Blood Disorders Flashcards
Which statement about iron supplementation is FALSE?
a) Iron is poorly absorbed from enteric-coated tablets
b) The dosing of iron supplementation is slowly increased to minimize gastric upset
c) Elemental iron has few drug interactions
d) The target daily dose of elemental iron is 105-200mg per day
e) An equivalent strength of ferrous fumarate provides more elemental iron than ferrous gluconate
C. Oral iron preparations have many drug interactions, usually due to chelation. This reduces the absorption of both agents in the interaction and their administration should be separated by approximately 2 hours. Nonenteric-coated salts are preferred due to concerns with the effectiveness of enteric-coated preparations in releasing iron in the gastric environment. Gastrointestinal side effects are the main reasons for non-adherence and a graduated approach to dosing should be used to minimize these. The target daily dose is 105-200mg of elemental iron per day although in the elderly 15-50mg per day may be sufficient (page 1206, CTC, 7th edn). A 300mg tablet of ferrous fumarate provides 100mg of elemental iron; an equivalent tablet of ferrous gluconate provides only 35mg (Table 1, page 1213, CTC, 7th edn).
What is anemia?
a condition in which the number of red blood cells (and consequently oxygen-carrying capacity) is insufficient to meet the body’s physiologic needs.
What anemias respond to drugs?
- anemias due to iron, vit B12, folate deficiency
- anemias responding to erythropoietin therapy
Goals of therapy
Anemia
- alleviate symptoms
- restore normal or adequate Hb level
- improve quality of life
- prolong survival
According to WHO, when is anemia diagnosed using Hb levels?
men: <130 g/L
women (non-pregnant): <120 g/L
Investigations
Anemia
- hx for bleeding, jaundice, GI sx, heavy menses, family hx of anemia, medication use, diet, alcohol, comorbid conditions
- PE
- underlying causes: Deficiency in diet, conditions related to malabsorption, blood loss, LV dz/alcohol use, inherited defects in hemoglobin, suppression of bone marrow, def of erythropoeitin due to chronic kd dz or comorbind conditions (like hypothyroidism), chronic inflammatory diseases
- CBC: MCV (red cell size - too small <80 fL), RBCs. Peripheral blood smear. Ferritin, transferrin, vitamin b12.
How iron def anemia presents?
low MCV
low ferritin
low Hb
low transferrin sat
high transferrin
low hepcidin
How anemia of chronic disease presents?
high ferritin
high CRP
low to normal MCV
low Hb
low to normal transferrin sat
low to normal transferrin
How anemia of chronic disease and iron deficiency anemia present together?
high CRP
low Hb
normal to high ferritin
low to normal transferrin sat
low transferrin
low MCV
Dietary iron from animal sources (heme)
- liver
- lean red meat
- seafood (oysters, clams, tuna, salmon, sardines, shrimp)
Dietary iron from plant sources (non-heme)
- Legumes: Beans, peas, lentils, chickpeas, and soybeans
- Dark green vegetables: Spinach, broccoli, beet greens, collards, kale, and chard
- Nuts and seeds: A good source of non-heme iron
- Whole grains: Fortified breads and cereals, and wholemeal pasta
- Dried fruit: A good source of iron
- Quinoa: A pseudocereal that’s high in iron and gluten-free
- Tofu: A plant-based source of iron
non-heme is less bioavailable
Should you supplement iron intake with vitamin C?
May be beneficial to add Vit C for better absorption - studies are unclear. Makes no difference with oral iron supplementation.
Best way to treat anemia
pharmacological options work faster.
Pharma choices for iron supplementation
Anemia of Chronic Disease
- iron salts
- polysaccharide-iron complex
- heme iron polypeptides
- parenteral iron
iron salts
- there’s a variety of them with different amounts of elemental iron
- When given on empty stomach there is better absorption but side effects are more common (nausea and epigastric pain)
- recommend based on patient population, and whether if prevention or tx of iron def.
- taken on alternate days (instead of daily) increases absorption
- ongoing tx after iron storages are replenished depends on the cause of the anemia.
- in children and infants, works better than polysaccharide-iron complex
Polysaccharide-iron complex
- 150mg of elemental iron per capsule
- seems to be better tolerated than iron salts
Heme iron polypeptides
- 11mg of elemental iron/tablet
- better absorbed and tolerated than iron salts
- Dosage is 1 tab 3x/day as prevention
- no evidence is good for tx of anemia
- Made from hydrolysis of bovine hemoglobin - NOT FOR VEGANS, may matter to other patients.
Parenteral iron
For:
- reserved for patients with malabsorption
- intolerant of iron salts
- when large dosages are needed in a short period of time
Newer formulations have fewer AE (anaphylaxis)
- result in a more rapidd rise in Hb but needs to be received in the hospital or as outpatient
- consists of iron complexed with a CHO or salt
- high-dose can provide a full iron replacement in 1-2 infusions
- may reduce the need for RBC transfusion, but increases risk of infections.
How long it takes to see results with parenteral iron therapy
A reticulocyte response should be evident within 1 week of beginning iron therapy, with subsequent improvement in the Hb of about 10g/L every 7-10 days.
It is recommended that pregnant patients meet the dietary requirements of iron through diet and/or supplementation to prevent the development of iron deficiency during pregnancy and postpartum. T/F
True
Why do iron requirement increases during pregnancy?
They increase due to the expansion of maternal red cell mass and growth of the fetus and placenta.
Are treatments of iron def in pregnant patients the same as in non-pregnant patients?
Yes. There is no teratogenic effects of iron supplementation on the fetus.
Does iron passes into breast milk?
Yes. It is an important source of dietary iron for the developing infant.
The amount of iron in breast milk is influenced significantly by maternal iron status. T/F
False. It is not.
