Acquired Iron Deficiency

Iron-deficiency anaemia results from a discrepancy between iron availability and the amount required for production of red blood cells. The causes of acquired iron deficiency in so-called underdeveloped and developed countries must be differentiated. In underdeveloped countries, the main causes of iron deficiency are (a) the poor availability of iron in the diet due to low haem and high fibre and phytate content (D Souza et ah, 1987), and (b) chronic blood loss due to hookworm, schistosomiasis and malaria (Stoltzfus et ah, 1997 Olsen et ah, 1998 Dreyfuss et ah, 2000). Inflammation and vitamin A deficiency often interfere with the above causes of iron deficiency, causing a mixed type of anaemia. In underdeveloped countries diet improvement, iron fortification of natural foods and eradication of parasites will have a much higher impact than will refinement of diagnostic procedures and therapy of iron-deficiency anaemia. 

Transferrin is essential for movement of iron and without it, as in genetic absence of transferrin, iron overload occurs in tissues. This hereditary atransferrinemia is coupled with iron-deficiency anemia. The iron overload in hereditary or acquired hemochromatosis results in fully saturated transferrin and is treated by phlebotomy (10). 

Since there is no true excretion of iron from the body, iron-deficiency anemia occurs mostly because of inadequate absorption of iron or excess blood loss. Inadequate absorption may occur in patients who have congenital or acquired intestinal diseases, such as inflammatory bowel disease, celiac disease, or bowel resection. Achlorhydria and diets poor in iron also may contribute to poor absorption of iron. In contrast, iron deficiency also may occur in patients who exhibit a higher rate of iron loss from the body. This is manifested in... 

A system of internal iron exchange exists which is dominated by the iron required for hemoglobin synthesis. For formation of red blood cells, iron stores ean furnish It)—U> ingAl of iron, as compared to 1-1 mg from dietary sources Only ca 10 wl r+ of ingested iron actually is absorbed. Transferrin is essential for movement of iron and without it. as in genetic absence of transferrin, iron overload occurs in tissues. This hereditary. iiransferrinemui is coupled with iron-deficiency anemia. The iron overload in hereditary or acquired hemochromatosis results in fully saturated transferrin and is treated by phlebotomy. 

The relative amount of p chain variants (and of Hb-Aa) is markedly decreased in individuals who also have a megoloblastic anemia or an iron deficiency anemia (H8, L15). Acquired conditions apparently will influence the activity of specific genomes. 

A 46-year-old woman is prescribed doxycycline for a diagnosis of community-acquired pneumonia. Her PMH is significant for iron-deficiency anemia, peptic ulcer disease, HTN, a recent DVT, and headaches. Her current medications include ferrous sulfate, ibuprofen, enalapril, acetaminophen, famotidine, and warfarin. Which of her following medications is most likely to result in decreased levels of doxycycline ... 

Secondary hemochromatosis is the consequence of the uicreased administration and absorption of iron. The administration of iron includes that given with the transfusions that are required in certain anemic patients and the ill-advised and unfortunate administration of iron to anemic patients who are not actually iron deficient. The most common causes of secondary hemochromatosis are thalassemia major and acquired myelodysplastic states, but there are many other circumstances in which secondary iron overload occurs, including pyruvate kinase deficiency and congenital dyserythropoietic anemias. 

At normal levels of iron intake, absorption requires uptake from the intestinal lumen by the mucosa and transfer from the mucosa to the portal blood. Both events are inversely affected by the state of body iron stores. In iron deficiency states, nonferrous metals such as cobalt and manganese, which have an ionic radius similar to that of iron and form octahedral complexes with six-coordinate covalent bonds, also are absorbed at an increased rate. Oral administration of a large dose of iron reduces (or temporarily inhibits) the absorption of a second dose of iron by the absorptive enterocytes even in the presence of systemic iron deficiency. The mechanism of mucosal block, which resists acquiring additional iron by the en-teroeytes with high amounts of intracellular iron, is not yet understood. It probably involves set points established in the enterocytes for iron recently consumed in the diet (dietary regulator). 

Iron deficiency is a serious nutritional disorder in many crops on neutral and alkaline aerobic soils because of the low availability of iron. However, some gramineous plants such as barley and wheat have developed a specific strategy to acquire sparingly soluble iron in soil they produce MAs which, as already mentioned, are involved in the iron acquisition process as phytosiderophores. The process of iron acquisition by plants has been divided into four steps, namely Fe-deficiency-induced biosynthesis of MAs inside the roots, secretion of MAs to the rhizosphere, solubilization of sparingly soluble inorganic Fe(III) in soils by chelation with MAs, and specific uptake of MA-Fe(III) complexes by the roots [32],... 

Parkinson s disease 253-4, 298 pathophysiology of iron in humans 228 absorption disorders 211-20 acquired and genetic disorders 207 deficiency... 

Until 1950, 13 mineral elements were classified as essential these comprised the major elements (calcium, phosphorus, potassium, sodium, chlorine, sulphur, magnesium) and the micro or trace elements (iron, iodine, copper, manganese, zinc and cobalt). By 1970, molybdenum, selenium, chromium and fluorine had been added to the list subsequently, arsenic, boron, lead, lithium, nickel, silicon, tin, vanadium, rubidium and aluminium have also been included, the list varying slightly according to the different authorities. Plant and animal tissues contain a further 30 mineral elements, in small quantities, for which no essential function has been found. They may be acquired from the environment, but it has been suggested that as many as 40 or more elements may have metabolic roles in mammalian tissues. Fortunately, many of these trace elements, especially those of more recent discovery, are required in such minute quantities, or are so widely distributed in foods for animals, that deficiencies are likely to be extremely rare under normal practical conditions. 

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