Microcytic Anemia Flashcards
Variations in Hb
CBC – varies if prone, supine, seated, pregnant, night, or morning
Changes in Hb
Increased: increased WBC (WBC >50,000) from smoking, dehydration, and triglycerides >2000
Decreased: position, pregnancy, diurnal, race, females, and IV fluids
Hematocrit
Percentage of blood sample occupied by RBC’s
HCT = Hgb x 3
Falsely Abnormal MCV
Cold Agglutinins Hyperglycemia Reticulocytosis Leukocytosis Acute Hemolysis
Besides the CBC, What is the FIRST blood test that should be done in the evaluation of anemia?
Reticulocyte Count
> 3% = adequate response
Microcytosis Differenial Dx
Iron Deficiency
Thalassemia
Beta-Thalassemia: Elevated Hgb A2 or F
alpha Thalassemia diagnosis of exclusion
Anemia of Chronic Disease, though 75% pts it is normocytic
Sideroblastic anemia - rare
Lead poisoning – rare
Zinc Deficiency
Microcytosis
Due to Reduced Hemoglobin Synthesis
Several Causes Possible
From Defects in Iron acquisition or availability
Impaired Heme or Globin Synthesis- hemoglobinopathies
Iron Deficiency
MOST COMMON cause of microcytic anemia
Iron Studies: Iron Total Iron Binding Capacity (TIBC) Iron or Transferrin Saturation - Iron/TIBC Ferritin
Sites of Iron Loss: hemorrhagic telanglectasia, liver disease, angiodysplasia, Diverticular disease, IBD, hemmorhoids, esophageal ulcer/erosin/cancer/Mallory-Weiss tear/varices, peptic ulcer disease, Meckel’s diverticulum, colorectal cancer
Iron Deficiency: Females, Exercise, and Surgery
Average Iron Loss in Females:
1 to 3 mg per day
Pregnancy Associated with Increased Loss to 6 mg/day
Exercise Can Result in Iron Deficiency:
Gastrointestinal tract blood loss
Exercise-induced hemolysis
Increased levels of hepcidin
Bariatric Surgery
Iron Deficiency Anemia
In older males: LOOK FOR GI SOURCE
Think of how patient can be losing blood - find source of blood loss
Iron Therapy
Ferrous sulfate 325 mg PO per day
65 mg of elemental iron
May Be Able to Use Lower Doses
If Ferrous Sulfate NOT Tolerated Consider:
Ferrous Gluconate
Iron Drops
Lower Dose + Vitamin C / Cranberry Juice
Use Iron Until Iron Stores Normal
If Bleeding, May Take Months
Reticulocyte Count Should Increase in 7 to 10 days
Hemoglobin Should Increase Shortly After
2g/dL for each 3 week span
IV replacement (Parenteral) Anaphylaxis occurs a lot, so only use if cannot tolerate oral iron
Anemia of Chronic Inflammation
Anemia with either Normocytic or Microcytic Anemia
Normal or Increased Ferritin- anyone has a inflammatory process, ferritin is an acute phase reactant, so increases
May Have Known Underlying Disease
Hemoglobin rarely
Hepcidin
Synthesized in the Liver
Prevents parenchymal iron overload
Hepcidin reduces the quantity of circulating iron by preventing its exit from the cells, especially Enterocytes and Macrophages.
Hepcidin Binds to Ferroportin and induces Ferroportin internalization and degradation
Over production of hepcidin: low plasma iron = anemia of chronic disease
Low or No Hepcidin, Leads to Parenchymal/plasma Iron Overload = hemochromatosis
Mechanism of Anemia Inflammation
Normally, iron is absorbed in the GI tract and is delivered to transferrin for transport to the developing red cells, with any excess stored in hepatocytes.
In inflammatory states, decreased absorption of iron leads to reduced saturation of transferrin and impaired release of iron from storage, resulting in a lack of iron delivery to the developing red cells
These changes are mediated by hepcidin, which binds and inhibits ferroportin
Tx: Anemia of Chronic Disease
Treat Underlying Disease If Severe (measured by degree of symptoms), may need to transfuse or treat with Erythropoietin ... Be Careful with EPO, can cause strokes
Associated with:
Decreased Iron Uptake in the GI Track
Diminished Iron from Macrophages in the Bone Marrow
