Vitamin B9 deficiency

Background

  • Also known as folate, folic acid
  • Necessary for normal erythropoiesis, purine and thymidylate synthesis, amino acids metabolism, and histidine metabolism
  • Found in most fruits and vegetables
  • Recommended daily intake: 400 mcg or 500-600mcg if pregnant or lactating
  • Total body stores of folate enough to supply requirements for 2–3 mo

Causes

Clinical Features

  • Signs/symptoms of anemia which may be severe
  • Glossitis
  • Vague GI disturbances (e.g. anorexia, diarrhea)
  • No neurologic features (unlike B12 deficiency)

Differential Diagnosis

Anemia

RBC Loss

RBC consumption (Destruction/hemolytic)

Impaired Production (Hypochromic/microcytic)

  • Iron deficiency
  • Anemia of chronic disease
  • Thalassemia
  • Sideroblastic anemia

Aplastic/myelodysplastic (normocytic)

  • Marrow failure
  • Chemicals (e.g. ETOH)
  • Radiation
  • Infection (HIV, parvo)

Megaloblastic (macrocytic)

Evaluation

  • CBC
    • Macrocytic anemia (MCV>100 fL)
    • RDW high
    • Hypersegmented neutrophils
  • Red blood cell folate level < 150 ng/mL

Management

  • Folate: up to 1mg IV/IM or PO daily
    • Maintenance: 0.4mg/day PO (non-pregnant/lactating) or 0.8mg/day PO (pregnant or lactating)

Disposition

See Also

External Links

References