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ANEMIA
Definition of Anemia:-
The Definition of anemia has attracted considerable interest recently because of epidemiologic studies that suggest that anemia may be associated with poorer outcomes in a variety of disorders. In many studies the definition of anemia used is that suggested by a WHO expert committee nearly 40 years ago.^1 Bearing the imprimatur of the WHO apparently carries much weight, although, as we shall point out, the numbers so casually presented in that document were based on very few data using methods that were inadequate. A reproduction of the entire section dealing with the establishment of this standard is shown in Figure 1. Cook et al 2 (p3362) recently lamented “the near universal acceptance of the WHO criteria of anemia.” As we will show, the acceptance of these standards is, indeed, to be decried. Table 1 summarizes the “lower limit of normal” offered by the WHO committee and various other sources.
Figure 1. A reproduction of the page of the WHO report that has been used as a standard for anemia in epidemiologic studies. The casual treatment of the lower level of normal, given in whole numbers without decimal points in this 40- page document dealing with nutritional ...
Table 1. Lower limits of normal of hemoglobin concentration of the blood of adult men and women as assessed by various sources
The differences in the stated lower limits of normal may seem small, but in their application they are far from trivial. For example, assuming a Gaussian distribution of the data one may calculate that if the 142-g/L(14.2-g/dL) cutoff proposed by Jandl^3 is correct, a man with a 130-g/L(13-g/dL)
hemoglobin concentration, therefore passing the WHO standard for anemia, would be in the lowest 0.01% of the distribution of hemoglobin values. Conversely, if the WHO standards were correct, the cutoff value given by Jandl 3 would
result in adjudging 22% of all healthy men to be anemic.
How is one, then, to find a hemoglobin concentration above which 95% or 97.5% of the normal subjects are included? In the past, a part of the problem has been the availability of large databases that are sufficiently well documented to allow exclusion of individuals who are not “normal.” The systematic exclusion of such population members is important in dealing with an abnormality that is as common as is anemia, particularly in women. Fortunately, at least 2 such databases now exist. One is the NHANES-III (the third US National Health and Nutrition Examination Survey) database, the other the Scripps-Kaiser database that we collected in the San Diego area between 1998 and 2002. 10,11^ The ethnic origin of
the individuals designated as white in these 2 databases is probably very similar. White Americans are a genetic mixture
and also many of those with the anemia of chronic inflammation, in which the transferrin saturation is also usually low. We were also able to determine whether excessive alcohol intake, diabetes mellitus, renal failure, or inflammatory markers (C-reactive protein in NHANES, erythrocyte sedimentation rate in Scripps-Kaiser, elevated serum ferritin, or leukocytosis) affected the hemoglobin concentrations in these populations. None of these had an effect in the younger subjects, but in older subjects a serum creatinine of more than 106 μM (1.4 mg/dL) and elevated inflammatory markers (ESR > 30 in women and ESR > 20 in men or CRP > 1 mg/dL) were associated with significantly lower mean hemoglobin values.
Table 2. Mean hemoglobin (g/dL) by sex and age in white and black subjects
Older subjects with elevated creatinine and ESR or CRP were thus excluded from our calculations. Pregnant women were also excluded. Overall, the percentage of subjects excluded from the analysis ranged from 10% to 30%, except for black subjects in NHANES, in which the exclusion rate was approximately 50% for older men and 40% for women.
The mean and 1.65 standard deviation below the mean of the hemoglobin values of the white subjects are shown in Figure 2 ; this provides the hemoglobin concentration below which only 5% of normal subjects in the population will be found, given the Gaussian distribution of hemoglobin values. Table 3 presents the lower limit of normal for white and black men
and women. These data are presented to indicate the 2.5th and the 5th percentile as the actual percentile in the data set and as the predicted value based on the assumption that the hemoglobin values have a Gaussian distribution, as assumed in Figure 2. This assumption is clearly valid, as shown by the excellent correspondence between the predicted cutoff and the actual cutoff based on the number of cases found.
Figure 2. The mean and -1.65 standard deviations of the hemoglobin values of the white subjects in the Scripps-Kaiser and NHANES-III databases after applying the criteria described in the text. The bottom of the error bars represents the hemoglobin value below ...
Table 3. Lower limits of normal for hemoglobin concentration of the blood in g/dL of younger (age 20-59 for men; 20-49 for women) and older white and black adults
The results obtained from the 2 databases are in very good agreement, but there are some minor differences that reach statistical significance. In particular, the mean hemoglobin of older men is slightly higher in the Scripps-Kaiser data than in the NHANES data. The latter difference in Table 3 is clearly an artifact resulting from the consolidation of all subjects older than 60 years into one group. As shown in Table 2, there are a higher proportion of men older than 80 years in the
times,^15 the dilution of blood, sometimes obtained by finger puncture,^16 was carried out with pipettes that were often inaccurate. Cyanmethemoglobin standards were not widely available, and calibration required oxygenation of a blood sample to serve as a standard with measurement of the amount of oxygen released by acid in a van Slyke apparatus. Needless to say, this procedure was not always carried out, and, as a consequence, results were often unreliable. In view of these difficulties, perhaps we should marvel not only at the fact that the WHO standard is still used but also that it was not further from the mark.
What, then, are reasonable benchmarks for anemia for a clinician to use today, based on today's improved laboratory practice and the data that we have been able to marshal from the Scripps-Kaiser and the NHANES study? The suggested lower limits of normal are summarized in Table 4. Based mostly on the larger Scripps-Kaiser database, but confirmed by the NHANES data, it would seem that a hemoglobin concentration below 137 g/L (13.7 g/dL) in a white man aged between 20 and 60 years would have only an approximately 5% chance of being a normal value. For older men, this hemoglobin value would be 132 g/L (13.2 g/dL). The corresponding value for women of all ages would be 122 g/L (12.2 g/dL). As shown in Table 1 and in a number of previous studies,17,18^ the lower limit of normal of hemoglobin
concentrations of African Americans are appreciably lower. Although some of this difference is a result of the high frequency of α-thalassemia in this population, other, as-yet- unidentified genes are involved, and because the gene frequency for α-thalassemia is extraordinarily high in the black population, and the diagnosis is not readily made, we judge it best not to censor such cases in determining the normal range for the black population.
Table 4. Proposed lower limits of normal for hemoglobin concentration of the blood for white and black adults
References:-
- Blanc B, Finch CA, Hallberg L, et al. Nutritional anaemias.
Report of a WHO Scientific Group. WHO Tech Rep Ser.
1968;405: 1-40.
- Cook JD, Flowers CH, Skikne BS. The quantitative assessment of body iron. Blood. 2003;101: 3359-3364. [ PubMed]
- Jandl JH. Blood. Boston, MA: Little, Brown and Company;
- Beutler E, Lichtman MA, Coller BS, Kipps TJ, Seligsohn U. Williams Hematology. New York, NY: McGraw-Hill;
- Lee GR, Foerster J, Lukens J, Paraskevas F, Greer JP, Rodgers GM. Wintrobe's Clinical Hematology. Baltimore, MD: Williams and Wilkins; 1998.
- Rapaport SI. Introduction to Hematology. Philadelphia, PA: JB Lippincott Company; 1987.
Pre-incidence Anaemia:-
Pre-incidence anaemia is a relatively common finding, affecting a third of patients undergoing elective surgery. Traditionally associated with chronic disease, management
**2. Musallam KM, Tamim HM, Richards T, et al. Preoperative anaemia and postoperative outcomes in non- cardiac surgery: a retrospective cohort study. Lancet 2011; 378: 1396– 407.
- Ferraris VA, Davenport DL, Saha SP, Austin PC, Zwischenberger JB. Surgical outcomes and transfusion of minimal amounts of blood in the operating room. Archives of Surgery 2012; 147: 49–55.
- JPAC – Joint United Kingdom (UK) Blood Transfusion and Tissue Transplantation Services Professional Advisory Committee. Patient Blood Management, 2014. www.transfusionguidelines. org.uk/uk-transfusion- committees/national-blood-transfusioncommittee/patient- blood-manageme**
nt (accessed 13/08/2014).
Causes:-
Red blood cells contain hemoglobin — an iron-rich protein that gives blood its red color. Hemoglobin enables red blood cells to carry oxygen from your lungs to all parts of your body and to carry carbon
dioxide from other parts of the body to your lungs so that it can be exhaled.
Most blood cells, including red blood cells, are produced regularly in your bone marrow — a spongy material found within the cavities of many of your large bones. To produce hemoglobin and red blood cells, your body needs iron, vitamin B-12, folate and other nutrients from the foods you eat.
Causes of anemia
Different types of anemia and their causes include:
- Iron deficiency anemia. This is the most common type of anemia worldwide. Iron deficiency anemia is caused by a shortage of iron in your body. Your bone marrow needs iron to make hemoglobin. Without adequate iron, your body can't produce enough hemoglobin for red blood cells.
Without iron supplementation, this type of anemia occurs in many pregnant women. It is also caused by blood loss, such as from heavy menstrual bleeding, an ulcer, cancer and regular use of some over-the- counter pain relievers, especially aspirin.
- Vitamin deficiency anemia.:-
- In addition to iron, your body needs folate and vitamin B-12 to produce enough healthy red blood cells. A diet lacking in these and other key nutrients can cause decreased red blood cell production.
replace them. Certain blood diseases increase red blood cell destruction. You can inherit a hemolytic anemia, or you can develop it later in life.
References:-
- Recommendations to prevent and control iron deficiency in the United States. Centers for Disease Control and Prevention. MMWR Morb Mortal Wkly Rep 1998; 47(RR-3):1.
- (^) Auerbach M, Goodnough LT, Picard D, Maniatis A. The role of intravenous iron in anemia management and transfusion avoidance. Transfusion 2008; 48:988.
- Baker WF Jr. Iron deficiency in pregnancy, obstetrics, and gynecology. Hematol Oncol Clin North Am 2000; 14:1061.
Anemia Signs and Symptoms :-
People who are anemic most often experience fatigue. While it’s normal to feel tired after a long day at work or a heavy exercise session, when you're anemic, you feel weary after shorter and shorter periods of exertion as your body's cells become starved for oxygen.
As anemia worsens, your body can experience visible physical changes — your skin could become pale, your nails brittle and cuts may take longer to stop bleeding.
Other symptoms associated with anemia include:
- Shortness of breath
- Irritability
- Weakness
- Dizziness
- Cold hands and feet
- Racing or irregular heartbeat
- Inability to concentrate or think clearly
- Chest pain
- Sexual dysfunction
These symptoms are likely to be very light at first, especially if you have mild or moderate anemia. Our bodies are very adaptable, and will try to compensate for the loss of oxygen in the blood. As anemia advances, your body will be
- Jump up^ Tayles, N (Sep 1996). "Anemia, genetic diseases, and malaria in prehistoric mainland Southeast Asia". American Journal of Physical Anthropology. 101 (1): 11–27. doi : 10.1002/ (SICI)1096-8644(199609)101:1<11::AID- AJPA2>3.0.CO;2-G. PMID 8876811
Diagnosis:-
To diagnose anemia, your doctor may ask you about your medical and family history, perform a physical exam, and run the following tests:
- Complete blood count (CBC). :-
- (^) A CBC is used to count the number of blood cells in a sample of your blood. For anemia your doctor will be interested in the levels of the red blood cells
contained in the blood (hematocrit) and the hemoglobin in your blood.
Normal adult hematocrit values vary from one medical practice to another but are generally between 40 and 52 percent for men and 35 and 47 percent for women. Normal adult hemoglobin values are generally 14 to 18 grams per deciliter for men and 12 to 16 grams per deciliter for women.
- A test to determine the size and shape of your
red blood cells. :-
- Some of your red blood cells may also be examined for unusual size, shape and color.
Additional diagnostic tests:-
If you receive a diagnosis of anemia, your doctor may order additional tests to determine the underlying cause. For example, iron deficiency anemia can result from chronic bleeding of ulcers, benign polyps in the colon, colon cancer, tumors or kidney problems.
Occasionally, it may be necessary to study a sample of your bone marrow to diagnose anemia.
References:- Maakaron, Joseph (30 September 2016). "Anemia: Practice Essentials, Pathophysiology, Etiology"
. Emedicine. Archived from the original on 14 October 2016_. Retrieved 30 October 2016_.
poor performance of the immune system and this together has a negative impact on social and economic development. 2 Mild to moderate anemia is one of the
factors for women who are at risk of dying from one of the five major causes of maternal mortality, namely. haemorrhage, eclampsia, abortion, obstructed labor and sepsis. 3 Iron deficiency is mainly prevalent in pre school
children, school children, adolescent females and pregnant women. What should be the strategies to prevent these groups from the consequences of iron deficiency? Enrichment and fortification of food, dietary modification, and iron supplementation are the well- established modalities for the prevention of iron deficiency. Fortification of infant formulas and consumption of fortified and iron rich products by lactating women and young infants have dramatically reduced the prevalence in the developed countries but the overall picture is dismal because of poverty, illiteracy and poor health care system. 4 Another emerging field is
the hiomanipulation of micronutrients by genetically deleting iron absorption inhibitors e.g. removal of phytic acid from maize and beans and thereby increasing the bioavailahility of micronutrient. 4
Iron supplementation is one of the most effective way to prevent and treat iron deficiency however, there are controversies regarding frequency of administration of oral iron and the dosage formulation. 5 Daily oral iron supplements are effective at reducing the prevalence of anemia but at the cost of variable gastrointestinal side effects leading to poor compliance. An alternate approach to daily versus weekly iron supplementation has been suggested based on the mucosal block in rats. It has been noted that iron absorption is reduced in rats in the days immediately after the initial administration of
iron and this introduced the mucosal block theory. however, the studies in humans have clearly revealed that there is no such mucosal block during iron supplementation that is responsible for a reduction in iron absorption in rats. One of the main indications for iron supplementation is pregnancy and with weekly administration the total iron deficit in the body will be substantial and can seriously harm both mother and fetus. 6
As far as the dose is concerned, a daily dose of 60 mg of ferrous iron throughout the second half of the pregnancy should be sufficient to prevent iron deficiency. A dose of 120mg daily will be required for non pregnant iron deficient females or in females who were unable to start supplementation therapy in second trimester. 7 Adolescent females is another group which should be targeted because adolescent pregnancies are not uncommon in our country and the objective should he the preparation of potential mother’s nutritional status in anticipation of pregnancy that will reduce the likelihood of complications and would increase the overall survival of mothers and infants. 2 The third group that should he targeted is preschool and school children. Recently. Human Nutrition Unit of the All india Institute of Medical Sciences published the recommendations on strategies for prevention and control of iron deficiency anemia amongst children below the age of three years. Issues like the age group for iron supplementation, type of iron compounds, dosage, daily versus weekly administration and duration of iron supplementation have been (liScuSsed. The recommendations for children of group of upto three years include the use of Ferrous sulphate 20mg once daily in the form of drops that should be administered for
