What is the management approach for a patient with anemia?

Management of Anemia

Begin iron replacement therapy immediately in all patients with confirmed anemia to correct hemoglobin levels and replenish body stores, while simultaneously investigating the underlying cause through targeted diagnostic evaluation. 1, 2

Diagnostic Workup

Initial Laboratory Assessment

• Obtain complete iron studies immediately: serum ferritin, transferrin saturation (TSAT), and total iron-binding capacity (TIBC) to confirm iron deficiency 2
• Measure reticulocyte count to distinguish regenerative from non-regenerative anemia and assess bone marrow response 2
• Check inflammatory markers (CRP, ESR) to identify anemia of chronic disease, which may coexist with iron deficiency 2
• Assess renal function with creatinine to exclude renal causes 2

Diagnostic Thresholds

• Anemia is defined as hemoglobin <13 g/dL in men and <12 g/dL in women 1
• Iron deficiency is confirmed by ferritin <100 μg/L and TSAT <20% 1
• In inflammatory conditions, iron deficiency may exist with ferritin between 45-100 μg/dL, requiring confirmatory testing with soluble transferrin receptor or reticulocyte hemoglobin equivalent 1

Classification by Red Cell Indices

• Microcytic anemia (MCV <80 fL): Perform iron profile workup as above 1
• Normocytic anemia (MCV 80-100 fL): Evaluate creatinine and inflammatory markers 1
• Macrocytic anemia (MCV >100 fL): Check TSH, folate, and vitamin B12 levels 1

Gastrointestinal Investigation

Who Requires GI Evaluation

• All postmenopausal women and all men with confirmed iron deficiency anemia must undergo upper and lower GI investigation unless there is documented significant non-GI blood loss 1, 2
• Men with hemoglobin <12 g/dL and postmenopausal women with hemoglobin <10 g/dL require urgent investigation due to higher likelihood of serious underlying pathology 1, 2

Comprehensive Endoscopic Evaluation

• Perform upper endoscopy (OGD) with duodenal biopsies to evaluate for peptic ulcer disease, gastritis, celiac disease, and upper GI malignancy 2
• Perform colonoscopy to exclude colorectal pathology, as it has advantages over CT colonography for investigating iron deficiency anemia 1, 2
• Complete both upper and lower GI investigations even if one reveals pathology, as dual pathology occurs in 10-15% of patients 1, 2
• Screen all patients for celiac disease with tissue transglutaminase antibody, particularly premenopausal women 1, 2
• Test for Helicobacter pylori and eradicate if present in patients with recurrent iron deficiency anemia and normal endoscopic findings 1

Premenopausal Women

• Screen for celiac disease in all premenopausal women with iron deficiency anemia 1
• Base decisions for upper and lower GI investigations on clinical judgment, considering menstrual history, family history of colorectal cancer, and severity of anemia 1

Iron Replacement Therapy

Oral Iron Supplementation

• Prescribe oral iron as first-line treatment: ferrous sulfate 325 mg (65 mg elemental iron) two to three times daily 2
• Continue treatment for three months after hemoglobin correction to adequately replenish iron stores 2
• Monitor response to therapy: failure to respond warrants further investigation for malabsorption or ongoing blood loss 1

Intravenous Iron Therapy

• Use parenteral iron when oral preparations are not tolerated or ineffective 1, 2
• Administer IV iron in inflammatory bowel disease patients with active inflammation and compromised absorption 1
• Consider IV iron in portal hypertensive gastropathy patients with ongoing bleeding who do not respond to oral iron 1
• Use IV iron in celiac disease if oral supplementation fails to improve iron stores 1

Special Populations

Critical Care Patients

• Implement phlebotomy reduction strategies to prevent iatrogenic anemia 1
• Adopt restrictive transfusion thresholds and single-unit transfusion policy 1
• Consider erythropoietin treatment, especially after trauma, in the absence of contraindications 1
• Avoid routine iron therapy except in the context of erythropoietin treatment 1

Inflammatory Bowel Disease

• Determine whether iron deficiency is from inadequate intake/absorption or blood loss 1
• Treat active inflammation effectively to enhance iron absorption and reduce iron depletion 1
• Use IV iron therapy in patients with active inflammation and compromised absorption 1

Heart Failure Patients

• Evaluate iron status in all anemic heart failure patients, as 50-70% have iron deficiency 1
• Consider IV iron therapy as it improves functional capacity and quality of life in this population 1

Blood Transfusion Strategy

Restrictive Transfusion Approach

• Reserve blood transfusions for patients with or at risk of cardiovascular instability due to severe anemia 1, 2
• Use a restrictive transfusion threshold of hemoglobin <7-8 g/dL in stable, non-cardiac patients 1
• Transfuse only the minimum number of RBC units required to relieve severe symptoms or return to safe hemoglobin range 1

Urgent Transfusion Indications

• Any patient with hemoglobin <7.5 g/dL or hemodynamic instability requires immediate intervention 2
• Patients with cardiovascular symptoms (chest pain, severe dyspnea, tachycardia) may require transfusion at higher thresholds 1

Critical Red Flags Requiring Expedited Evaluation

• Alarm symptoms: weight loss, dysphagia, melena, or hematochezia mandate urgent GI evaluation 2
• Severe anemia: hemoglobin <7.5 g/dL requires immediate assessment and intervention 2
• Hemodynamic instability: tachycardia, hypotension, or signs of tissue hypoperfusion 2
• Failure to respond to appropriate iron therapy within 4-6 weeks suggests ongoing blood loss, malabsorption, or alternative diagnosis 1

Common Pitfalls to Avoid

• Do not rely on faecal occult blood testing in the investigation of iron deficiency anemia, as it provides no diagnostic benefit 1
• Do not stop investigation after finding one source of bleeding, as dual pathology is common 1, 2
• Do not use ferritin alone in inflammatory conditions to diagnose iron deficiency; add transferrin saturation or other confirmatory tests 1
• Do not delay investigation in men or postmenopausal women assuming dietary deficiency, as GI malignancy must be excluded 1, 2