Anemia Flashcards
What is anemia?
Reduction of volume of red blood cells (RBC) or hemoglobin (Hgb) concentration
Reduced oxygen-carrying capacity of blood
Usually a sign of an underlying pathology
What is the pathophysiology involved with anemia?
Inadequate production of RBC
Nutritional deficiencies
Excessive destruction of RBC (too much lysis)
Blood loss
What are the three types of anemia?
Microcytic- cells are too small
Normocytic
Macrocytic- cells are too big
What are the causes of microcytic anemia?
Iron deficiency Sickle cell Heavy metal poisoning Chronic disease Thalasemia
What are the causes of normocytic anemia?
Blood loss Hemolysis Aplastic anemia Marrow failure Chronic disease Renal failure Endocrine disorders Acute infection
What are the causes of macrocytic anemia?
B12 deficiency
Folic acid def.
Alcoholism
What are the signs of anemia?
Tachycardia
Pallor
Decreased mental acuity
Increased intensity of cardiac murmurs
What are the symptoms of anemia?
Decreased exercise tolerance Fatigue Dizziness Irritability Weakness Vertigo Shortness of breath Chest Pain
What are the physical exam findings of anemia?
May have no symptoms Pale conjunctiva, mucous membranes, nail beds Postural hypotension, tachycardia Jaundice (with hemolysis) Neurologic findings (B12)
What are the lab parameters associated with anemia?
CBC: Hgb, Hct, platelets, WBC RBC indices: MCV, MCHC, RDW Iron studies: iron, TIBC, ferritin, percent transferrin saturation Reticulocyte count Folic acid/B12 level Bilirubin Coombs test
What is the most common cause if microcytic anemia?
Iron deficiency
How do thalassemias cause microcytic anemia?
Deficiency in production of α or βchain of Hgb
Autosomal recessive genetic disorder
Trait (1 copy of gene) protective against malaria
Most common in those of Mediterranean descent
How do you treat thalassemias that cause microcytic anemia?
Those who are autosomal recessive are supported with frequent, lifelong blood transfusions, iron chelation therapy, splenectomy
Only curative treatment is hematopoietic stem cell transplant
How does sickle cell disease cause microcytic anemia?
Production of abnormal Hgbβchain
Autosomal recessive genetic disorder
Trait (1 copy of gene) protective against malaria
Most common in those of African descent
Those who are autosomal recessive have HgbS – abnormal hemoglobin that can cause RBC to change to sickled shape after release of O2
Cells are weakened by constant sickling & un-sickling, and can lyse, leading to anemia
Who is considered at high risk for development of or developing complications from iron deficiency anemia?
Children < 2 years
Menstruating adolescent females
Pregnant women
> 65 years old
What is the pathophysiology of iron deficiency anemia?
Hgb is O2-binding protein in RBC
Iron is incorporated into Hgb and directly binds O2
Reduced iron supply leads to reduced production of Hgb
RBC are deficient of Hgb, therefore
Hypochromic
Microcytic
What dietary sources can iron be found in?
Meats Fortified cereals Grains Legumes Green leafy vegetables
What from is most dietary iron?
Ferric from (Fe3+)
What form of iron is best absorbed?
Ferrous form (Fe2+) Acid reduces ferric to ferrous (Have patients drink orange juice with iron so that its more absorbable.)
Where is iron absorbed? Is heme or non-heme iron absorbed more?
Absorbed mainly in duodenum via direct uptake
Heme iron 3x more absorbable than non-heme iron
Heme found in meat, fish, poultry
Non-heme found in fortified cereals, beans, leafy green vegetables
What compounds can reduce iron absorption by forming complexes?
Phytates from vegetables/grains, polyphenols from tea/coffee, and caclcium
What are the inadequate intake causes of iron deficiency?
Vegetarians/vegans
What are the impaired absorption causes of iron deficiency?
Chelation
Gastrectomy
Enteritis
Inflammatory bowel disease
What are the increased requirement causes of iron deficiency?
Infancy
Pregnant/lactating
What are the blood loss causes of iron deficiency?
Menstruation
Trauma
GI bleeding- ulcer, hemorrhoids, tumor, alcohol, steroids/NSAIDS
What are the iron deficiency anemia symptoms
Decreased exercise tolerance Fatigue Dizziness Irritability Weakness Vertigo Shortness of breath Chest Pain PICA IF VERY SEVERE DEFICIENCY
What are the lab findings associated with iron deficiency anemia?
↓ Hgb ↓ Hct ↓ MCV ↑ RDW ↓ Iron ↓ Ferritin ↑ TIBC ↓ Fe: TIBC ratio
How do you treat iron deficiency anemia?
Treat underlying disease Correct iron deficiency Dietary Encourage intake of foods high in iron Heme iron is easiest to absorb May not be able to meet needs if Vegetarian/vegan Problems with iron absorption Oral Supplementation
What are the dietary sources of heme iron?
Chicken liver Oysters Beef Turkey (dark>light meat) Chicken (dark>light meat)
What are the dietary sources of non-heme iron?
Cereal/oatmeal, fortified Soybeans Other legumes Tofu Spinach
What are the available iron replacement products?
FERROUS SULFATE FERROUS GLUCONATE Ferrous Fumarate Polysaccharide iron complex Carbonyl Iron
What should you watch for with iron replacement?
Amounts of elemental iron
Iron (FERROUS SULFATE, FERROUS GLUCONATE, Ferrous Fumarate, Polysaccharide iron complex, Carbonyl Iron)- administration
Can cause substantial GI intolerance
Give in divided doses (2 – 3 times daily)
Start with smaller doses to improve tolerance, then escalate
Best absorbed without food
Can take with food if GI intolerance occurs
Try to make GI a little more acidic by taking with OJ
Keep out of reach of children!
Risk of toxicity
Iron (FERROUS SULFATE, FERROUS GLUCONATE, Ferrous Fumarate, Polysaccharide iron complex, Carbonyl Iron)- adverse effects
Nausea/vomiting
Constipation- huge issue
Dark stool- make sure they know this
Iron (FERROUS SULFATE, FERROUS GLUCONATE, Ferrous Fumarate, Polysaccharide iron complex, Carbonyl Iron)- interactions
- Antacids- often have calcium which chelate with iron and will make it a clump that comes right out
- Tetracycline antibiotics
- Histamine-2 antagonists
- Proton pump inhibitors- change acidity
- Cholestyramine- screws up absorption of all
- Fiber
Iron (FERROUS SULFATE, FERROUS GLUCONATE, Ferrous Fumarate, Polysaccharide iron complex, Carbonyl Iron)- Goals and monitoring
Normalize Hgb
Responds in ~ 3 weeks
Should rise 2 – 4 g/dL in this time
Resolution within 1-2 months
Replete iron stores
Takes 3 - 6 months
Supplement iron for 3 – 6 months
Iron (FERROUS SULFATE, FERROUS GLUCONATE, Ferrous Fumarate, Polysaccharide iron complex, Carbonyl Iron)- failure of therapy
If Hgb rises < 2g/dL after 3 weeks of treatment
Reasons Poor patient compliance Inability to absorb iron Incorrect diagnosis Persistent bleeding
When is parenteral iron used?
Evidence of iron malabsorption
Intolerance of oral iron
Long-term noncompliance
Significant blood loss and refusal of transfusions
What are the parenteral iron drugs?
IRON SUCROSE
IRON DEXTRAN
Sodium Ferric Gluconate
Parenteral iron (Iron sucrose, Iron dextran, Sodium Ferric Gluconate)- Adverse effects
Flushing Hypotension Fever/chills Myalgia ANAPHYLAXIS- BLACK BOX WARNING Iron overload
Parenteral iron (Iron sucrose, Iron dextran, Sodium Ferric Gluconate)- monitoring
Weekly Hgb Hct Ferritin Transferrin saturation Monthly Serum iron (these take a long time to build up)
What are the causes of megaloblastic macrocytic anemias?
Vitamin B12 (cyanocobalamin) deficiency Folate deficiency Abnormal utilization of B12 or folate
What are the causes of non-megaloblastic macrocytic anemias?
Alcohol abuse
What is the pathophysiology of macrocytic anemias?
–Abnormal DNA synthesis in developing erythrocyte
B12 & folate are required cofactors
–Resulting RBC are macrocytic and immature
–Hypercellular bone marrow, full of “–blast” progenitor cells
Especially erythroid line
