الفهرس 
Surgical management of morbid obesityOnly 14 pages are availabe for public view
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Abstract
Recent statistics indicate that overweight and obesity have become an increasingly serious clinical and socioeconomic problem worldwide, and one of the greatest public health challenges of our time. The International Obesity Task Force estimates that worldwide at least 1.1 billion adults are overweight, including 312 million who are obese. Overweight and obese patients are at an increased risk for developing numerous cardiometabolic complications, including hypertension, type 2 diabetes mellitus, dyslipidemia, and cardiovascular diseases, as well as conditions such as osteoarthritis, obstructive sleep apnea, hepatobiliary diseases, and certain types of cancers.
Recent evidence shows that bariatric surgery for severe obesity is associated with decreased overall mortality. However, serious complications can occur and therefore a careful selection of patients is of utmost importance. Bariatric surgery should at least be considered for all patients with a BMI of more than 40 kg/m2 and for those with a BMI of more than 35 kg/m2 with concomitant obesity-related conditions after failure of conventional treatment.
The increasing prevalence of obesity and type 2 diabetes mellitus (T2DM) worldwide may nowadays be regarded as a ”twin” metabolic pandemic, causing the number of patients with the metabolic syndrome (MS) to rise rapidly. MS is a combination of several interrelated medical disorders such as obesity, T2DM, hypertension, dyslipidaemia etc. Bariatric, also referred to as metabolic (B-M) surgery currently represents a very powerful method for the treatment of morbid obesity and the metabolic syndrome.
Changes in the anatomy and function of the gastrointestinal tract after gastric bypass markedly change patients’ eating patterns. Malnutrition is a significant risk associated with all bariatric procedures, which can lead to dangerous nutritional deficiencies.
Most of the patients undergoing malabsorptive procedures will develop some nutritional deficiency, justifying mineral and multivitamin supplementation to all postoperatively. Nutrient deficiency is proportional to the length of absorptive area and to the percentage of weight loss. Low levels of iron, vitamin B12, vitamin D and calcium are predominant after Roux-en-Y gastric bypass. Protein and fat-soluble vitamin deficiencies are mainly detected after biliopancreatic diversion. Thiamine deficiency is common in patients with frequent vomiting. As the incidence of these deficiencies progresses with time, the patients should be monitored frequently and regularly to prevent malnutrition.
It has been suggested that, besides the restriction imposed by the surgical procedure, alterations in gut regulatory peptides signaling the brain might contribute.
Patients following Roux-en-Y gastric bypass (RYGB) had increased postprandial plasma PYY and GLP-1 favoring enhanced satiety. Furthermore, RYGB patients had early and exaggerated insulin responses, potentially mediating improved glycemic control.
Several mechanisms are proposed to explain the improvement in glucose metabolism after RYGB surgery: the caloric restriction and weight loss per se, the improvement in insulin resistance and beta cell function, and finally the alterations in the various gastrointestinal hormones and adipokines that have been shown to play an important role in glucose homeostasis.
RYGB provides anti-diabetic effects through decreasing insulin resistance and increasing the efficiency of insulin secretion, this achieved through weight-independent and weight dependent mechanisms including foregut, midgut and hindgut mechanisms.
Several biological features of glucagon-like peptide 1 (GLP-1) have led to propose this peptide hormone as an ideal candidate for the treatment of diabetes by lowering postprandial hyperglycemia via three independent mechanisms: increases insulin secretion, inhibits glucagon release, and inhibits gastrointestinal motility.
Studies evaluating hormonal changes after RYGB surgery have shown an overall positive change in hormones, favoring glycemic control. The orexigenic peptide ghrelin is reduced, while the anorexigenic GLP-1, oxyntomodulin, and PYY are increased. Hormones such as Leptin, amylin, GIP, and insulin, to which a suggested state of resistance is observed in obesity and T2D tend to decrease, favor a restored homeostasis.