, red cell distribution width 15.4 % and ferritin ≈4 ng/mL – what is the diagnosis and recommended initial management?

Severe Iron Deficiency Anemia

This patient has severe iron deficiency anemia requiring immediate oral or intravenous iron supplementation, with the ferritin of approximately 4 ng/mL being diagnostic of absolute iron deficiency regardless of inflammation status. 1

Diagnosis

The laboratory values confirm severe iron deficiency anemia:

• Hemoglobin 8.2 g/dL represents moderate anemia (below the normal range of >12 g/dL for women or >13 g/dL for men) 1
• MCV 79 fL indicates microcytic anemia, characteristic of iron deficiency 1
• RDW 15.4% (elevated) reflects anisocytosis, which supports iron deficiency and helps distinguish it from thalassemia trait 2, 3
• Ferritin ≈4 ng/mL is unequivocally diagnostic of iron deficiency, as values <12 ng/mL confirm absolute iron deficiency even without considering inflammation 1

The combination of microcytosis, elevated RDW, and severely low ferritin makes iron deficiency anemia the definitive diagnosis. 1

Immediate Management: Iron Replacement

Oral iron therapy should be initiated immediately as first-line treatment for this patient without chronic kidney disease or inflammatory bowel disease. 1

Oral Iron Regimen

• Ferrous sulfate 325 mg (65 mg elemental iron) once to three times daily on an empty stomach for optimal absorption 1
• A therapeutic trial of three weeks of oral iron should demonstrate hemoglobin response if iron deficiency is the primary cause 1
• Continue treatment for 3-6 months after hemoglobin normalizes to replenish iron stores 1

When to Consider Intravenous Iron

Intravenous iron should be considered if: 1

• The patient cannot tolerate oral iron due to gastrointestinal side effects
• There is malabsorption (e.g., celiac disease, inflammatory bowel disease)
• The patient requires rapid correction (e.g., upcoming surgery)
• Oral iron fails after adequate trial

Essential Investigations to Identify the Source

All patients with iron deficiency anemia must undergo investigation to identify the underlying cause, as gastrointestinal blood loss or malabsorption are the most common etiologies in adults. 1

Required Gastrointestinal Evaluation

• Upper endoscopy with duodenal biopsies to exclude gastric cancer, peptic ulcer disease, celiac disease, and other upper GI sources 1
• Colonoscopy or barium enema to exclude colorectal cancer, polyps, angiodysplasia, and inflammatory bowel disease 1
• Both upper and lower GI tract examination should be performed even in the absence of GI symptoms, as asymptomatic malignancies commonly present with iron deficiency anemia 1

Additional Considerations

• Dietary history to assess iron intake, though inadequate diet alone rarely causes severe anemia in adults 1
• Medication review for NSAIDs, aspirin, and anticoagulants that may cause occult bleeding 1
• Menstrual history in premenopausal women, as heavy menstrual bleeding is a common cause 1
• Celiac serology (tissue transglutaminase antibodies) if duodenal biopsies are not obtained 1

Monitoring Response to Treatment

• Repeat complete blood count after 3 weeks of oral iron to confirm hemoglobin rise of ≥1 g/dL, which indicates appropriate response 1
• Reticulocyte count should increase within 7-10 days of starting iron therapy 1
• If no response occurs after adequate oral iron trial, consider: 1
  • Non-compliance
  • Ongoing blood loss exceeding replacement
  • Malabsorption
  • Incorrect diagnosis (e.g., thalassemia trait, anemia of chronic disease)
  • Need for intravenous iron

Transfusion Considerations

Red blood cell transfusion is generally NOT indicated at hemoglobin 8.2 g/dL unless the patient has:

• Severe symptomatic anemia (profound weakness, angina, dyspnea at rest) 1, 4
• Hemodynamic instability 4
• Acute cardiovascular events 1, 4
• Significant cardiovascular disease with symptoms 1

A restrictive transfusion strategy (transfusing only when Hb <7-8 g/dL in stable patients) is associated with lower rates of myocardial infarction and pulmonary edema compared to liberal transfusion strategies. 1

Common Pitfalls to Avoid

• Do not assume dietary deficiency is the sole cause without investigating for GI pathology, as occult malignancy must be excluded 1
• Do not delay investigation while treating with iron, as early detection of malignancy significantly impacts prognosis 1
• Do not interpret ferritin >100 ng/mL as excluding iron deficiency in patients with inflammation, chronic disease, or malignancy, though this patient's ferritin of 4 ng/mL is unequivocally diagnostic 1
• Do not overlook celiac disease, which is a common but frequently missed cause of iron deficiency anemia due to malabsorption 1