Muscle mass malnutrition

The protein anabolic compounds are most commonly used to stimulate appetite and muscle mass in persons with advanced malignancy or other conditions characterized by advanced malnutrition. These compounds are also often abused by athletes who are trying to build muscle mass. Athletes often take multiple compounds at the same time (stacking) or sequentially to try to maximize their anabolic effects. This type of use is not based on scientific data but rather on hyperbole often spread by individuals with no medical or scientific background. Athletes who use these compounds in this way are unaware of the potential adverse effects or do not care. 

While low serum cholesterol levels have been observed in malnourished patients, largely as a result of decreased synthesis of lipoproteins in the liver, hypocholesterolemia occurs later in the course of malnutrition and is therefore not useful as a screening test. PEM usually results in low serum urea nitrogen (BUN), urinary urea, and total nitrogen. Estimation of 24-h urine creatinine excretion is also a valuable biochemical index of muscle mass (when there is no impairment in renal function). The urinary CHI is correlated to lean body mass and anthropometric measurements. In edematous patients, for whom the extracellular fluids contribute to body weight and spuriously high body mass index values, the decreased CHI values are especially useful in diagnosing malnutrition. 

Body mass index (weight in kg divided by the height squared in metres) is a reasonable indicator of nutritional state, except when the patient is oedematous. Arm circumference is an indicator of skeletal muscle mass, while skin fold thickness is proportional to body fat levels. In addition, general physical examination may reveal signs of malnutrition in the skin, nails, hair, teeth and mucous membranes. 

Creatinine is a product of the degradation of creatine and creatine phosphate, which are present mainly in muscle and in food. Plasma creatinine is dependent on muscle mass and can be lowered in severe myopathy. Although plasma levels are less affected by diet compared to urea, malnutrition may lower plasma creatinine (Evans 1987 Braun, Lefebvre, and Watson 2003). Plasma creatinine is normally filtered from the plasma, and it is reabsorbed and secreted by the proximal tubules to a minor extent, although secretion is higher in rodents compared to humans. Elevated plasma creatinine is a reliable indicator of impaired glomerular filtration or alterations in renal blood flow, but severe tubular dysfunction can also increase plasma creatinine. 

Mid-Arm Anthropometry. The arm muscle circumference (AMC), also called the mid upper arm muscle circumference (MUAMC), reflects both caloric adequacy and muscle mass and can serve as a general index of marasmic-type malnutrition. The arm circumference is measured at the midpoint of the left upper arm by a fiberglass flexible-type tape. The arm muscle circumference can be calculated from a formula that subtracts a factor related to the skinfold thickness (SFT) from the arm circumference ... 

The liver synthesizes a number of serum proteins and releases them into the blood. These proteins decrease in the blood during protein malnutrition. Two of these serum proteins, albumin and transferrin (an iron-binding transport protein), are often measured to assess the state of protein malnutrition. Serum albumin is the traditional standard of protein malnutrition. Neither measurement is specific for protein malnutrition. Serum albumin and transferrin levels decrease with hepatic disease, certain renal diseases, surgery, and a number of other conditions, in addition to protein malnutrition. Serum transferrin levels also decrease in iron deficiency. Percy Veere s values were below the normal range for both of these proteins, indicating that his muscle mass is unable to supply sufficient amino acids to sustain both synthesis of serum proteins by the liver and gluconeogenesis. 

Malnutrition is highly prevalent among patients requiring PMV (37) and LTMV (70) and is assoeiated with poor prognosis (71). Malnutrition decreases muscle mass and respiratory muscle strength and enduranee (40). These effects on the respiratory muscles are partially reversible with nutritional support. The process, however, is slow, and in laboratory animals, it can take months of refeeding for muscle mass to return to normal values (72). To date, it remains unclear whether malnutrition by itself ean cause sufficient respiratory muscle weakness to produce ventilator dependence. It is more likely for malnutrition to be a contributing factor and not a sole cause of ventilator dependence. 

Nutritional status is crucial in the care of ventilated patients, as malnutrition reduces respiratory muscle mass and contributes to failure to wean from PMV (22-25). Therefore,... 

Cancer results in anorexia (lack of interest in eating), malnutrition, and weight loss. Although weight loss may be due to loss of muscle and organ tissue (lean body mass), as well as of fat, the loss of fat is a minimal concern in cancer and other wasting diseases. Cachexia is a term that is often used to n fer to the wasting of muscle and other tissues that occurs with various diseases. 

Prealbumin and retinol-binding protein, traditionally sensitive markers of protein-energy malnutrition, may not be as reliable in patients with hepatic failure. Liver failure can cause decreased concentrations of both, independent of nutritional status. Indeed, many of the commonly used markers of nutritional status correlate poorly with body cell mass in those with end-stage liver disease. Midarm muscle circumference and handgrip strength have been found to be the best... 

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