underlying mechanism is an autoimmune gastritis that results in achlorhydria

Underlying mechanism is an autoimmune gastritis that

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underlying mechanism is an autoimmune gastritis that results in achlorhydria and the absence of intrinsic factor. Helicobacter pylori may be an initiating factor for the gastritis but usually cannot be detected when PA develops. The incidence of PA peaks at age 60; the condition has a female :male incidence of 1.6 : 1.0 and is more common in those with early greying, blue eyes and blood group A, and in those with a family history of the disease or of diseases that may be associated with it – for example, vitiligo (Figure 2.1), myxoedema, Hashimoto’s disease, Addison’s disease of the adrenal gland and hypoparathyroidism. Other causes of severe B12 deficiency are infrequent in Britain. B12 is only present in foods of animal origin, such as meat, fish, eggs, cheese and other dairy products. It is absent from fruit, vegetables and nuts. Veganism is an unusual cause of severe deficiency, as most vegetarians and vegans include some B12 in their diet. Moreover, unlike in PA, the enterohepatic circulation for B12 is intact in vegans, so B12 in bile is reabsorbed and stores are conserved. Gastric resection and intestinal causes of malabsorption of B12 are less common causes of the deficiency than PA is in the UK. Macrocytic Anaemias Victor Hoffbrand University College London, London, UK OVERVIEW • Macrocytic red cells (mean cell volume >95 fL) may be associated with a megaloblastic or normoblastic bone marrow. • Deficiencies of either vitamin B12 or folate lead to defective DNA synthesis, megaloblastic
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  • Spring '18
  • Mr. kanor
  • vitamin B12 deficiency, Vitamin B12, Pernicious anemia, Deficiency of vitamin B12

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