What is the workup and management for a female patient in her 40s with iron deficiency anemia?

Management of Iron Deficiency Anemia in a Female Patient in Her 40s

Start with oral ferrous sulfate 200 mg once daily (or alternate-day dosing if better tolerated), add vitamin C 500 mg to enhance absorption, and investigate for underlying causes with upper endoscopy plus small bowel biopsy and colonoscopy, while screening for celiac disease. 1, 2

Diagnostic Workup

Age-Based Investigation Strategy

• Women over 45 years require full gastrointestinal investigation including upper endoscopy with small bowel biopsies and colonoscopy (or barium enema if colonoscopy unavailable), as the risk of serious pathology increases significantly with age 1
• For women under 45 years, the approach is more selective: perform upper endoscopy only if upper GI symptoms are present, but always screen for celiac disease with antiendomysial antibodies and IgA levels 1
• All patients should be screened for celiac disease regardless of age, as this is a common cause of iron malabsorption 1

Laboratory Confirmation

• Serum ferritin is the most powerful test for iron deficiency, with a threshold of <45 mg/dL recommended for diagnosis 1
• Red cell indices (microcytosis and hypochromia) provide sensitive indication of iron deficiency in the absence of chronic disease or hemoglobinopathy 1
• The lower the hemoglobin, the more urgent the investigation, as this correlates with more serious underlying pathology 1

Essential History Points

• Quantify menstrual blood loss (menorrhagia is responsible for most IDA in premenopausal women, occurring in 5-10%) 1
• Assess dietary iron intake and consider nutritional consultation 1
• Review medication use, particularly NSAIDs which are common causes of IDA 1
• Evaluate for pregnancy and breastfeeding history 1

When to Perform Dual Investigation

• Do not stop at finding one lesion: dual pathology (significant bleeding sources in both upper and lower GI tracts) occurs in 1-10% of patients, particularly in older individuals 1
• Only advanced gastric cancer or confirmed celiac disease should deter lower GI investigation after upper endoscopy 1
• If celiac disease is found but the patient is >50 years, has marked anemia, or has significant family history of colorectal carcinoma, still perform lower GI investigation 1

Iron Replacement Therapy

First-Line Oral Treatment

• Begin with ferrous sulfate 200 mg once daily (containing 65 mg elemental iron), which is the simplest and most cost-effective option 1, 2
• Add vitamin C 500 mg with each iron dose to enhance absorption 1, 2
• Alternative ferrous salts (gluconate or fumarate) are equally effective if ferrous sulfate is not tolerated 1
• Liquid preparations may be necessary for patients with swallowing difficulties 1, 2

Optimal Dosing Strategy

• Alternate-day dosing is superior to daily dosing for doses ≥60 mg elemental iron, as daily dosing stimulates hepcidin elevation that persists 24 hours and reduces subsequent absorption by 35-45% 1, 3
• Give iron in the morning as a single dose, not in divided doses throughout the day, since circadian hepcidin increases are augmented by morning iron doses 3
• If one tablet daily is not tolerated, reduce to one tablet every other day rather than stopping treatment 1

Monitoring Response

• Hemoglobin should rise by 2 g/dL after 3-4 weeks of treatment 1, 2
• Continue oral iron for 3 months after hemoglobin normalizes to replenish iron stores 1, 2
• Monitor hemoglobin and ferritin every 3 months for the first year, then annually 2
• After restoration of iron stores, check blood count every 6 months initially to detect recurrent IDA 1

When Oral Iron Fails

Failure to respond is usually due to:

• Poor compliance (most common) 1
• Continued blood loss 1
• Malabsorption 1
• Misdiagnosis 1

Intravenous Iron Therapy

Indications for IV Iron

• Intolerance to at least two different oral iron preparations 1, 2
• Contraindication to oral iron 1
• Ineffective oral iron (ferritin levels do not improve after adequate trial) 2
• Conditions compromising oral iron absorption (inflammatory bowel disease with active inflammation, celiac disease not responding to gluten-free diet) 1, 2
• Unreliable compliance (consider earlier in complex patients) 2

IV Iron Administration

• Modern IV iron formulations can replace iron deficits with 1-2 infusions rather than multiple infusions 2
• True anaphylaxis is very rare; most reactions are complement activation-related pseudo-allergy (infusion reactions) 2
• The rise in hemoglobin is no quicker than with oral preparations, but IV iron avoids gastrointestinal side effects 1

Special Considerations for This Age Group

Premenopausal Women Specific Factors

• Menstrual loss, pregnancy, and breastfeeding are the usual causes in this population 1
• Women under 45 years without upper GI symptoms do not routinely need upper endoscopy, but should have celiac screening 1
• Colonic investigation in patients under 45 should only be done if there are specific indications 1

Red Flags Requiring Urgent Investigation

• Hemoglobin <10 g/dL in women suggests more serious disease requiring urgent investigation 1
• Involuntary weight loss, abdominal pain, or elevated CRP warrant small bowel investigation even after negative bidirectional endoscopy 4
• Family history of colorectal carcinoma 1

Common Pitfalls to Avoid

• Do not prescribe excessive daily doses (>200 mg elemental iron) as this increases side effects and paradoxically reduces absorption due to hepcidin elevation 1, 2
• Do not prematurely discontinue iron before stores are replenished (requires 3 months after Hb normalizes), as this leads to rapid recurrence 2
• Do not assume dietary insufficiency alone in women over 45 years—always investigate for GI pathology 1, 2
• Do not rely on faecal occult blood testing in the investigation of IDA, as it provides no benefit 1
• Do not defer iron replacement while awaiting investigations unless colonoscopy is imminent 1
• Recognize that continued blood loss will prevent response regardless of supplementation adequacy 2

Blood Transfusion

• Reserve packed red cell transfusions only for patients with or at risk of cardiovascular instability due to the degree of anemia 1
• Limited transfusion may occasionally be required to treat symptomatic IDA 1