What is the recommended treatment for an adult patient with iron deficiency anemia, characterized by hypoferritinemia and hypoironemia?

Treatment of Iron Deficiency Anemia with Ferritin 9 and Serum Iron 35

Start oral iron replacement therapy immediately with ferrous sulfate 325 mg daily (or alternate-day dosing if not tolerated), while simultaneously investigating the underlying cause of this severe iron deficiency. 1

Diagnostic Confirmation

Your patient has confirmed iron deficiency anemia based on:

• Ferritin <15 μg/L is highly specific for iron deficiency (specificity 0.99), and your patient's ferritin of 9 μg/L indicates absent iron stores 1
• Low serum iron (35) further confirms absolute iron deficiency 1
• These values warrant both treatment and investigation regardless of hemoglobin level 1

Immediate Treatment Approach

First-line therapy:

• Ferrous sulfate 325 mg once daily (or ferrous fumarate or gluconate equivalent) 1
• If gastrointestinal side effects occur, reduce to alternate-day dosing rather than stopping treatment, as this maintains efficacy while improving tolerability 1
• Do not delay iron replacement while awaiting diagnostic workup unless colonoscopy is imminent 1

Monitoring response:

• Check hemoglobin after 2 weeks - expect rise of ≥10 g/L if true iron deficiency 1
• Continue monitoring every 4 weeks during initial treatment phase 1
• A good hemoglobin response confirms absolute iron deficiency even if other iron studies were equivocal 1

Mandatory Investigation

With ferritin this low, you must identify the source of iron loss:

Essential initial workup:

• Urinalysis or urine microscopy to exclude urinary blood loss 1
• Celiac disease screening (found in 3-5% of IDA cases) - use serology or small bowel biopsy at gastroscopy 1
• Detailed menstrual history in premenopausal women (most common cause in this population) 1, 2
• Gastrointestinal evaluation in men, postmenopausal women, or those with GI symptoms 1

Endoscopic evaluation:

• Bidirectional endoscopy (gastroscopy and colonoscopy) is first-line for men and postmenopausal women with newly diagnosed IDA 1
• CT colonography is acceptable alternative if colonoscopy not feasible 1
• Age, sex, and hemoglobin level are independent predictors of GI cancer risk and must factor into urgency of investigation 1

When to Consider Intravenous Iron

Switch to IV iron if: 1, 2

• Oral iron not tolerated despite alternate-day dosing
• Inadequate hemoglobin response after 4 weeks of oral therapy
• Ongoing blood loss that cannot be immediately controlled
• Malabsorption conditions (celiac disease, inflammatory bowel disease, post-bariatric surgery)
• Chronic inflammatory conditions (CKD, heart failure, IBD, cancer) where oral absorption is impaired 1, 2
• Second or third trimester pregnancy 2

Critical Pitfalls to Avoid

Common errors:

• Do not assume menstruation explains IDA in premenopausal women without excluding other causes - still perform celiac screening and consider GI evaluation if symptoms present or family history of GI pathology 1
• Do not use ferritin alone in inflammatory conditions - ferritin is an acute phase reactant and can be falsely normal; check transferrin saturation if inflammation suspected 1
• Do not stop investigating after negative initial endoscopy if IDA recurs or fails to respond - proceed to capsule endoscopy for small bowel evaluation and renal tract imaging 1

Long-term Management

• Recheck iron studies 8-10 weeks after starting treatment to assess response 3
• If IDA recurs after initial correction, consider long-term maintenance iron therapy while continuing to search for reversible causes 1
• Patients with recurrent IDA despite negative workup may require intermittent oral iron supplementation to maintain stores 3
• Monitor ferritin every 6-12 months in patients at ongoing risk (heavy menstruation, vegetarian diet, chronic inflammatory conditions) 3

Target ferritin for healthy adults is ≥30 μg/L to ensure adequate iron stores 3