Anemias definition

Several reports identified nonlethal effects in humans acutely exposed to arsine. These reports, however, lacked definitive exposure data but verified hematologic disorders leading to renal failure as critical effects of arsine exposure. Bulmer et al. (1940) (as cited in Elkins 1959) reconstructed an exposure incident at a gold extraction facility and estimated that subchronic (up to 8 mon) exposure to 0.12 ppm arsine resulted in jaundice and anemia (see Section 2.2.1). The lack of definitive exposure data for humans necessitates the use of animal data for quantitative estimation of AEGL values. Derivation of AEGL-2 values based upon limited human data (Flury and Zernik 1931) was considered but rejected because the data were poorly documented and inconsistent with other data showing lethality at lower cumulative exposures. 

The fibroblasts do not convert cyanocobalamin or hydroxocobalamin to methylcobalamin or adenosyl-cobalamin, resulting in diminished activity of both N5-methyltetrahydrofolate homocysteine methyltransferase and methylmalonyl-CoA mutase. Supplementation with hydroxocobalamin rectifies the aberrant biochemistry. The precise nature of the underlying defect remains obscure. Diagnosis should be suspected in a child with homocystinuria, methylmalonic aciduria, megaloblastic anemia, hypomethioninemia and normal blood levels of folate and vitamin B12. A definitive diagnosis requires demonstration of these abnormalities in fibroblasts. Prenatal diagnosis is possible. 

Study of plasma catalase activity on an individual basis has been limited in scope. For 50 adults the range was found to be from 4.2 to 9.5 per ml. of plasma. 19 One of the normal individuals was studied for five days, and the following values were obtained 9.5, 8.5, 9.5, 7.0, 9.5. Further study is required before one could conclude definitely that there are significant inter-individual differences. The available evidence points in that direction. In various anemias the values may be 50 or more. In one "diagnostic problem case" the value was 42. It seems highly probable that "normal" differences have physiological significance. 

The diagnosis (definite or possible endocarditis) according to the 1992 Duke s criteria (see Mandell et al., 2000) is based on blood cultures and echocardiography, the patient s history and findings upon physical examination. This diagnosis should always be considered in patients presenting with fever of unknown origin, especially when they also have a heart murmur and/or normocytic, normochromic anemia. 

Azathioprine and mercaptopurine appear to be of definite benefit in maintaining renal allografts and may be of value in transplantation of other tissues. These antimetabolites have been used with some success in the management of acute glomerulonephritis and in the renal component of systemic lupus erythematosus. They have also proved useful in some cases of rheumatoid arthritis, Crohn s disease, and multiple sclerosis. The drugs have been of occasional use in prednisone-resistant antibody-mediated idiopathic thrombocytopenic purpura and autoimmune hemolytic anemias. 

The definition of risk is the probability times the consequences (Figure 20.1). So the probability of an immune response is not synonymous with its risk. A high risk can be associated with a relative high probability, but also with a low probability if the consequences are severe. For example, the probability of an immune response to epoetin is rather low, but one of the consequences, antibody-induced severe anemia, is severe [3], This makes the risk of immunogenicity of epoetins relatively high. 

Pedantry introduced the term hypogammaglobulinemia (although we are all quite happy to talk about anemia). Deficiency of IgG can be arbitrarily defined as severe when the serum level is less than 200 mg/100 ml 20% MNA, see Section 6.2 and Table 4), or moderate when from 200 to the —2 SD lower limit of normal for age, and in this review I use the terms severe AG and moderate AG to describe these. During the first 6 months of life, infants commonly show levels below 20% MNA, so that in this period 10% MNA (100 mg/100 ml) is better used as the arbitrary limit (Mil). Although these definitions are arbitrary they are useful in that it is known that within one year 70% of patients with severe AG will suffer severe infection (H19) and that without treatment 65% may die (MU). Moderate AG is complicated within a year by severe infection 40% (H19), but as this is so common (H25, MU) my present policy is chiefly to observe such patients some will earn their y-globulin treatment, others can manage with supportive measures such as early treatment of any infection. 

This chapter will provide an overview of anemia. This first section will present definitions and classification systems. A review of basic aspects of erythropoiesis, followed by laboratory evaluation of the anemia patient will then be discussed. The general similarities in the clinical presentation of the anemic patient will be presented in the text. 

Table 99-3 shows normal hematologic values. By definition, anemia is present in males if the Hct is less than 41% or the Hgb is less than 13 g/dL, while females have a Hct less than 36% or a Hgb less than 12 g/dL. 

A ferric - D-fructose complex of definite composition but unknown structure has been described it is soluble in water and may be suitable for the treatment of anemia. 

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