HEME 02-05: Iron Deficiency Anemia Flashcards
1
Q
What are the signs and symptoms specific to iron deficiency anemia?
A
- glossitis
- koilonychia (indented nails)
2
Q
What are the 4 types of iron studies/labs?
A
- serum iron
- ferritin
- total iron binding capacity (TIBC)
- transferrin saturation (TSAT)
3
Q
What is serum iron?
A
concentration of iron bound to transferrin
4
Q
Serum Iron Levels
A
- only interpreted in conjunction with TIBC
- transferrin normally ⅓ saturated by iron
- level remains within lower limit of normal until iron stores are depleted
- diurnal variation – higher in morning, lower in afternoon
- decreased by infection and inflammation
5
Q
What is ferritin?
A
iron-storage protein
- important test when screening for IDA
6
Q
Ferritin Levels
A
- < 30 mcg/L in adults
- < 20 mcg/L in children
- < 100 mcg/L in chronic inflammation
- influenced by inflammation, infection, pregnancy, or obesity – must interpret with context
7
Q
What is total iron binding capacity (TIBC)?
A
indirect measure of total iron-binding capacity of serum transferrin
8
Q
Total Iron Binding Capacity (TIBC) Levels
A
- does not fluctuate over hours or days
- usually high when body iron stores are low
- may be low in setting of infection, malignancy, inflammation, liver disease, and uremia
9
Q
What is transferrin saturation (TSAT)?
A
serum iron level divided by TIBC
10
Q
Transferrin Saturation (TSAT) Levels
A
- low values may indicate IDA
- low serum values may also be present in inflammatory disorders
11
Q
Iron Studies Levels in IDA
A
- low iron
- low ferritin
- high TIBC
12
Q
Iron Studies Levels in ACD with IDA
A
- low/normal iron
- low/normal ferritin
- low TIBC
13
Q
What are the recommended daily intakes (RDI) for iron?
A
- adult males: 8 mg
- postmenopausal females: 8 mg
- menstruating females: 18 mg
- children require more due to growth-related increases in blood volume
- pregnant women require more due to fetal development
14
Q
How is iron (Fe) best absorbed?
A
as heme iron (Fe+2)
- primarily in duodenum (stomach acidic), and less in jejunum
- meat, poultry, fish
15
Q
What factors impact iron absorption?
A
- polyphenols: (tea, coffee) bind iron and decrease non-heme iron absorption
- ascorbic acid: (vitamin C) increase absorption of non-heme iron
- calcium: inhibits absorption of both heme and non-heme iron
- gastrectomy or achlorhydria: decreased iron absorption
16
Q
What is the general recommended daily dose of iron supplementation?
A
100 mg of elemental iron
- dose depends on patient’s ability to tolerate
- tolerance of iron salts improves with small initial dose and gradual escalation to full dose
17
Q
Ferrous Gluconate (1)
A
300 mg tab (35 mg elemental)
- 1 tab BID-TID (max 5 tab/day)
- 70-105 mg of elemental iron daily
18
Q
Ferrous Sulfate (2)
A
300 mg tab (60 mg elemental)
- 1 tab BID-TID
- 120-180 mg of elemental iron daily
30 mg/mL suspension (6 mg elemental/mL)
- 10 mL BID-TID
- 120-180 mg of elemental iron daily
19
Q
Ferrous Fumarate (3)
A
300 mg tab/cap (100 mg elemental)
- 1 cap OD-BID
- 100-200 mg elemental iron daily
200 mg tab (65.7 mg elemental)
- 1 tab BID-TID
- 131.4-197.1 mg of elemental iron daily
60 mg/mL suspension (20 mg elemental/mL)
- 5 mL OD-BID
- 100-200 mg of elemental iron daily
20
Q
Polysaccharide Iron Complex (FeraMAX) (2)
A
150 mg cap (150 mg elemental)
- 1 cap OD
- 150 mg of elemental iron daily
60 mg/tsp powder (60 mg elemental)
- 1 tsp BID-TID
- 120-180 mg of elemental iron daily
21
Q
Heme Iron Polypeptide (Proferrin) (1)
A
398 mg tablet (11 mg elemental)
- 1 tab OD-TID
- 11-33 mg of elemental iron daily
22
Q
What are some counselling points for iron salt formulations (gluconate, sulfate, fumarate)?
A
- take on empty stomach to ↑ absorption (at least 1 hr before or 2 hr after eating) – needs acid in stomach to get absorbed
- absorption may ↓ if taking antacids or medications that reduce stomach acid
- suspension formulations may stain teeth – can prevent by drinking with straw or mixing with water or juice
23
Q
What are some counselling points for polysaccharide iron complex (FeraMAX)?
A
- take with or w/o food – does not need acid in stomach to get absorbed, therefore good choice if taking medications that reduce stomach acid
- can mix capsule content into water or sprinkle over soft food
- tasteless
24
Q
What are some counselling points for heme iron polypeptide (Proferrin)?
A
- > bioavailability than non-heme
- take with or w/o food
- contains animal/cow products
25
What is the general recommendation for duration of therapy of iron supplementation?
3-6 months, or up to 3 months after Hb has been reached
- Hb will correct within 2-4 months if appropriate iron dosages are taken as prescribed and underlying cause of iron deficiency is corrected
26
What drugs decrease iron absorption?
separate administration by 2 hr
- H2 antagonists
- PPIs
- Al-, Mg-, and Ca2+-containing antacids
- tetracycline and doxycycline
- cholestyramine
27
How can gastric side effects/intolerance be minimized?
initiate therapy with 1 tab of ferrous sulfate 300 mg/day with food, then gradually shift away from meals to improve absorption
28
Formulation Selection Considerations
- marginal differences in efficacy between daily dosing and every-other-day dosing
- lower single daily doses and every-other-day dosing of iron can improve absorption and tolerability
- divided doses increased hepcidin compared with daily dosing and failed to improve absorption
29
Oral Iron Therapy Monitoring
- frequency depends on severity of anemia, underlying cause of deficiency, clinical impact on patient
- Hb should increase by 10-20 g/L by 4 weeks
- may take up to 3-6 months to replenish iron stores
- re-check ferritin 3-6 months after normalization of Hb
- consider adherence, ongoing bleeding, malabsorption, or alternate diagnosis if Hb/ferritin not normal
30
RBC Transfusions
- avoid transfusing RBCs for IDA without hemodynamic stability
- restricted for cardiovascular compromise and/or debilitating symptoms
- Hb < 70 g/L
31
Iron Sucrose (Venofer)
- 20 mg Fe/mL
- 100-300 mg IV per session, given as total cumulative dose of 1000 mg over 14 days
32
Ferric Gluconate Complex (Ferrlecit)
- 12.5 mg Fe/mL
- 125 mg IV per dose, up to 1000 mg over 8 sessions
33
Ferric Derisomaltose (Monoferric)
- 100 mg Fe/mL
HgB ≥ 100 g/L
- 50-70 kg: 1000 mg x 1 dose
- ≥ 70 kg: 1500 mg x 1 dose
HgB < 100 g/L
- 50-70 kg: 1500 mg x 1 dose
- ≥ 70 kg: 2000 mg x 1 dose
34
Iron Dextran Complex (Infufer)
- 50 mg Fe/mL
- based on body weight and Hb
- IV intermittent, maximum 1000 mg/day
- IM up to 100 mg Fe per site, maximum 250 mg/day
35
What are the adverse effects of IV iron therapy?
- headache, dizziness
- angioedema
- bronchospasm, wheezing, chest pain
- hypertension, hypotension (rapid infusion), tachycardia, bradycardia, arrhythmias, chest pain
- nausea, vomiting, abdominal pain, diarrhea, urine discolouration
- local site reaction (thrombophlebitis), arthralgias, back pain, myalgias, weakness, urticarial, pruritus
- anaphylaxis, leukocytosis (elevated WBC)
36
Monitoring for IV Iron Therapy
- maximum Hb response to IV iron usually within 2-3 weeks of last administered dose
- check iron stores 4 weeks post-therapy for repletion – reinvestigate cause if not replete
- check iron stores after 3 months to ensure deficiency does not recur – reinvestigate and/or refer if recurs
- low dose maintenance may be required for patients with ongoing needs – menses, dietary, growth spurts
37
What are the hematologic changes in pregnancy that result in physiologic anemia? (4)
- physiologic anemia
- leukocytosis
- mild thrombocytopenia
- ↑ procoagulant factor / ↓ fibrinolysis
38
Anemia in Pregnancy
Hb Levels
WHO:
- Hgb < 110 g/L at any time during pregnancy
CDC:
- Hgb < 110 g/L during first trimester
- Hgb < 105 g/L in second and third trimester
39
What lab value is an unreliable marker of iron deficiency in pregnancy?
mean corpuscular volume (MCV)
- low MCV is not specific for IDA
40
How does TIBC change in pregnancy?
increase
41
What is hepcidin?
master regulator of systemic iron bioavailability – currently being evaluated as biomarker in pregnancy
- decreases as pregnancy progresses
- pregnant women with undetectable serum hepcidin transfer more maternally-ingested iron to their fetus
42
What is adequate to assess iron status in majority of pregnant women?
Hb, % of transferrin saturation, and plasma ferritin
43
How long should iron supplementation continue postpartum?
until 6 weeks postpartum
44
What are the maternal iron requirements?
- for fetus and placenta: 300-350 mg
- for expansion of maternal RBC mass: 500 mg
- associated with blood loss during labour and delivery: 250 mg
- requirement for iron increases gradually from 0.8 mg per day in first trimester to 7.5 mg per day in third
45
What does the CDC and WHO recommend for iron supplementation in pregnancy?
- CDC: all pregnant women should begin 30 mg/day iron supplement at first prenatal visit
- WHO: 60 mg/day for all pregnant women
46
Should oral or IV iron therapy be used in pregnancy?
- treat iron deficiency with oral iron in first trimester
- reserve IV iron for after 13th week – evidence shows use of IV iron to improve Hb more rapidly
47
What is the recommended dose for oral iron therapy in pregnancy?
60-200 mg/day of elemental iron
- generally aim for 100 mg to start
48
When is iron absorption best in pregnancy?
best when dosing was restricted to lower doses and less frequent administration
- 40-80 mg of iron no more than once daily
- higher or more frequent doses of iron raised circulating hepcidin levels and reduced subsequent fractional iron absorption
- every other day dosing results in greater iron absorption compared with daily dosing
49
What is the recommended dose for oral iron therapy in pregnancy?
- 30 mg elemental iron PO daily
- provided by most prenatal vitamins
50
What are the risk factors for IDA in children prior to 6 months?
full-term infants have iron stores to last up until age 6 months
prior to 6 months:
- maternal IDA
- fetal
- maternal hemorrhage
- prematurity
growth and lack of adequate intake
51
What are the risk factors for IDA in children?
- low socioeconomic status
- high-risk population – Indigenous communities
- early introduction of cow’s milk or excessive cow’s milk intake
- prolonged exclusive breastfeeding
- diet low in iron
- medical conditions – medications that interfere with iron absorption, malabsorption, blood loss
52
What is anemia (Hb levels, ferritin) in children?
- 6 months to 5 years: HgB < 110 g/L
- 5-12 years: HgB < 115 g/L
- 12-15 years: HgB < 120 g/L
- serum ferritin < 15 ug/L
53
What are the signs and symptoms of IDA in children?
- often asymptomatic
- lethargy
- irritability
- poor feeding
- pallor
54
How can IDA be prevented in children?
- breastfeeding
- iron-fortified formula
- discourage cow's milk until 12 months – then max 500-750 mL/day
- iron rich foods
55
What is the recommended dose for IDA treatment for children?
3-6 mg/kg/day of elemental iron in divided doses
56
IDA in Children
Ferrous Sulfate (2)
suspension: 30 mg/mL
- 6 mg Fe/mL
- 250, 500 mL bottles
drops: 75 mg/mL
- 15 mg Fe/mL
- 50 mL bottles
57
IDA in Children
Ferrous Fumarate (1)
suspension: 60 mg/mL
- 20 mg Fe/mL
- 100 mL bottles
58
What is the recommended dose for IDA treatment in school-aged children?
60 mg PO daily
59
What is the recommended dose for IDA treatment in adolescents?
- adolescent male: 120 mg PO daily
- adolescent female: no routine iron supplementation required – encourage dietary measures, screen every 5-10 years or annually if risk factors, treat as adult non-pregnant female
