الفهرس 
Pathophysiology and Biochemical Background of Diabetes MellitusOnly 14 pages are availabe for public view
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Abstract
Diabetes mellitus is becoming one of the world’s biggest health problems owing to the projected increase in new cases, it is inevitable that the number of diabetic patients presenting for surgery also increases which makes understanding of its pathophysiology, complications and perioperative management essential for any anesthesiologist.
The term diabetes mellitus describes a metabolic disorder of multiple etiologies characterized by chronic hyperglycemia with disturbances of carbohydrate, fat and protein metabolism resulting from defects in insulin secretion, action or both.
Glucose regulation is under control of many hormones both pancreatic and gut that exert effect on multiple target tissues, such as muscle, brain, liver and adipocyte.
There are three criteria used to make a diagnosis of diabetes; elevated fasting glucose, abnormal oral glucose tolerance test (OGTT) or symptoms of diabetes with hyperglycemia two or more values must be met or exceeded for a diagnosis.
Microvascular, neuropathic and macrovascular complications of diabetes mellitus are of special concern for the anesthetist. Of particular importance are coronary heart disease, diabetic nephropathy and autonomic neuropathy because these may have a direct effect on the development of perioperative complications while Diabetic ketoacidosis (DKA) and hyperglycaemic hyperosmolar state (HHS) are the major hyperglycaemic crises associated with diabetes mellitus.
New guidelines has been postulated for the management of diabetic patients throughout surgical interference as tight glycemic control in diabetic patients undergoing major surgery has been shown to improve perioperative morbidity and mortality rates. However, this aggressive strategy requires frequent monitoring of blood glucose concentrations as surgery induces a considerable stress response mediated by the neuroendocrine system through the release of catecholamines, glucagon and cortisol which results in peripheral insulin resistance, increased hepatic glucose production, impaired insulin secretion, fat and protein breakdown and potential hyperglycemia and even ketosis in some cases.
The preoperative assessment of diabetic patients must be meticulous and in addition to the usual medical history and examination the type, duration, presence of any complications and current treatment of diabetes must be established also carefull cardiac assessment because of high risk of coronary heart disease.
The regimen selected to manage diabetics undergoing surgery has become standardized in most facilities in recent years with a target glucose and maintenance in the range of 80-110 mg/dl but still the key to success of any regimen is careful frequent monitoring to detect any alterations in metabolic control and correct them before they become severe.
While sliding-scale use of subcutaneous insulin has long been a standard method of glucose control in hospitalized patients many diabetes authorities have recently promoted the use of a variable-rate intravenous (IV) insulin infusion as a more effective approach to perioperative diabetic management especially after Use of continuous glucose monitoring systems as they become more widely available making the difficulties of performing frequent glucose measurements obsolete.