Anemia, Iron Deficiency
- Low serum iron associated with low hemoglobin (Hgb) or microcytic, hypochromic red blood cells (RBCs)
- Because normal Hgb varies with age and sex, anemia is defined as Hgb level 2 standard deviations below normal for age and sex (1).
- Onset acute (rapid blood loss) or chronic (slow blood loss, deficient iron intake, or poor absorption)
- Both low Hgb per RBC and fewer RBC in total lead to blood oxygen deficiency, which can have serious systemic consequences
- System(s) affected: hematologic, lymphatic, immunologic, cardiac, and gastrointestinal (GI) systems
- Iron deficiency anemia (IDA) is associated with increased hospitalization, morbidity, and mortality in older adults.
- Older patients with suspected IDA should undergo endoscopy to evaluate for occult GI malignancy.
- Risks for IDA in children include low birth weight, history of prematurity, lead exposure, low-income status, immigrant status, and drinking cow’s milk before 12 months of age.
- The U.S. Preventive Services Task Force (USPSTF) did not find sufficient evidence for screening low-risk infants; the Centers for Disease Control (CDC) recommends screening high-risk infants at 6 to 12 months of age, and the American Academy of Pediatrics (AAP) recommends universal screening at 12 months (1).
- Should screening be done, include both Hgb and ferritin.
- The USPSTF did not find sufficient evidence for screening pregnant women for IDA; the CDC recommends screening women for anemia at the first prenatal visit and giving low-dose iron to all pregnant women, whereas the American College of Obstetricians and Gynecologists (ACOG) recommends screening all pregnant women for IDA and treating those with IDA.
- Iron deficiency is the most common nutritional deficiency in the world, and IDA is the most common cause of anemia (50%).
- Predominant age: all ages but especially toddlers and menstruating and pregnant women
- Predominant sex: female
- Common in developing and developed countries
- Adults: men 2%, women 15–20% annually
- Infants and toddlers: 3–5% annually
- Pregnant patients: may be as high as 20% (1)
2 billion people worldwide
- Infants and children aged <12 years: 4–7%
- Men: 2–5%
- Menstruating women: 30%
Etiology and Pathophysiology
Depletion of iron stores leads to decrease in both reticulocyte count and production of Hgb. Causes:
- Blood loss (menses, GI bleeding, trauma)
- Poor iron intake
- Poor iron absorption (e.g., atrophic gastritis, postgastrectomy, celiac disease)
- Increased demand for iron (e.g., infancy, adolescence, pregnancy, breastfeeding)
- Premenopausal woman
- Frequent blood donor
- Pregnancy/lactation, young maternal age
- Strict vegan diet
- Use of NSAIDs
- Hospitalized with frequent blood draws
- Living in or visiting countries with endemic hookworm infection
- Consider screening asymptomatic pregnant women and high-risk children at 1 year of age (guidelines vary) (1)[C].
- Supplementation in asymptomatic children aged 6 to 12 months if at risk for IDA (e.g., malnutrition, abuse) (1),(2)
- Iron- and vitamin Crich diet for menstruating women
- Iron 30 mg/day for asymptomatic pregnant women (2)
Commonly Associated Conditions
- GI tract malignancy, peptic ulcer disease (PUD), Helicobacter pylori infection, irritable bowel disease
- Hookworm or other parasitic infestations
- Hyper metrorrhagia
- Obesity treated with gastric bypass surgery
- Medications such as NSAIDs or antacids
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