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Macrocytic Anemia
- Macrocytic anemias produce strange dysfunctional blood cells. This will result in some hemolysis and progress to splenic dysfunction as the spleen becomes overloaded.
- Howell-Jolly bodies are DNA remnants seen with a macrocytic anemia or a damaged spleen. You will find them in B12 deficiency anemia, folate deficient anemia, sickle cell anemia and celiac disease.
- Retic count will be low. The body doesn’t have enough supplies to produce new cells.
- Megaloblastic anemia is caused by a problem with DNA synthesis during red blood cell production. The most common cause of this is folic acid or B12 deficiency
Folic Acid Deficiency
Causes
- Decreased intake likely secondary to alcohol abuse
- Decreased absorption – intake of folic acid antagonist (Methotrexate)
- Pregnancy
- Hemolytic anemia
Clinic Presentation
- Sore/swollen tongue
- GI issues: diarrhea
- Mouth and peptic ulcers
- Symptoms of anemia
- No Neurologic findings
Labs
- CBC
- Low H&H
- Elevated MCV
- Low retic count
- Peripheral blood smear
- Macro-ovalocytes
- Big oval RBCs
- Not seen under conditions
- Howell-Jolly bodies
- A RBC that still carries a small portion of DNA. Cells of this type would be removed by a functioning spleen
- Hypersegmented neutrophils
- Folate level <150
- B12 is normal
Treatment
- Folic acid supplement
- Reversal of causative issue
B12 Deficiency
Causes
- Pernicious anemia- inability of GI tract to absorb B12 due to a missing transport protein called intrinsic factor
- 1 cause of B12 deficiency
- Most often caused by an autoimmune response.
- May be a complication of gastric surgery – intrinsic factor is produced in the stomach
- Vegan diet – animal products contain B12 – meat, dairy, poultry
- Bowel surgery – B12 is absorbed in the terminal ileum so surgically removing this part of the intestine causes malabsorption.
- Crohn’s disease – terminal ileum may not be functioning
Clinical presentation
- Neurological findings
- Stocking glove paresthesias
- Ataxia
- Poor coordination of movement (think patient looks intoxicated)
- Loss of fine touch
- Dementia
- Depression
- Symptoms of anemia
Labs
- CBC
- Low H&H
- Elevated MCV
- Low retic count
- Peripheral blood smear
- Macro-ovalocytes
- Big oval RBCs
- Not seen under conditions
- Howell-Jolly bodies
- A RBC that still carries a small portion of DNA. Cells of this type would be removed by a functioning spleen
- Hypersegmented neutrophils
- Macro-ovalocytes
- Indirect bilirubin elevated secondary to hemolysis
- Serum B12 is usually very low.
- Antibodies to gastric parietal cells and intrinsic factor
Treatment
- Treat underlying cause if possible
- Intramuscular B12
- High dose of oral B12 will allow some to pass through the small intestine by passive diffusion without intrinsic factor
- Oral intrinsic factor may be given, but if the patient has intrinsic factor antibodies this method will not be effective.
- Neurological symptoms which are treated within the first 6 months to do well. Starting treatment after 6 months of symptoms may result in permanent damage.
Focal points
- Macro-ovalocytes = Folic acid or B12 deficiency
- Howell-Jolly bodies should make you think of B12 or folate deficient anemia, sickle cell anemia and celiac disease
- Stocking glove paresthesias = B12 deficiency or diabetic neuropathy
