What is anemia and its management?

Anemia: Definition, Types, and Management

Anemia is a condition characterized by decreased hemoglobin concentration or red blood cell count that requires comprehensive evaluation and targeted treatment based on the underlying cause. This presentation will cover the definition, types, diagnostic approach, and management strategies for anemia.

Definition and Prevalence

• Anemia is defined by the World Health Organization as hemoglobin levels below 13 g/dL in men, below 12 g/dL in non-pregnant women, and below 11 g/dL in pregnant women 1
• It affects approximately one-third of the world's population, with iron deficiency accounting for about half of all cases 2
• Iron deficiency anemia (IDA) occurs in 2-5% of adult men and post-menopausal women in developed countries 1

Types of Anemia

Iron Deficiency Anemia

• Most common type of anemia worldwide 2
• Characterized by microcytosis (low MCV), low serum ferritin, and low transferrin saturation 1
• Common causes:
  • Gastrointestinal blood loss in men and post-menopausal women 1
  • Menstrual blood loss in pre-menopausal women 1
  • Malabsorption (especially celiac disease) 1
  • Poor dietary intake 1

Anemia of Chronic Disease (ACD)

• Second most common type of anemia globally 3
• Associated with chronic inflammation, autoimmune diseases, cancer, and kidney failure 3
• Features include normal or low MCV, low iron, low transferrin, but increased ferritin 3
• Mediated by inflammatory cytokines and hepcidin, which blocks iron absorption and utilization 1, 3

Other Types

• Vitamin B12 or folate deficiency (macrocytic anemia) 1, 4
• Hemolytic anemia (increased reticulocytes, elevated LDH, decreased haptoglobin) 1
• Genetic disorders (thalassemias, sickle cell disease) 5
• Anemia due to chronic kidney disease 6

Diagnostic Approach

Initial Assessment

• Complete blood count with red cell indices (MCV, MCH, RDW) 1
• Reticulocyte count to assess bone marrow response 1
• Serum ferritin (most powerful test for iron deficiency) 1
• Transferrin saturation 1
• C-reactive protein (to assess inflammation) 1

Additional Testing Based on Initial Results

• For microcytic anemia:

  • Serum ferritin <12 μg/dL is diagnostic of iron deficiency 1
  • Consider thalassemia if red cell count is elevated 1
  • In inflammatory states, ferritin may be elevated despite iron deficiency 1

• For macrocytic anemia:

  • Vitamin B12 and folate levels 1, 4
  • Consider medication effects, alcohol use, or thyroid dysfunction 1

• For normocytic anemia:

  • Evaluate for chronic disease, kidney disease, or hemolysis 1
  • Check haptoglobin, LDH, and bilirubin if hemolysis is suspected 1

Management Strategies

Iron Deficiency Anemia

• Identify and treat the underlying cause 1
• Iron supplementation:
  • Oral iron is first-line therapy 1
  • Parenteral iron when oral preparations are not tolerated 1
  • For inflammatory conditions, IV iron may be more effective due to hepcidin-mediated blockade of oral absorption 1
• Gastrointestinal investigation:
  • Upper GI endoscopy with small bowel biopsy 1
  • Colonoscopy or barium enema 1
  • Especially important in men and post-menopausal women to exclude malignancy 1

Anemia of Chronic Disease

• Treat the underlying inflammatory condition 1, 3
• Iron therapy if concurrent iron deficiency exists 1
• Consider erythropoietin therapy in specific situations:
  • Chronic kidney disease 6
  • HIV patients on zidovudine 6
  • Cancer patients on chemotherapy 6
  • Warning: ESAs increase risk of death, MI, stroke, and thromboembolism when targeting hemoglobin >11 g/dL 6

Vitamin B12 Deficiency

• Intramuscular vitamin B12 injections 4
• Caution: Folic acid supplementation may mask B12 deficiency symptoms while allowing neurological damage to progress 4
• Monthly injections required for life in pernicious anemia 4

Special Considerations

Anemia in Heart Failure

• Prevalence ranges from 6-70% in heart failure patients 1
• Associated with increased mortality (hazard ratio 2.1) and hospitalization rates 1
• Evaluation algorithm:
  • Check iron studies even in non-anemic patients 1
  • Consider iron deficiency when ferritin <100 ng/mL or ferritin 100-300 ng/mL with transferrin saturation <20% 1
  • Evaluate renal function, thyroid function, and inflammatory markers 1
• Treatment:
  • IV iron has shown benefits in heart failure patients with iron deficiency 1

Anemia in Inflammatory Bowel Disease

• Regular monitoring recommended due to high prevalence 1
• Minimum workup includes CBC, CRP, and serum ferritin 1
• Consider both iron deficiency and anemia of chronic disease as potential causes 1

Pitfalls to Avoid

• Failing to investigate the cause of iron deficiency anemia in men and post-menopausal women 1
• Misinterpreting ferritin levels in inflammatory states 1
• Using folic acid without addressing B12 deficiency, which can mask anemia while allowing neurological damage 4
• Targeting hemoglobin levels >11 g/dL with erythropoietin therapy, which increases cardiovascular risks 6
• Overlooking functional iron deficiency in patients with normal ferritin but low transferrin saturation 1