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Chapter 072. Malnutrition and Nutritional Assessment (Part 3)

Physiologic Characteristics of Hypometabolic and Hypermetabolic States The metabolic characteristics and nutritional needs of hypermetabolic patients who are stressed from injury, infection, or chronic inflammatory illness differ from those of hypometabolic patients who are unstressed but chronically starved. In both cases, nutritional support is important, but misjudgments in selecting the appropriate approach may have disastrous consequences. The hypometabolic patient is typified by the relatively unstressed but mildly catabolic and chronically starved individual who, with time, will develop marasmus. The hypermetabolic patient stressed from injury or infection is catabolic (experiencing rapid breakdown of body mass) and is at high risk for developing. | Chapter 072. Malnutrition and Nutritional Assessment Part 3 Physiologic Characteristics of Hypometabolic and Hypermetabolic States The metabolic characteristics and nutritional needs of hypermetabolic patients who are stressed from injury infection or chronic inflammatory illness differ from those of hypometabolic patients who are unstressed but chronically starved. In both cases nutritional support is important but misjudgments in selecting the appropriate approach may have disastrous consequences. The hypometabolic patient is typified by the relatively unstressed but mildly catabolic and chronically starved individual who with time will develop marasmus. The hypermetabolic patient stressed from injury or infection is catabolic experiencing rapid breakdown of body mass and is at high risk for developing kwashiorkor if nutritional needs are not met and or the illness does not resolve quickly. As summarized in Table 72-2 the two states are distinguished by differing perturbations of metabolic rate rates of protein breakdown proteolysis and rates of gluconeogenesis. These differences are mediated by proinflammatory cytokines and counterregulatory hormones tumor necrosis factor interleukins 1 and 6 C-reactive protein catecholamines epinephrine and norepinephrine glucagon and cortisol that are relatively reduced in hypometabolic patients and increased in hypermetabolic patients. Although insulin levels are also elevated in stressed patients insulin resistance in the target tissues prevents insulin-mediated anabolic actions. Table 72-2 Physiologic Characteristics of Hypometabolic and Hypermetabolic States Physiologic Characteristics Hypometabolic Nonstressed Patient Cachectic Marasmic Hypermetabolic Stressed Patient Kwashiorkor Risk Cytokines Physiologic Characteristics Hypometabolic Nonstressed Patient Cachectic Marasmic Hypermetabolic Stressed Patient Kwashiorkor Risk catecholamines glucagon cortisol insulin Metabolic rate O2 consumption Proteolysis gluconeogenesis .