Iron is an essential mineral that is needed to form hemoglobin, an oxygen carrying protein in red blood cells.
IDA is a condition in which the body lacks enough RBCs to transport oxygen-rich blood to body tissues.
The Iron Cycle
Iron from the food you eat is absorbed into the body by the cells that line the gastrointestinal tract; the body only absorbs a small fraction of the iron you ingest.
The iron is then released into the blood stream, where a protein called transferrin attaches to it and delivers the iron to the liver.
Iron is stored in the liver as ferritin and released as needed to make new red blood cells in the bone marrow.
When red blood cells are no longer able to function (after about 120 days in circulation), they are re-absorbed by the spleen.
Iron from these old cells can also be recycled by the body.
- Transferrin – plasma iron transporter protein. Carries less than 1% of total body iron.
- Ferritin – intracellular storage of iron.
- Hemosiderin – long term iron storage pool.
The Iron Cycle
Ferritin
- Multi-subunit protein
- Primarily intracellular
- Some in plasma
Hemosiderin
- Insoluble form of ferritin
- Visible microscopically
Pathogenesis of Iron Deficiency anemia
Once the stored iron is depleted, the body is able to make very few red blood cells.
If erythropoietin is present without sufficient iron, there is insufficient fuel for red blood cell production.
The red blood cells that the body is able to make are abnormal and do not have a normal hemoglobin-carrying capacity, as do normal blood cells.
Causes And Risk Factors
Blood loss – Blood contains iron within red blood cells. So if you lose blood, you lose some iron.
Women with heavy periods are at risk of iron deficiency anemia because they lose blood during menstruation.
Slow, chronic blood loss within the body such as from a peptic ulcer, or colorectal cancer can cause iron deficiency anemia.
Gastrointestinal bleeding can result from regular use of some over-the-counter pain relievers, especially aspirin.
Blood loss due to hookworm infestation.
A lack of iron in your diet. Your body regularly gets iron from the foods you eat.
If you consume too little iron, over time your body can become iron deficient. Examples of iron-rich foods include meat, eggs, leafy green vegetables and iron-fortified foods.
For proper growth and development, infants and children need iron from their diets, too.
An inability to absorb iron. Iron from food is absorbed into your bloodstream in your small intestine.
An intestinal disorder, such as celiac disease, which affects your intestine’s ability to absorb nutrients from digested food, can lead to iron deficiency anemia.
If part of your small intestine has been bypassed or removed surgically, that may affect your ability to absorb iron and other nutrients.
Pregnancy. Without iron supplementation, iron deficiency anemia occurs in many pregnant women because their iron stores need to serve their own increased blood volume as well as be a source of hemoglobin for the growing fetus.
Clinical Presentation
- Brittle nails
- Extreme Fatigue (tiredness)
- Chest pain or shortness of breath
- Pale skin
- Dizziness
- Headache
- Cold hands and feet
- Inflammation or soreness of your tongue
- Unusual cravings for non-nutritive substances, such as ice, dirt or starch (Pica)
- Poor appetite, especially in infants and children with iron deficiency anemia
- Rapid heartbeat
- Pounding or "whooshing" in the ears
What other Tests Will Be Done If Iron Deficiency Is Diagnosed?
Testing for blood in the stool (fecal occult blood test).
Looking for abnormalities in the gastrointestinal tract – upper and lower endoscopy (looking into the stomach, esophagus, or colon with a tube), capsule enteroscopy (swallowing a tiny camera that takes images of the gastrointestinal tract) or small bowel biopsy.
Testing the urine for blood or hemoglobin.
In women with abnormal or increased menstrual blood losses, a gynecologic evaluation that may include a pelvic ultrasound or uterine biopsy.
Treatment
Diet
- Meat: especially organ meats such as liver
- Poultry
- Fish
- Leafy green vegetables
- Legumes
- Iron-enriched pastas, grains, rice, and cereals
Iron Supplements
- Most people with iron deficiency need 150-200 mg per day of elemental iron (2 to 5 mg of iron per kilogram of body weight per day)
- MOA; During absorption oxygen combines with iron and is transported into the plasma portion of blood by binding to transferrin
- From there, iron and transferrin are used in the production of hemoglobin and myoglobin (helps your muscle cells store oxygen)
Intravenous Iron
- IV iron may be necessary to treat iron deficiency in patients who do not absorb iron well in the gastrointestinal tract, patients with severe iron deficiency or chronic blood loss, patients who are receiving supplemental erythropoietin (a hormone that stimulates blood production), or patients who cannot tolerate oral iron.
- IV iron comes in different preparations:
- Iron dextran
- Iron sucrose
- Ferric gluconate
- Large doses of iron can be given at one time when using iron dextran. Iron sucrose and ferric gluconate require more frequent doses spread over several weeks.
Blood Transfusions
- Red blood cell transfusions may be given to patients with severe iron-deficiency anemia who are actively bleeding or have significant symptoms such as chest pain, shortness of breath, or weakness.
- Transfusions are given to replace deficient red blood cells and will not completely correct the iron deficiency. Red blood cell transfusions will only provide temporary improvement.
