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ABSTRACT: Type 2 diabetes is characterized by progressive beta-cell failure. Indications for exogenous insulin therapy in patients with this condition include acute illness or surgery, pregnancy, glucose toxicity, contraindications to or failure to achieve goals with oral antidiabetic medications, and a need for flexible therapy. Augmentation therapy with basal insulin is useful if some beta-cell function remains. Replacement therapy with basal-bolus insulin is required for beta-cell exhaustion. Rescue therapy using replacement regimens for several weeks may reverse glucose toxicity. Replacement insulin therapy should mimic normal release patterns. Basal insulin, using long-acting insulins (i.e., neutral protamine Hagedorn [NPH], ultralente, glargine) is injected once or twice a day and continued on sick days. Bolus (or mealtime) insulin, using short-acting or rapid-acting insulins (i.e., regular, aspart, lispro) covers mealtime carbohydrates and corrects the current glucose level. The starting dose of 0.15 units per kg per day for augmentation or 0.5 units per kg per day for replacement can be increased several times as needed. About 50 to 60 percent of the total daily insulin requirement should be a basal type, and 40 to 50 percent should be a bolus type. The mealtime dose is the sum of the corrective dose plus the anticipated requirements for the meal and exercise. Adjustments should be made systematically, starting with the fasting, then the preprandial and, finally, the postprandial glucose levels. Basal therapy with glargine insulin provides similar to lower A1C levels with less hypoglycemia than NPH insulin. Insulin aspart and insulin lispro provide similar A1C levels and quality of life, but lower postprandial glucose levels than regular insulin.
ABSTRACT: Despite exhaustive efforts to better manage patients with type 2 diabetes mellitus (formerly known as non-insulin-dependent diabetes mellitus), attempts at maintaining near normal blood glucose levels in these patients remains unsatisfactory. This continues to pose a real challenge to physicians as the prevalence of this disease in the United States continues to rise. Type 2 diabetes is defined as a syndrome characterized by insulin deficiency, insulin resistance and increased hepatic glucose output. Medications used to treat type 2 diabetes are designed to correct one or more of these metabolic abnormalities. Currently, there are five distinct classes of hypoglycemic agents available, each class displaying unique pharmacologic properties. These classes are the sulfonylureas, meglitinides, biguanides, thiazolidinediones and alpha-glucosidase inhibitors. In patients for whom diet and exercise do not provide adequate glucose control, therapy with a single oral agent can be tried. When choosing an agent, it is prudent to consider both patient- and drug-specific characteristics. If adequate blood glucose control is not attained using a single oral agent, a combination of agents with different mechanisms of action may have additive therapeutic effects and result in better glycemic control.
Perioperative Management of Diabetes - Article
ABSTRACT: Maintaining glycemic and metabolic control is difficult in diabetic patients who are undergoing surgery. The preoperative evaluation of all patients with diabetes should include careful screening for asymptomatic cardiac or renal disease. Frequent self-monitoring of glucose levels is important in the week before surgery so that insulin regimens can be adjusted as needed. Oral agents and long-acting insulin are usually discontinued before surgery, although the newer long-acting insulin analog glargine may be appropriately administered for basal insulin coverage throughout the surgical period. The usual regimen of sliding scale subcutaneous insulin for perioperative glycemic control may be a less preferable method because it can have unreliable absorption and lead to erratic blood glucose levels. Intravenous insulin infusion offers advantages because of the more predictable absorption rates and ability to rapidly titrate insulin delivery up or down to maintain proper glycemic control. Insulin is typically infused at 1 to 2 U per hour and adjusted according to the results of frequent blood glucose checks. A separate infusion of dextrose prevents hypoglycemia. Potassium is usually added to the dextrose infusion at 10 to 20 mEq per L in patients with normal renal function and normal preoperative serum potassium levels. Frequent monitoring of electrolytes and acid-base status is important during the perioperative period, especially in patients with type 1 diabetes because ketoacidosis can develop at modest levels of hyperglycemia.
ABSTRACT: Impaired glucose tolerance and impaired fasting glucose form an intermediate stage in the natural history of diabetes mellitus. From 10 to 15 percent of adults in the United States have one of these conditions. Impaired glucose tolerance is defined as two-hour glucose levels of 140 to 199 mg per dL (7.8 to 11.0 mmol) on the 75-g oral glucose tolerance test, and impaired fasting glucose is defined as glucose levels of 100 to 125 mg per dL (5.6 to 6.9 mmol per L) in fasting patients. These glucose levels are above normal but below the level that is diagnostic for diabetes. Patients with impaired glucose tolerance or impaired fasting glucose have a significant risk of developing diabetes and thus are an important target group for primary prevention. Risk factors for diabetes include family history of diabetes, body mass index greater than 25 kg per m2, sedentary lifestyle, hypertension, dyslipidemia, history of gestational diabetes or large-for-gestational-age infant, and polycystic ovary syndrome. Blacks, Latin Americans, Native Americans, and Asian-Pacific Islanders also are at increased risk for diabetes. Patients at higher risk should be screened with a fasting plasma glucose level. When the diagnosis of impaired glucose tolerance or impaired fasting glucose is made, physicians should counsel patients to lose 5 to 7 percent of their body weight and engage in moderate physical activity for at least 150 minutes per week. Drug therapy with metformin or acarbose has been shown to delay or prevent the onset of diabetes. However, medications are not as effective as lifestyle changes, and it is not known if treatment with these drugs is cost effective in the management of impaired glucose tolerance.
Hyperosmolar Hyperglycemic State - Article
ABSTRACT: Hyperosmolar hyperglycemic state is a life-threatening emergency manifested by marked elevation of blood glucose, hyperosmolarity, and little or no ketosis. With the dramatic increase in the prevalence of type 2 diabetes and the aging population, this condition may be encountered more frequently by family physicians in the future. Although the precipitating causes are numerous, underlying infections are the most common. Other causes include certain medications, non-compliance, undiagnosed diabetes, substance abuse, and coexisting disease. Physical findings of hyperosmolar hyperglycemic state include those associated with profound dehydration and various neurologic symptoms such as coma. The first step of treatment involves careful monitoring of the patient and laboratory values. Vigorous correction of dehydration with the use of normal saline is critical, requiring an average of 9 L in 48 hours. After urine output has been established, potassium replacement should begin. Once fluid replacement has been initiated, insulin should be given as an initial bolus of 0.15 U per kg intravenously, followed by a drip of 0.1 U per kg per hour until the blood glucose level falls to between 250 and 300 mg per dL. Identification and treatment of the underlying and precipitating causes are necessary. It is important to monitor the patient for complications such as vascular occlusions (e.g., mesenteric artery occlusion, myocardial infarction, low-flow syndrome, and disseminated intravascular coagulopathy) and rhabdomyolysis. Finally, physicians should focus on preventing future episodes using patient education and instruction in self-monitoring.
Diabetic Ketoacidosis - Article
ABSTRACT: A diagnosis of diabetic ketoacidosis requires the patient's plasma glucose concentration to be above 250 mg per dL (although it usually is much higher), the pH level to be less than 7.30, and the bicarbonate level to be 18 mEq per L or less. Beta-hydroxybutyrate is a better measurement of the degree of ketosis than serum ketones. Intravenous insulin and fluid replacement are the mainstays of therapy, with careful monitoring of potassium levels. Phosphorous and magnesium also may need to be replaced. Bicarbonate therapy rarely is needed. Infection, insulin omission, and other problems that may have precipitated ketoacidosis should be treated. Myocardial infarction is a precipitating cause of diabetic ketoacidosis that is especially important to look for in older patients with diabetes. Cerebral edema is a major complication that occurs primarily in children. Education to prevent recurrence should be offered to all patients, including how to manage sick days and when to call a physician.
ABSTRACT: The American Diabetes Association currently recommends an A1C goal of less than 7 percent. However, many patients are unable to achieve this goal by using oral drug combinations or diet and exercise, leaving insulin as the only treatment option. In most cases, insulin is initiated later in therapy because of its inconvenience and adverse effects (e.g., weight gain, hypoglycemia, possible role in atherogenesis). Although insulin effectively helps patients attain glucose goals, the search for new agents continues. Two injectable agents, pramlintide and exenatide, were approved in 2005 for the treatment of diabetes. Pramlintide, indicated for use in patients with type 1 and 2 diabetes, is a synthetic analogue of human amylin that acts in conjunction with insulin to delay gastric emptying and inhibit the release of glucagon. Exenatide, a glucagon-like peptide-1 mimetic, has multiple mechanisms for lowering glucose levels, including the enhancement of insulin secretion, and is indicated for use in patients with type 2 diabetes. Clinical trials have shown that both agents reduce, by a statistically significant degree, A1C levels (0.3 to 0.7 percent more than placebo), fasting plasma glucose levels, and body weight (3 to 5 lb [1.4 to 2.3 kg]). No studies have examined their effects on diabetic complications, cardiovascular disease, or overall mortality. Pramlintide and exenatide may help make glycemic goals more attainable.
ABSTRACT: Herbs, vitamins, and other dietary supplements may augment or antagonize the actions of prescription and nonprescription drugs. St. John's wort is the supplement that has the most documented interactions with drugs. As with many drug-drug interactions, the information for many dietary supplements is deficient and sometimes supported only by case reports. Deleterious effects are most pronounced with anticoagulants, cardiovascular medications, oral hypoglycemics, and antiretrovirals. Case reports have shown a reduction in International Normalized Ratio in patients taking St. John's wort and warfarin. Other studies have shown reduced levels of verapamil, statins, digoxin, and antiretrovirals in patients taking St. John's wort. Physicians should routinely ask patients about their use of dietary supplements when starting or stopping a prescription drug, or if unexpected reactions occur.
ABSTRACT: Research has established the importance of maintaining blood glucose levels near normal in patients with type 1 (insulin-dependent) diabetes mellitus. Short-acting insulin analogs are designed to overcome the limitations of regular short-acting insulins. Compared with regular human insulin, the analog insulin lispro offers faster subcutaneous absorption, an earlier and greater insulin peak and a more rapid postpeak decrease. Insulin lispro begins to exert its effects within 15 minutes of subcutaneous administration, and peak levels occur 30 to 90 minutes after administration. Duration of activity is less than five hours. Rates of insulin allergy, lipodystrophy, hypoglycemia and abnormal laboratory test results are essentially the same in patients using insulin lispro and in those using regular human insulin.
ABSTRACT: Subopitmal glycemic control in hospitalized patients with type 2 (non-insulin-dependent) diabetes mellitus can have adverse consequences, including increased neurologic ischemia, delayed wound healing and an increased infection rate. Poor glycemic control can also affect the outcome of the primary illness. If possible, hospitalized diabetic patients should continue their previous antihyperglycemic treatment regimen. Decreased physical activity and the stress of illness often lead to hyperglycemia in hospitalized patients with type 2 diabetes. When indicated, insulin is given either as a supplement to usual therapy or as a temporary substitute. The overall benefit of the traditional sliding-scale insulin regimen has been questioned. Insulin supplementation given according to an algorithm may be a logical alternative. Any antihyperglycemic regimen should be administered and monitored in a manner coincident with the intake of food or other sources of calories. Factors that can alter glycemic control acutely, including specific medical conditions and medications, should be identified and anticipated.