Anemia Overview - Johns Flashcards
What is the definition of anemia?
- Operationally defined as reduction in one or more of the major RBC measurements:
- –Hemoglobin concentration, hematocrit, or RBC count
- –All of these are concentration measures
- Anemia is a CONCENTRATION ISSU - ration of plasma to RBCs
With ___ _____ you won’t be anemic.
acute bleeding
There are two questions with anemia:
- Is it caused by production problems?
2. Is it caused by survival/destruction problems?
What is the key test for anemia?
Reticulocyte count!!
-Reticulocytes are early precursors of RBCs. The majority of RBCs are in the bone marrow but some are in the blood/periphery
What are the two main approaches (not mutually exclusive) for looking at anemia?
- Biologic or kinetic approach
2. Morphology
How do you make a reticulocyte count useful?
The reticulocyte count must be adjusted for the patient’s hematocrit (erythrocyte volume function). When hematocrit is lower, reticulocytes are released earlier from the marrow - so one can adjust for this phenomenon.
What does reticulocyte count tell us (kinetic approach)?
- Increased reticulocytes (greater than 2-3% or 100,000 mm^3 total) are seen in blood loss and hemolytic processes, although up to 25% of hemolytic anemia will present with a normal reticulocyte count due to immune destruction of red cell precursors.
- Reticulocyte counts are most helpful if extremely low (
What does reticulocyte count tell us (kinetic approach)?
- Increased reticulocytes (greater than 2-3% or 100,000 mm^3 total) are seen in blood loss and hemolytic processes, although up to 25% of hemolytic anemia will present with a normal reticulocyte count due to immune destruction of red cell precursors.
- Reticulocyte counts are most helpful if extremely low (
What is normal hemoglobin in men and women?
Men - 13-16
Women - 11.5-14
What is normocytic normochromic anemia?
-Reticulocyte count - Index
What is micro or macrocytic anemia?
-Reticulocyte count - Index
What is hemolysis/hemorrage anemia?
- Reticulocyte count - Index >/= 2.5
- Hemolysis/hemorrhage: blood loss, intravascular hemolysis, metabolic defect, membrane abnormality, hemoglobinopathy, immune destruction, fragmentation hemolysis
What does a normal reticulocyte count indicate?
What does a high reticulocyte count indicate?
Normal - production problem
High - problem with destruction (cross out blood loss - especially acute)
Whites the morphological approach of investigating anemia?
Big vs. little (measurement)
How do you determine RBC size?
MCV
What is normal MCV?
80-100
What causes MCV of 80-100 (normocytic)?
- Anemia of chronic disease
- Mixed deficiencies
- Renal failure
What causes MCV > 100 (macrocytic - over production)?
- B12, Folic acid deficiency (B12 and folic acid go together like ham & eggs!)
- Drugs that impair DNA synthesis (AZT, chemotherapy, alcohol, azathioprine)
What causes MCV
- Iron deficiency
- Thalassemia trait
- Anemai of chronic disease (30-40%)
- Sideroblastic anemias
What does CBC tell you?
Complete blood count
- Tells you your white blood cell count - differential (WBC)
- Hemoglobin
- Platelets
- Indices - various measures of red cell size: MCV - mean corpuscular volume, MCHC
What is the etiology of Macrocytic Anemia?
B12/Folate Deficiency
- Anemia: Vitamin B12 and folate are needed for DNA synthesis deoxyuridate to thymidylate, including RBC precursors
- Deficiency: B12 - dietary intake (rare), decreased gastric secretion of intrinsic factor, Folate - poor dietary intake +/- EtOH, malabsorption, increased demand (pregnancy, hemolytic anemias)
How to diagnose macrocytic anemia?
- Smear: Macrocytic (High MCV) RBCs, +/- hypersegmented neutrophils, +/- modest neutropenia (low count neutrophils), but . . .
- –B12
- Low serum B12, elevated serum methylmalonic acid levels
- Anti-IF Abs, Schilling test (?), PA accounts for 75%
- –Folate
- Serum folate level– can normalize with a single good meal
What causes MCV
- Iron deficiency
- Thalassemia trait
- Anemia of chronic disease (30-40%)
- Sideroblastic anemias
What causes MCV
- Iron deficiency
- Thalassemia trait
- Anemia of chronic disease (30-40%)
- Sideroblastic anemias
How to treat B12/Folate Deficiency?
B12 deficiency: B12 1 mg/month IM
What can cobalamin/Vitamin B12 deficiency cause?
Neurological problems
-Subacute combined degeneration of the dorsal and lateral spinal columns
When do you have increased iron requirements?
- Blood loss
- GI disorder (esophageal varices, hemorrhoids)
- Extensive and prolonged menstruation
- Chronic blood donations
- Rapid growth in body size between 2 and 36 months of age
- Pregnancy and lactation
When do you have an inadequate iron supply?
- Poor nutritional intake in children
- Malabsorption
- Gastric bypass surgery for ulcers or obesity
- Achlorhydria from gastritis or drug therapy
- Severe malabsorption (for example, celiac disease [nontropical sprue])
How to test for iron deficiency?
- Decreased hemoglobin
- Microcytic MCV
- Decreased serum iron
- Increased or normal TIBC (total iron binding capacity)
- Decreased iron saturation
- –Serum Fe/TIBC
What are Thalassemias?
- Genetic defects in hemoglobin synthesis!
- –Dec. synthesis of one of the 2 globin chains (alph or beta)
- –Imbalance of globin chain synthesis leads to depression of hemoglobin production and precipitation of excess globin (toxic)
- –
What are Thalassemias?
- Genetic defects in hemoglobin synthesis!
- –Dec. synthesis of one of the 2 globin chains (alph or beta)
- –Imbalance of globin chain synthesis leads to depression of hemoglobin production and precipitation of excess globin (toxic)
- –“ineffective erythropoiesis”
- –Ranges in severity from asymptomatic to incompatible with life (hydrous fetalis)
- –Found in people of African, Asian, and Mediterranean heritage
How do you diagnose Thalassemias?
- Smear: microcytic/hypochromic, misshapen RBCs
- Beta-thal will have an abnormal Hgb electrophoresis (Inc. HbA2, Inc. HbF)
- The more severe alpha-thal syndromes can have HbH inclusions in RBCs
- Fe stores are usually elevated
How do you treat Thalassemias?
Mild: None
Severe: RBC transfusions + Fe chelation, Stem cell transplants
What is anemia of chronic disease?
- Normocytic (normal red cell size)
- You NEED a chronic disease (usually inflammatory or infectious)
What is the pathogenesis of anemia of chronic disease?
- Cytokines are produced (IFN-gamma, IL-1beta, TNF-alpha,etc.) and cause:
- –Decreased EPO production
- –Suppression of erythroid progenitors
- –Blockade of reticuloendothelial iron release
What does anemia of chronic disease look like (lab panel)?
- Microcytic or normocytic anemia
- Decreased serum iron
- Decreased serum TIBC (total iron binding capacity)
- Normal Fe/TIBC percentage
- Normal or increased ferritin (stores and releases iron in a controlled fashion)
What is ferratin?
Measures your total body iron stores!
- If you’re iron deficient, this number will be decreased
- If you have anemia of chronic disease - your fourteen number will be normal
What are sideroblastic anemias?
- Sideroblasts are produced instead of healthy red blood cells
- Heterogenous grouping of anemias defined by presence of ringed sideroblasts in the BM
What are the etiologies of sideroblastic anemias?
- Hereditary (rare), type of porphyria
- Myelodysplasia
- EtOH
- Drugs (INH, Chloramphenicol)
Auto-immune conditions can cause. . .
hemoglobin and platelets to decrease
What should you do after an MCV test if its normal?
Bone marrow biopsy to diagnose
-If MCV normal, you need to determine, is there a chronic disease?
What should you do if you find anemia?
-If MCV is high, could be B12, folate or hemolytic anemia (if you have tons of reticulocytes -> but we always do retriculocyte count first)
What are the general principles of anemia?
- It’s a sign, not a sieges
- Anemias are a dynamic process
- It’s never normal to be anemic
- The diagnosis of iron deficiency anemia mandates further work-up
