How to manage a patient with iron deficiency anemia, possible folate deficiency, and severe anemia?

Laboratory Interpretation and Management

These labs demonstrate severe iron deficiency anemia with possible concurrent folate deficiency requiring immediate iron replacement, investigation of the underlying cause (particularly GI blood loss), and consideration of folate supplementation.

Laboratory Interpretation

Severe Iron Deficiency Anemia

• Hemoglobin 8.3 g/dL represents severe anemia requiring urgent investigation regardless of sex, as lower hemoglobin levels correlate with more serious underlying pathology 1
• MCV 70 fL (microcytosis), MCH 18.8 pg, and MCHC 27.0 g/dL (hypochromia) are classic findings of iron deficiency, with hypochromia being a particularly reliable marker 2
• Iron 15 μg/dL and transferrin saturation 3% are severely reduced (normal TSAT >30%), confirming absolute iron deficiency 1
• RDW 15.7% is elevated, which can indicate combined deficiency states (iron plus folate/B12) 1
• Platelet count 469 (reactive thrombocytosis) is commonly seen with iron deficiency and chronic blood loss 3

Folate Deficiency Consideration

• Folate <2.0 ng/mL suggests concurrent folate deficiency, which can mask microcytosis and explain the elevated RDW in a combined deficiency state 1
• Combined iron and folate deficiency may produce a mixed picture where the MCV could be higher than expected for pure iron deficiency 4

Immediate Management Algorithm

Step 1: Iron Replacement (First Priority)

• Start oral iron supplementation immediately with 65 mg elemental iron daily as first-line therapy 2
• Monitor hemoglobin response within 2 weeks; expect ≥10 g/L rise if compliant and absorbing 2
• Consider intravenous iron if oral iron is not tolerated, malabsorption is suspected, or losses exceed oral replacement capacity 1, 3
• Continue iron therapy until hemoglobin normalizes AND iron stores are repleted (ferritin >100 ng/mL) 1, 3

Step 2: Folate Replacement

• Initiate folic acid 1 mg daily given the documented folate deficiency 5
• This is particularly important as combined deficiency can impair erythropoietic response to iron alone 4

Step 3: Investigate Underlying Cause (Critical)

For men and post-menopausal women with iron deficiency anemia, GI blood loss is the most common cause and exclusion of GI malignancy is of prime concern 1

Mandatory Investigations:

• Upper endoscopy (OGD) with small bowel biopsies to screen for coeliac disease and evaluate for gastric cancer, peptic ulcer disease, or angiodysplasia 1
• Colonoscopy (preferred over CT colonography or barium enema) to exclude colorectal cancer, polyps, or inflammatory bowel disease 1
• Coeliac disease screening should be performed in all patients, as malabsorption is a common cause after GI blood loss 1

Additional Considerations:

• Obtain detailed medication history, particularly NSAID use, which is a common cause of occult GI bleeding 1
• Dietary history to identify iron-deficient diets, though this should not preclude full GI investigation 1
• For pre-menopausal women, menstrual history is essential, but GI investigation should still be considered based on clinical judgment 1

Step 4: Transfusion Consideration

• Blood transfusion should be reserved for patients with or at risk of cardiovascular instability due to the degree of anemia 1
• At hemoglobin 8.3 g/dL, assess for symptoms of cardiovascular compromise (chest pain, severe dyspnea, tachycardia, hypotension) before deciding on transfusion 1

Critical Pitfalls to Avoid

• Do not assume dietary deficiency or menstruation as the sole cause without investigation—even mild anemia may indicate serious underlying pathology including malignancy 1, 2
• Do not delay GI investigation—only advanced gastric cancer or confirmed coeliac disease on upper endoscopy should deter lower GI investigation 1
• Do not stop at finding one lesion—dual pathology (upper and lower GI sources) occurs in 1-10% of patients, especially in older individuals 1
• Do not rely on fecal occult blood testing—it has no benefit in the investigation of iron deficiency anemia 1
• Do not forget to check vitamin B12 in addition to folate, as B12 deficiency can coexist and requires different management 1, 5
• Monitor response to therapy—failure to respond to oral iron within 4-8 weeks suggests malabsorption, ongoing blood loss, or incorrect diagnosis requiring further investigation 2, 6