Macrocytic Anemia Disorders

Macrocytic Anemia

• Def:
  • Anemia with MCV > 100
  • RBCs are bigger than normal
    
  • Most commonly due to folate or vitamin B12 deficiency (megaloblastic anemia)
• Causes:
  • – Abnormal DNA metabolism
    
  • – Shift to immature RBCs
    
  • – Primary bone marrow disorders
    
  • – Lipid RBC membrane abnormalities
    
  • – Unknown/mixed mechanism
  • – alcoholism, liver disease, and drugs

Megaloblastic anemia

• Def:
  • hypersegmented neutrophils
    
  • megaloblastic change in rapidly dividing epithelial cells
    
  • *Macrocytic, normochromic, hypersegmented neutrophils**
    
  • *marrow- megaloblastic erythroid hyperplasia*
• Path:
  • -impaired DNA SYN
    
• Causes:
  • – Vitamin B12 deficiency
    
  • – Folic acid deficiency
    
  • – Copper deficiency
    
  • – Certain medications

Vitamin B12 Deficiency

• Clinical Manifestations:
  • – Pancytopenia 
  • – Megaloblastic anemia 
  • – Peripheral neuropathy 
  • – Paresthesia/dysthesia 
  • – Irritability
  • – Cognitive impairment
  • – Depression
  • – Possible increased r/o MI, CVA 
• Labs:
  • macrocytic anemia with hypersegmented neutrophils, glossitis
    
  • subacute combined degeneration of the spinal cord
    
  • decreased serum B12
    
  • INCREASED serum homocysteine
    
  • increased methylmalonic acid

Folate deficiency

• Clinical Manifestations:
  • – Pancytopenia
    
  • – Megaloblastic anemia
    
  • – Peripheral neuropathy
    
  • – Paresthesia/dysesthesia
    
  • – Cognitive impairment
    
  • – Depression
    
  • – Dermatitis
    
  • – Glossitis/angular cheilitis
• Labs:
  • macrocytic anemia and hypersegmented neutrophils
    
  • glossitis
    
  • decreased serum folate
    
  • increased serum homocysteine
    
  • normal methylmalonic acid

Copper deficiency

• Clinical Manifestations:
  • – Pancytopenia
    
  • – Megaloblastic anemia
    
  • – Osteoporosis
    
  • – Gray hair formation
• Labs:
  • – ovalocytes
    
  • – hypersegmented neutrophils
    
  • – normal folate
    
  • – normal vitamin B12