Microcytic anemia

Microcytic anemia (Microcytic anemia)

1) Disease description (causes and pathophysiology, major symptoms)

• Definition and pathophysiology
  • Refers to hypochromic microcytic anemia with a decreased mean corpuscular volume (MCV) (generally MCV < 80 fL).
  • Major pathophysiological mechanisms: decreased heme and hemoglobin synthesis due to impaired iron utilization (iron deficiency or impaired iron transport/mobilization), heme-synthesis enzyme defects (sideroblastic anemia), or decreased globin synthesis (thalassemia) and others.
• Major causes
  • Iron deficiency: inadequate dietary intake, gastrointestinal bleeding (peptic ulcer, tumors, hemorrhoids, etc.), heavy menstruation, pregnancy, etc.
  • Anemia associated with chronic disease (inflammatory cytokines inhibit iron mobilization)
  • Thalassemia (α/β-thalassemia; genetic globin-synthesis defect)
  • Sideroblastic anemia (impaired heme synthesis; drug-related, toxic, or genetic causes)
  • Lead poisoning (inhibition of heme biosynthesis and hemolysis)
• Major symptoms
  • Fatigue, lethargy, pallor (skin and mucous membranes), shortness of breath, palpitations, dizziness, headache
  • In chronic cases: nail deformities (spoon-shaped nails), hepatosplenomegaly (especially in thalassemia), delayed growth/learning (in children)
  • In acute/severe cases, chest pain, syncope, and symptoms of heart failure may occur

2) Treatment methods and precautions

• Standard treatment according to the cause after diagnosis
  • Iron-deficiency anemia
    • Oral iron (e.g., a recommended effective elemental iron dose of 100–200 mg/day in the form of iron chloride or iron sulfate; consult the attending physician regarding the dosage)
    • Intravenous iron when there are problems with gastrointestinal absorption, severe anemia, or poor tolerance of oral iron (formulations include iron sucrose and ferric carboxymaltose)
    • Treatment of the source of bleeding (medical/surgical), and management of heavy menstruation
  • Anemia due to chronic disease
    • Priority is given to treating the underlying inflammation, infection, or tumor
    • Depending on the case, intravenous iron or erythropoietin (ESA) may be considered
  • Thalassemia
    • Mild: observation or replacement treatment if needed
    • Moderate to severe: regular transfusion therapy (according to symptoms and the Hb target)
    • Patients receiving repeated transfusions: iron chelation therapy to prevent iron overload (e.g., deferoxamine, deferiprone, deferasirox)
    • For confirmed severe forms, hematopoietic stem cell transplantation may offer definitive treatment; genetic counseling is recommended
  • Sideroblastic anemia (congenital/acquired)
    • Discontinue causative medications, pyridoxine (vitamin B6) treatment (effective in some patients), and treatment of the bone marrow and underlying disease
  • Lead poisoning
    • Eliminate lead exposure and use chelation therapy if necessary
• General treatment guidelines and monitoring
  • When administering oral iron, continue for at least 2–3 months and confirm improvement in hemoglobin and iron-storage markers (ferritin)
  • Transfusion may be considered for symptomatic anemia or when there is cardiac or respiratory risk (individualized)
  • In patients receiving repeated transfusions, regularly monitor iron levels and tissue damage (heart, liver, and endocrine organs) and provide chelation therapy
• Lifestyle management and diet
  • Iron-rich foods are recommended (red meat, liver, chicken, fish, legumes, and green and yellow vegetables)
  • Vitamin C promotes iron absorption, while calcium, tea, and coffee inhibit absorption; consider the timing of iron supplementation
  • Regular testing and supplementation should be considered for high-risk groups such as pregnant women, vegetarians, and athletes
• Precautions (warnings)
  • Gastrointestinal problems (abdominal pain, constipation, nausea) may occur when taking iron supplements — adjust the method of administration or change the formulation if necessary
  • Excessive iron supplementation is dangerous in children, so store it carefully
  • Excess iron (iron overload) after transfusions may cause heart and liver damage — long-term follow-up is necessary

3) Checklist before an outpatient visit (items to prepare and points to check before consultation)

• Items/documents to prepare or bring

  • List of all medications and supplements currently being taken (including dosage and administration times)
  • Previous test results (most recent CBC, ferritin, serum iron, TIBC, hemoglobin electrophoresis, etc.)
  • History of previous transfusions (number and timing), surgery and bleeding history, and whether pregnant
  • Timing of symptom onset and progression (degree of fatigue, shortness of breath during exercise, presence or absence of syncope or chest pain)
  • Family history (hereditary anemia or thalassemia)

• Items useful to record before the consultation

  • Changes in menstrual flow (whether heavy menstruation is present), gastrointestinal symptoms (bloody stool or suspected gastrointestinal bleeding), and weight changes
  • Eating habits (whether vegetarian, amount of iron intake), alcohol use, smoking, and occupational exposure to hazardous substances (such as lead)

• Example questions (for patients to record themselves)

  • When did the fatigue and pallor begin?
  • Have you recently had gastrointestinal bleeding, frequent nosebleeds, or heavy menstruation?
  • Does anyone in your family have a similar history of anemia?

4) Examples of general questions to ask the doctor

• “What is the exact cause of my anemia? What additional tests are needed?”
• “What type of medication (iron supplement) should I take, and for how long? What are the side effects?”
• “When can I expect my blood test results to improve? What is the target Hb level for treatment?”
• “Am I in a situation that requires a transfusion, and what are the risks and benefits of transfusion?”
• “Do I need regular monitoring for iron overload or additional treatment?”

5) Examples of disease-specific questions

• (For patients suspected of having iron deficiency) “What ferritin and TIBC results on a blood test confirm iron deficiency? Do I need additional tests to check for gastrointestinal bleeding?”
• (For patients suspected of having or diagnosed with thalassemia) “Do I need hemoglobin electrophoresis or genetic testing? Do you recommend family testing or genetic counseling? What will the regular transfusion and chelation plan be?”

Note: The information above is general medical information, and its application may vary depending on the individual’s condition. Actual diagnosis and treatment plans should be decided in consultation with the attending physician.