Editing Anemia (section)

====Microcytic====
{{main|Microcytic anemia}}
Microcytic anemia is primarily a result of hemoglobin synthesis failure/insufficiency, which could be caused by several etiologies:
{{columns-list|
* [[Heme]] synthesis defect
** [[Iron-deficiency anemia]] (microcytosis is not always present)
** [[Anemia of chronic disease]] (more commonly presenting as normocytic anemia)
* [[Globin]] synthesis defect
** Alpha-, and beta-[[thalassemia]]
** HbE syndrome
** HbC syndrome
** Various other unstable hemoglobin diseases
* [[Sideroblastic]] defect
** Hereditary sideroblastic anemia
** Acquired sideroblastic anemia, including [[lead poisoning|lead toxicity]]<ref>{{cite book |doi=10.1515/9783110434330-016 |chapter=Toxicology of Lead and Its Damage to Mammalian Organs |title=Lead – Its Effects on Environment and Health |date=2017 |series=Metal Ions in Life Sciences |volume=17 |pages=501–534 |pmid=28731309 |isbn=978-3-11-043433-0 | vauthors = Caito S, Lopes AC, Paoliello MM, Aschner M }}</ref>
** Reversible sideroblastic anemia
}}
Iron-deficiency anemia is the most common type of anemia overall and it has many causes. RBCs often appear hypochromic (paler than usual) and microcytic (smaller than usual) when viewed with a microscope.
* Iron-deficiency anemia is due to insufficient dietary intake or absorption of [[iron]] to meet the body's needs. Infants, toddlers, and pregnant women have higher than average needs. Increased iron intake is also needed to offset blood losses due to digestive tract issues, frequent blood donations, or [[Menorrhagia|heavy menstrual periods]].<ref name=irond>[https://www.cdc.gov/nccdphp/dnpa/nutrition/nutrition_for_everyone/iron_deficiency/index.htm Recommendations to Prevent and Control Iron Deficiency in the United States] {{webarchive|url=https://web.archive.org/web/20070420203221/http://www.cdc.gov/nccdphp/dnpa/nutrition/nutrition_for_everyone/iron_deficiency/index.htm |date=2007-04-20 }} MMWR 1998;47 (No. RR-3) p. 5</ref> Iron is an essential part of hemoglobin, and low iron levels result in decreased incorporation of hemoglobin into red blood cells. In the United States, 12% of all women of childbearing age have iron deficiency, compared with only 2% of adult men. The incidence is as high as 20% among African American and Mexican American women.<ref>{{cite journal|title=Iron Deficiency – United States, 1999–2000|journal=MMWR|date=October 11, 2002|volume=51|issue=40|pages=897–899|pmid=12418542|url=https://www.cdc.gov/mmwr/preview/mmwrhtml/mm5140a1.htm|access-date=21 April 2012|url-status = live|archive-url=https://web.archive.org/web/20120505040540/http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5140a1.htm|archive-date=5 May 2012|author1=Centers for Disease Control Prevention (CDC)}}</ref> In India it is even more than 50%.<ref>{{cite web |title=Global Iron-Deficiency Anemia Therapy Market – Industry Trends and Forecast to 2027 – |url=https://www.databridgemarketresearch.com/reports/global-iron-deficiency-anemia-therapy-market |access-date=2023-08-02 |website=Data Bridge Market Research}}</ref> Studies have linked iron deficiency without anemia to poor school performance and lower [[IQ]] in teenage girls, although this may be due to socioeconomic factors.<ref name=halterman1>{{cite journal | vauthors = Halterman JS, Kaczorowski JM, Aligne CA, Auinger P, Szilagyi PG | s2cid = 33404386 | title = Iron deficiency and cognitive achievement among school-aged children and adolescents in the United States | journal = Pediatrics | volume = 107 | issue = 6 | pages = 1381–1386 | date = June 2001 | pmid = 11389261 | doi = 10.1542/peds.107.6.1381 }}</ref><ref name=mcgregor1>{{cite journal | vauthors = Grantham-McGregor S, Ani C | title = A review of studies on the effect of iron deficiency on cognitive development in children | journal = The Journal of Nutrition | volume = 131 | issue = 2S–2 | pages = 649S–666S; discussion 666S–668S | date = February 2001 | pmid = 11160596 | doi = 10.1093/jn/131.2.649S | doi-access = free }}</ref> Iron deficiency is the most prevalent deficiency state on a worldwide basis. It is sometimes the cause of abnormal fissuring of the angular (corner) sections of the lips ([[angular stomatitis]]).
* In the United States, the most common cause of iron deficiency is bleeding or blood loss, usually from the [[gastrointestinal tract]]. [[Fecal occult blood|Fecal occult blood testing]], [[esophagogastroduodenoscopy|upper endoscopy]] and [[colonoscopy|lower endoscopy]] should be performed to identify bleeding lesions. In older men and women, the chances are higher that bleeding from the gastrointestinal tract could be due to [[Polyp (medicine)|colon polyp]]s or [[colorectal cancer]].
* Worldwide, the most common cause of iron-deficiency anemia is parasitic infestation ([[hookworm]]s, [[amebiasis]], [[schistosomiasis]] and [[Trichuris trichiura|whipworm]]s).<ref>{{cite web |url=https://www.who.int/nutrition/publications/en/ida_assessment_prevention_control.pdf |title=Iron Deficiency Anaemia: Assessment, Prevention, and Control: A guide for programme managers |access-date=2010-08-24 |url-status = dead|archive-url=https://web.archive.org/web/20110516122938/http://www.who.int/nutrition/publications/en/ida_assessment_prevention_control.pdf |archive-date=2011-05-16  }}</ref>
The [[Mentzer index]] (mean cell volume divided by the RBC count) predicts whether microcytic anemia may be due to iron deficiency or thalassemia, although it requires confirmation.<ref>{{cite journal | vauthors = Mentzer WC | title = Differentiation of iron deficiency from thalassaemia trait | journal = Lancet | volume = 1 | issue = 7808 | pages = 882 | date = April 1973 | pmid = 4123424 | doi = 10.1016/s0140-6736(73)91446-3 }}</ref>{{citation needed|date=August 2013}}