Clinical Comment

This disease is one of several myopathies caused by defects in the 

This chapter reviews the epidemiological burden of CRF and highlights several issues  

The sources of data on the prevalence of CRF are mostly indirect and not universally available in all countries and regions. Thus, an exact picture of CRF as a global issue remains largely incomplete, both in terms of geographical distribution and the global dimension. Multinational surveys, such as the Eurovent study, can provide insights into the use of HMV. 

The most important cause of CRF requiring LTMV at home are neuromuscular and skeletal conditions. 

The management of CRF varies regionally, nationally, and in different health care systems. These factors directly affect the epidemiology of CRF. The clinical and economic impact of different approaches to HMV is largely unknown. 

The networks for collection of uniform data are likely to be informative. Such systems will better characterize patients, by including information on criteria for diagnosis, smoking habits, comorbidities, and socioeconomic conditions. 

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Substance Mechanism Half-life Time to steady-state Clinical comments... 

Lotta Topaigne suffered enormously painful gout attacks affecting her great toe (see Clinical Comments, Chapters). The extreme pain was caused by the release of a leukotriene that stimulated pain receptors. The precipitated urate crystals in her big toe stimulated recruited inflammatory cells to release the leukotriene. 

Aspirin, by covalently acetylating the active site of cyclooxygenase, blocks the production of TXAj from its major precursor, arachidonic acid. By causing this mild hemostatic defect, low-dose aspirin has been shown to be effective in prevention of acute myocardial infarction (see Clinical Comments). For Ivan Applebod (who has symptoms of coronary heart disease), aspirin is used to prevent a first heart attack (primary prevention). For Ann Jeina and Cora Nari (who already have had heart attacks), aspirin is used to prevent a second heart attack (secondary prevention). 

Hartnup disease Is another genetically determined and relatively rare autosomal recessive disorder. It is caused by a defect in the transport of neutral amino acids across both intestinal and renal epithelial cells. The signs and symptoms are, in part, caused by a deficiency of essential amino acids (see Clinical Comments). Cystinuria and Hartnup disease involve defects in two different transport proteins. In each case, the defect is present both in intestinal cells, causing malabsorption of the amino acids from the digestive products in the intestinal lumen and in kidney tubular cells, causing a decreased resorption of these amino acids from the glomerular filtrate. 

Jean Ann Tonich s megaloblastic anemia was treated, in part, with folate supplements (see Clinical Comments). Within 48 hours of the initiation of folate therapy, megaloblastic or "ineffective" erythropoiesis usually subsides, and effective erythropoiesis begins. 

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