Anemia Flashcards
Anemia Definition
- When blood has a reduced capacity to delivery oxygen
- reduced Hct, Hgb, or RBC count -> at least 1 of these = anemia
- Males: Hgb<130 g/L
- Females: Hgb <120g/L
Anemia triad
- Blood loss
- RBC destruction
- Inadequate production of normal RBCs
T or F: Anemia is a disease
False - Anemia is NOT a disease itself but a characteristic of underlying disorders
Conditions leading to Anemia Triad
- Blood loss – heavy periods, ulcers, surgery, pregnancy
- RBC destruction – kidney disease w/ dialysis, hemolytic anemia
- Inadequate RBC – diet low in iron/folic acid/B12, sickle cell anemia, lack of EPO, pregnancy
Acute vs. Chronic Anemia Symptoms
Acute:
* Tachycardia, palpitations
* Hypotension, light-headedness
* Dyspnea (shortness of breath)
Chronic:
* Weakness, fatigue
* HA, vertigo, faintness
* Sensitivity to cold, pallor, loss skin tone
When Hgb <90g/L:
* Tongue pain, smooth tongue, pica, pagophagia
What Hormone Triggers RBC production?
- Erythropoietin (EPO)
Where does Erythropoiesis Occur?
- bone marrow
Normal Lifespan of RBC
- 120 days
At what stages of differentiation is EPO important?
- Erythroid burst-forming unit -> Erythroid colony-forming unit
- Erythroid colony-forming unit -> Proerythroblast
What do Reticulocytes tell us about Bone Marrow?
- High RC - BM working well
- Low RC - BM NOT working well
Importance of EPO
5 functions
- Stimulate stem cells to differentiate to proerythroblasts
- Increase rate of mitosis at each cell maturation stage
- Prevent apoptosis of erythroid precursor cells
- Increase release of reticulocytes into circulation
- Increase Hgb formation
EPO Feedback Loop
- Kidneys sense low O2-carrying capacity
- Secrete more EPO
- EPO stimulates erythropoiesis in BM
- Increased O2-carrying capacity w/ more RBC
- Ends feedback loop
Most common nutritional deficiency in developing and developed countries
Iron Deficiency Anemia
Iron deficiency anemia results from 3 things:
- Decreased iron intake or absorption
- Increased iron demans
- Increased iron loss
True or False: Nonheme iron is 3 times more absorbable than heme iron
False
Heme iron is 3x more absorbable than nonheme iron
Examples of heme iron/ examples of nonheme iron
Heme iron: meat, fish, poultry
Nonheme iron: vegetables, fruits, beans, nuts, grain products
Steps of iron absorption
Normal diet contains 10-15mg iron in the non-absorbable ferric (Fe3+) state
Stomach acid reduces the iron to the absorbable ferrous (Fe2+) state
Where in the body is ferrous iron primarily absorbed
Duodenum and to a lesser extent the jejunum
What % of ingested iron is absorbed?
Only 10% BUT deficiency states of increased erythropoiesis can increase absorption to 20-30%
What is ferritin?
Iron stores
Example of iron absorption enhancer
Vitamin C enhances absorption minimally (200mg of vit C only increases absorption of 30mg og elemnetal iron by about 10%)
Examples of iron absorption inhibitors
Tea and coffee consumed in large amounts with a meal (polyphenols can binds iron and decrease non-heme iron absorption)
Calcium (reduces heme and nonheme absorption)
Recommended Daily Iron Intake in…
-Adult males/post-menopausal females
-Menstruating and lactating females
-Pregnancy
-Children
-10 mg/day in adult males/post-menopausal females
-15 mg/day in menstruating and lactating females
-30 mg/day in pregnancy
-6-10 mg/day in children (age-dependent)
What are our 2 goals of iron deficiency anemia treatment?
1) Replenish iron stores
2) Identify what caused the iron deficiency in the first place
(both equally as important)
True or False: Enteric coated products and slow-release products are recommended for most patients with IDA
False
Since an acid medium is required for reduction to the ferrous state and
What is the treatment for IDA?
Oral iron
How should we advise patients to take oral iron?
Best taken on an empty stomach as food interferes with absorption, but may be impractical due to constipation, N/V/D, stomach upset, other intolerances
Dose for oral iron
100-200mg elemental iron per day, usually 1-3 divided doses, for 3-6 months after anemia is resolved
Why do we give oral iron for 3-6 months after anemia is resolved?
To build iron stores
What are the 3 traditional iron salts for oral iron treatment?
Ferrous sulfate
Ferrous gluconate
Ferrous fumarate
How many oxygens can 1 Hgb hold?
4
What is Transferrin?
- transport protein in plasma
- delivers iron to BM
What are the 3 non-traditional salts for oral iron treatment?
Iron polysaccharide complex (also known as feramax)
Heme iron polypeptide (also known as proferin)
Iron bisglycinate
Which iron tablet is the only one connected to heme?
Proferin (heme iron polypeptide)
Name some strategies to improve oral iron tolerability
-Increase dosing interval
-Switching formualtions with lower amounts of elemental iron
-Start at lower dose, titrate up
-Switch from tablet to liquid, easier titration
-Dietary modificaitons
-Try newer iron formulations
-Can switch to IV iron
What is the Hepcidin response?
Our body’s mechanism to control how much iron we absorb from our diet
How does Hepcidin work?
It binds to ferroportin leading to degradation of the iron transport channel
What is Ferritin?
- body storage iron
What is Hemosiderin?
- less available storage iron form
RES
- Reticuloendothelial system
- transferrin delivers extra iron to storage sites: liver, marrow, spleen
Drug interactions with oral iron
Levodopa (chelates with iron)
Methyldopa (decreases efficacy of methyldopa)
Levothyroxine (decreases efficacy of levothyroxine)
Oral iron doses (hint include if its ODB or not)
Ferrous sulfate 75mg/mL oral liquid (ODB), 300mg tabs
Ferrous gluconate 300mg tabs (ODB)
Ferrous fumarate 300mg caps, 60mg/mL oral liquid (ODB)
Iron polysaccharide complex caps, tabs, liquid powder (not on ODB)
Proferrin tabs (heme iron) (not on ODB)
Iron bisglycinate tabs (not on ODB)
Who is parenteral iron reserved for?
Patients who:
-Are unable to tolerate or absorb oral iron
-Inadequate response to oral iron
-Have extensive chronic blood loss or extreme deficit in iron stores who cannot be maintained with oral iron alone
-Need rapid correction of anemia
-Also used in some patients with severe chronic kidney disease (esp if on hemodialysis), some patients with cancer
Name the 4 types of parental iron treatment
- Iron dextran (infufer, dexiron)
- Iron sucrose (venofer)
- Sodium ferric gluconate (Ferrlecti)
- Iron isomaltoside (Monoferric)
How is Iron dextrain (infufer, dexiron) given?
IM - very painful, possible tissue staining
IV - hypersensitivity and anaphylactic reactions possible
How is iron sucrose (venofer) given?
- IV only, less likely to cause hypersensitivity rxs
- Test dose not required, but consider if the patient has a history of multiple drug allergies
- Officially indicated for treatment of IDA in CKD patients only
How is sodium ferric gluconate (ferrlecit) given?
- IV only
- Test dose not required, but consider if the patient has a history of multiple drug allergies
- Officially indicated for treatment of IDA in hemodialysis patients receiving supplemental EPO
How is iron isomaltoside (monoferric) given?
What is special about it?
- IV only
- Test dose not required
- Benefit is that a full dose up to 1500mg or 20mg iron/kg can be given in one session, unlike other available products
- Officially indicated for any patient with IDA intolerant to oral therapy
True or False: It is recommended that a patient either be on oral iron or IV iron, not both
True
No point on being on both oral iron and IV iron at the same time
Why do we need to make sure that parenteral iron is not infused too quickly?
Transferrin binding sites can be overloaded, resulting in excess free iron in the bloodstream that can interfere with neutrophil function, perpetuate inflammatory reactions, and compromise active treatment of a coexisting infection
What is a risk of all parenteral iron products?
All carry a risk for anaphylactoid reactions and infusion reactions
What is Ganzoni Formula used for?
Helps decide how much iron the patient actually needs
What is the Ganzoni Formula?
Iron needed (mg) = BW (kg) x target Hb-Actual Hb (g/dL) x 2.4 + iron for iron stores (mg)
3 Types of IV iron reactions
- Severe/anaphylactoid reactions
- Fishbane reactions
- Isolated mild/moderate reactions