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Iron Deficiency Anemia 缺铁性贫血/ Reading & Sharing

The most commonly encountered cause of nutritional anemia is iron-deficiency anemia,  is found in infants, the elderly, and middle-aged women. Iron is a nutrient found in food which when ingested is absorbed in the duodenum and upper jejunum. From the digestive system iron is then transported to: 1) the bone marrow for hemoglobin synthesis, 2) Needy tissues such as muscle for myoglobin synthesis, and 3) Reticuloendothelial cells in the Liver to be stored as ferritin and hemosiderin until released for use in the bone marrow to form new RBCs (Eckman et al, 2013).

Iron is an essential part of hemoglobin, myoglobin, cytochrome, and peroxidases due to its role in the structure of heme; hemoglobin stores about 1.5-2.5 g of iron. Iron absorption occurs in the duodenum and is regulated strictly to avoid toxic iron accumulation or deficiency. Oxidation and reduction reactions are necessary for iron to be absorbed, transported, and metabolized. The daily need of an adult is about one milligram of iron, which is satisfied by the daily intake of iron salts and the intake of up to about 10-20 mg iron. The type of food, for example, meat, is an important factor affecting the bioavailability of iron.  Other factors include promoters, acidity increases iron absorption or inhibitors (Alaliwi et al., 2018).

 

Pathophysiology:

Iron deficiency anemia is a condition that takes place in the blood. It is when the total body iron is decreased below the normal level which are 65 to 176 mcg/dL for men and 50 to 170 mcg/dL for females. When these levels are low it directly affects the hemoglobin synthesis. The red blood cells will appear smaller and pale related to low iron levels. Iron deficiency anemia is not an isolated disease and the diagnosis must not only focus on the intake of iron but consider contributing factors such as the age, gender, menopausal status, and altitude or geographical of patients that affects patient’s hemoglobin levels.

Malabsorption is one of the causes of iron deficiency anemia in postmenopausal women. Malabsorption is the inability of the gastrointestinal tract to absorb ingested nutrients and micronutrients. Various diseases such as celiac disease, inflammatory bowel disease, and Whipple’s disease, to name a few may lead to malabsorption of essential nutrients such as iron, vitamin B12, folates, and vitamin A. Malabsorption diseases such as celiac disease, IBD, and H. pylori gastritis are frequently associated with iron deficiency anemia (Qamar et., al, 2015).

Anemia effects one quarter of the world’s population. In anemia your body does not have sufficient red blood cells (RBC’s).  RBC’s contain hemoglobin, which is an iron-rich protein that carries oxygen to the rest of your body for essential cell functioning. In anemia fewer RBC’s means less circulating hemoglobin and less iron. Causes of anemia (low number of RBC’s) include:

  • Blood loss from ~ hemorrhage from trauma, surgical hemorrhage, gastrointestinal diseases / bleeds, excessive NSAID use, heavy menstrual bleeding
  • Sickle cell disease.

(NIH,2014).

Iron deficiency anemia occurs when the supply or stores of iron in the body are insufficient for the demand of needed iron, an imbalance (NIH, 2014). Besides the above causes, other reasons for an iron deficit include:

  • Dietary ~ inadequate, vegetarian, vegan diets
  • Malabsorption syndromes ~ celiac disease Crohn’s disease, H/O gastric bypass or intestinal surgery
  • Antacid medications that interfere with iron absorption
  • Periods of life that require high iron demands~ infancy, adolescence, pregnancy and lactation
  • Patients with renal failure

(Braun, C.A., and Anderson, C.M., 2017)

 

Clinical manifestations range from fatigue and weakness to reduced cognitive performance. — Symptoms of iron-deficiency anemia include shortness of breath, fatigue, weakness, headaches, difficulty concentrating, brittle nails, pale skin, light headedness, sore tongue, and pica (NIH, 2018). However, because iron-deficiency anemia often develops slowly patients may be asymptomatic. In older adults diagnosed with anemia there is an increased susceptibility to falls and depression (Fairweather-Tait, et.al, 2014).

Statistics show that anemic adults have increased hospitalizations and mortality rates. Furthermore, there is a 17% incidence of Anemia in adults with Congestive Heart Failure with worse functioning capacity and survival rates (Le, 2016) Such evidences strengthen the fact that this is a critical health issue among the adults and elderly.

As per study from the National Health and Nutrition Examination Surveys (NHANES) from 2003 to 2012 data showed that anemia increased bimodally with peaks in age group of 40-49 and 80- 85 years of age. This is compounded by race at 35.6% or 6.4 more than the average for Black women aged 80-85 years of age. Overall, the study revealed a prevalence of moderate to severe anemia at 1-1.9% based on the World Health Organization (WHO) definition which was doubled from 2003-2004 to 2011-2012.These results indeed, required urgent public health interventions since the reduced oxygen capacity of the red blood cell’s hemoglobin has serious health implications that affect the morbidity and mortality of the health consumers (Le, 2016).

 

Assessment and Diagnosis are critical in the treatment regimen of iron deficiency anemia. The most common and cost-effective diagnostic tool for Anemia is Complete Blood Count (CBC) Peripheral blood smear in iron deficiency anemia exhibits Red Blood Cells which are irregular or cigar-shaped, microcytic(small), and hypochromic (pale). Other tests for patients with potential iron deficiency anemia include serum ferritin, iron level, and/or transferrin (Cadet, 2018).

In order to achieve an accurate diagnosis, one needs to obtain a precise medical history from the patient, a thorough physical exam, and laboratory tests. The World Health Organization defines anemia as a hemoglobin (Hbg.) of less than 13.0 g/dl in men, less than 12.0 g/dl. in non-pregnant women, and less than 11.0 g/dl in pregnant women. One must also take into consideration the wide variances in Hbg. levels across age and race. Additionally, people who use tobacco or who reside at altitude will have a higher Hbg. (Jiminez, K., et al, 2015).

Once the diagnosis of anemia is confirmed, one must search for the source or underlying condition that has caused the low blood counts. In reviewing the patient’s history and physical exam findings, the health care provider may require additional tests.  These may include:

  • Gynecological evaluation ~ for women with heavy menstrual bleeding
  • Gastroenterology consult ~ for abnormalities of the GI tract
  • Testing for underlying genetic diseases ~ Thalassemia, SCD.
  • Testing for autoimmune diseases, renal failure, inflammatory conditions

(American Society of Hematology, 2018).

 

Treatment and Management:

Treatment is two-fold.  First, one must treat the cause!

Second it is necessary to treat the iron deficiency. This treatment is guided by the degree of deficit and the urgency of replacement.

If dietary intake is the issue ~ diet change to include iron-rich foods is necessary. Meat, poultry, fish, dark green leafy vegetables, legumes and iron-rich pastas and grains (Jiminez., K. et al, 2015).

Pharmacologic management include oral iron supplement as the first line of treatment due to safety and low cost. However, this regimen possesses a low absorption of iron, and high incidence of gastrointestinal side effects hence, parenteral iron treatment like Ferric Carboxymaltose (FCM) and Iron Sucrose (IS) was introduced in clinical practice to overcome limitations and disadvantages related to oral iron. IV iron is more effective, better tolerated, and improves the quality of life of iron deficiency anemia patients compared with oral iron supplements. In a study conducted by Keklik et al (2017) FCM appears to provide a better and more rapid correction of serum ferritin levels in patients with iron deficiency anemia than IS. Evidence based studies are promising for those suffering iron deficiency anemia.

Anemia is now recognized as a risk factor for a number of adverse outcomes in the elderly, including hospitalization, morbidity, and mortality (Goodnaugh & Schrier, 2014).  Underlying etiology for the anemia such as chronic disease, iron deficiency, or myelodysplastic syndrome. Proper management of iron deficiency anemia help improve quality of life, alleviate the symptoms, and reduce the need for blood transfusions (Cadet, 2018).

 

REFERENCES:

 

American Society of Hematology, Iron-Deficiency Anemia. 2018.

Alaliwi, H. A., Abukashba, G. A., Alhussain, H. M., Alhasnani, M. H., Alzahrani, S. H., Alharthi, W. S., & … Alshuwaier, R. A. (2018). Nutritional Anemia Types and Management. Egyptian Journal Of Hospital Medicine70(6), 906-911.

Braun,C.,A.,&Anderson C.,M.(2017) Applied Pathophysiology : a Conceptual Approach      to the Mechanisms of Disease.(3rd Edition) Baltimore: Wolters Kluwer.

Cadet, M. J. (2018). Iron Deficiency Anemia: A Clinical Case Study. MEDSURG Nursing27(2), 108-120

Eckman, M., & Share, D. (2013). Pathophysiology Made Incredibly Easy!. Philadelphia: LWW.

Goodnough, L. T., & Schrier, S. L. (2014). Evaluation and management of anemia in the elderly. American Journal of Hematology89(1), 88–96.

Jiminea, K., Kulnigg-Dabsch, S., Gasche, C., Management of Iron Deficiency Anemia. Gastroenterology & Hepatology. 2015; 11(4): 241-247.

Keklik, M., Kalan, U., Korkmaz, S., Akyol, G., Aygün, B., & Keklik, E. (2017). Evaluation of Iron Sucrose and Ferric Carboxymaltose Therapies in Patients with Iron Deficiency Anemia. Erciyes Medical Journal / Erciyes Tip Dergisi, 39(2), 59-62. doi:10.5152/etd.2017.16102

Le, C. H. (2016). The Prevalence of Anemia and Moderate-Severe Anemia in the US Population (NHANES 2003-2012). Plos One, 11(11), e0166635. doi:10.1371/journal.pone.0166635

National Heart, Lung, and Blood Institute, NIH, Iron-Deficiency Anemia. 2014.

National Institutes of Health (NIH). (2018, July 09). Iron deficiency anemia: MedlinePlus Medical Encyclopedia. Retrieved from https://medlineplus.gov/ency/article/000584.htm

O’Neil, J. (2017). Diagnosing and Classifying Anemia in Adult Primary Care. Clinician Reviews, 27(8), 28-35.

Qamar, K., Saboor, M., Qudsia, F., Khosa, S. M., Moinuddin, & Usman, M. (2015). Malabsorption of iron as a cause of iron deficiency anemia in postmenopausal women. Pakistan Journal of Medical Sciences31(2), 304–308.

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