Читать книгу Pathy's Principles and Practice of Geriatric Medicine - Группа авторов - Страница 356

Weight loss and resulting adverse outcomes in older adults may be due to cachexia, malnutrition, the physiological anorexia of ageing, or some combination of these factors. Although there is often considerable overlap between them, cachexia and malnutrition are not the same. Whereas all cachectic patients are malnourished, not all malnourished patients are cachectic. Cachexia is a complex metabolic syndrome associated with underlying illness and characterized by loss of muscle with or without loss of fat mass. The prominent clinical feature of cachexia in adults is weight loss, but inflammation is a key component. Anorexia, insulin resistance, and increased muscle protein breakdown are also frequently associated with cachexia. Cachexia is distinct from starvation, age‐related loss of muscle mass, primary depression, malabsorption, and hyperthyroidism. Inflammation plays a major role in the pathogenesis of cachexia, with an absolute or relative increase in levels of inflammatory cytokines such as tumour necrosis factor alpha (TNF‐α), interleukin‐1, and interleukin‐6. Conditions that often afflict older people and that are frequently associated with cachexia include cancer, cardiac failure, chronic obstructive pulmonary disease and chronic renal failure. The European Society for Clinical Nutrition and Metabolism sub‐classified cachexia based on severity into cachexia and pre‐cachexia, the latter being present when there is (i) an underlying chronic disease, (ii) a systemic inflammatory response, (iii) anorexia, and (iv) unintentional weight loss over the previous six months of less than 5% of usual body weight.^21,22