Diabetes Mellitus

Diabetes mellitus comes from the Greek word "diabainein" meaning "to pass through," and the Latin word "mellitus" meaning "sweetened with honey." Put the two words together and you have "to pass through sweetened with honey."

Diabetes mellitus is a serious, chronic disease of absolute or relative insulin deficiency or resistance that's characterized by disturbances in carbohydrate, protein, and fat metabolism. A leading cause of death by disease in the United States, this syndrome is a contributing factor in about 50% of myocardial infarctions and about 75% of strokes as well as in renal failure and Peripheral vascular disease.It's also the leading cause of new blindness. Diabetes mellitus affects an estimated 6.2% of the population of the United States (17 million people); more than 50% are women.

As women are living longer and more minority women are entering the United States, the number of women at high risk for diabetes and its complications will increase.

Diabetes mellitus occurs in four forms classified by etiology: type 1, type 2, other specific types, and gestational diabetes mellitus (GDM). Type 1 is further subdivided into immune mediated diabetes and idiopathic diabetes. Children and adolescents with type 1 immune-mediated diabetes rapidly develop ketoaddosis, but most adults with this type experience only modest fasting hyperglYCemia unless they develop an infection or experience another stressor. Patients with type 1 idiopathic diabetes are prone to ketoaddosis.

About 90% to 95% of women with diabetes have type 2. Those who were previously in the type 2 or non insulin-dependent diabetes (NIDDM) diabetes group also fall into this category. The "other specific types" category includes people who have diabetes because of a genetic defect, endocrinopathies, or exposure to certain drugs or chemicals.

GDM only occurs during pregnancy. It usually ends after the baby is born, but women with GDM have up to a 45% risk of recurrence in the next pregnancy and up to a 63% risk of developing type 2 diabetes later in life.

What causes diabetes mellitus ?

In type 1 diabetes, pancreatic beta-cell destruction or a primary defect in beta-cell function results in failure to release insulin and ineffective glucose transport. Type 1 immune-mediated diabetes is caused by cell-mediated destruction of pancreatic beta cells. The rate of beta-cell destruction is usually higher in children than in adults. The idiopathic form of type 1 diabetes has no known cause. Patients with this form have no evidence of auto immunity and don't produce insulin.

In type 2 diabetes, beta cells release insulin, but receptors are insulin-resistant and glucose transport is variable and ineffective. Risk factors for type 2 diabetes include:

• obesity (even just an increased percentage of body fat primarily in the abdominal region); risk decreases with weight loss and drug therapy
• lack of physical activity
• history of GDM
• hypertension or dyslipidemia
• Black, Latino, or Native American origin
• strong family history of diabetes
• increasing age (usually develops in women over age 40).

As the body ages, the cells become more resistant to insulin, thus reducing the older adult's ability to metabolize glucose. In addition, the release of insulin from the pancreatic beta cells is reduced and delayed. These combined processes result in hyperglycemia. In the older patient, sudden concentrations of glucose cause increased and more prolonged hyperglycemia.

Other types of diabetes mellitus result from various conditions (such as a genetic defect of the beta cells or endocrinopathies). They may also result from use of or exposure to certain drugs or chemicals.

GDM is considered present whenever a woman has any degree of abnormal glucose during pregnancy. This form may result from weight gain and increased levels of estrogen and placental hormones, which antagonize insulin. During pregnancy, the fetus relies on maternal glucose as a primary fuel source. Pregnancy triggers protective mechanisms that have anti-insulin effects: increased hormone production (placental lactogen, estrogen, and progesterone), which antagonizes the effects of insulin; degradation of insulin by the placenta; and prolonged elevation of stress hormones (cortisol, epinephrine, and glucagon), which raise blood glucose levels.

In a normal pregnancy, an increase in anti-insulin factors is counterbalanced by an increase in insulin production to maintain normal blood glucose levels. However, females who are prediabetic or diabetic are unable to produce sufficient insulin to overcome the insulin antagonist mechanisms of pregnancy, or their tissues are insulin resistant. As insulin requirements rise toward term, the patient who is prediabetic may develop GDM, necessitating dietary management and, possibly, exogenous insulin to achieve glycemic control, whereas the patient who is insulin dependent may need increased insulin dosage. In GDM, glucose tolerance levels usually return to normal after delivery. However, children who are exposed to diabetes in the womb have a greater likelihood of becoming obese during childhood ;.nd adolescence and developing type 2 diabetes later in life.

Symptoms of diabetes mellitus

Diabetes may begin dramatically with ketoacidosis or insidiously. Its most common symptom is fatigue from energy deficiency and a catabolic state. Insulin deficiency causes hyperglycemia. which pulls fluid from body tissues, causing osmotic diuresis, polyuria, dehydration, polydipsia, dry mucous membranes, poor skin turgor and, in most patients, unexplained weight loss.

In ketoacidosis and hyperosmolar hyperglycemic nonketotic syndrome, dehydration may cause hypovolemia and shock. Wasting of glucose in the urine usually produces weight loss and hunger in type 1 diabetes, even if the patient eats voraciously.

Long-term complications of diabetes may include retinopathy, nephropathy, atherosclerosis, and peripheral and autonomic neuropathy. Peripheral neuropathy usually affects the hands and feet and may cause numbness or pain. Autonomic neuropathy may manifest itself in several ways, including gastroparesis leading to delayed gastric emptying and a feeling of nausea and fullness after meals), nocturnal diarrhea, impotence, and orthostatic hypotension.

Heart disease is the most common complication of diabetes. Although more men with diabetes suffer from heart disease, it's more serious among women because they have lower survival rates and suffer a poorer quality of life than men. In addition, women with diabetes have a shorter life expectancy than women without diabetes (almost threefold). They are also at greater risk for blindness from diabetes than men with the disorder. Because hyperglycemia impairs the patient's resistance to infection, diabetes may also result in skin and urinary tract infections and vaginitis. Glucose content of the epidermis and urine encourages bacterial growth.

Diagnosis information

The gold standard for diagnosis of diabetes used to be the 2-hourplasma glucose test; however, the fasting plasma glucose (FPG) is also recommended because it's easier (no waiting and better tolerated), has better reproducibility and reliability, and has lower costs.Also, there's inadequate evidence to show that either test is superior.

According to the American Diabetes Association's (ADA) latest guidelines, diabetes mellitus can be diagnosed if any of the following exist:

• symptoms of diabetes (polyuria, polydipsia, unexplained weight loss) plus a casual plasma glucose value (obtained without regard to the time of the patient's last food intake) greater than or equal to 200 mg/dl
• fasting plasma glucose level (no caloric intake for at least 8 hours) greater than or equal to 126 mg/dl
• plasma glucose value in the 2-hour sample of the oral glucose tolerance test greater than or equal to 200 mg! dl. This test should be performed after a glucose load dose of 75 g of anhydrous glucose.
  To confirm suspected GDM, a screening 50-gram, 1-hour glucose tolerance test is normally performed at 24 to 28 weeks' gestation. In addition, women with a history of fetal macrosomia or who may have nongestational diabetes should be formally tested for diabetes with a 3-hour glucose tolerance test. A 100-gram, 3-hour glucose tolerance test confirms diabetes mellitus when two or more values are above normal.

If any results are questionable, the diagnosis should be confirmed by a repeat test on a different day. The ADA also recommends the following testing guidelines:

• In patients with newly diagnosed diabetes, a confirmatory test is recommended after the initial test.
• Test people age 45 or older without symptoms every 3 years.
• Test people with the classic symptoms immediately.
• Those with an abnormal FPG should have a 2-hour plasma glucose test.

Note: Individuals with IGT usually have normal blood levels unless challenged by a glucose load, such as a piece of pie or glass of orange juice. Two hours after a glucose load, the glucose level ranges from 140 to 199 mg/dl. Individuals with IFG have an abnormal fasting glucose level between 110 and 125 mg/dl. Because the fasting plasma glucose test is sufficient to make the diagnosis of diabetes, it replaces the oral glucose tolerance test.

An ophthalmologic examination may show diabetic retinopathy. Other diagnostic and monitoring tests include urinalysis for acetone and blood testing for glycosylated hemoglobin (hemoglobin A), which reflects recent glucose cortisol.

Treatment of diabetes mellitus

Effective treatment normalizes blood glucose and decreases complications. In diabetes type 1, this goal is achieved with insulin replacement, diet, and exercise. Current forms of insulin replacement include single dose, mixed-dose, split-mixed dose, and multiple-dose regimens. The multiple-dose regimens may use an insulin pump. Insulin may be very rapid-acting (Humalog, Novo Log), rapid-acting (Ve1osulin, Regular), Intermediate-acting (NPH), longacting (llitralente), or a combination of rapid-acting and intermediate-acting (MIxtard); standard or purified; and derived from beef, pork, or human sources. Purified human insulin is most commonly used.

Pancreas transplantation is experimental and requires chronic immunosuppression. Islet cell transplantation Is another experimental treatment option that is less complicated than whole pancreas transplantation, but also requires chronic immunosuppression.

Treatment of all types of diabetes also requires a strict diet planned to meet nutritional needs, to control blood glucose levels, and to reach and maintain appropriate body weight. For the obese patient with type 2 diabetes, weight reduction Is a goal. In type 1 diabetes, the calorie allotment may be high, depending on growth stage and activity level. For success, the diet must be followed consIstently and meals eaten at regular times.

type 2 diabetes may require oral antidiabetic drugs to stimulate endogenous insulin production, increase insulin sensitivity at the cellular level, and suppress hepatic gluconeogenesis:

Five types of drugs have been used to treat diabetes. Sulfonylureas (such as tolbutamide [Orinase)) stimulate pancreatic insulin release, increase tissue sensitivity to insulin, and require insulin's presence to work.

Repaglinide (Prandin) and nateglinide (Starllx) cause immedIate, briefrelease of insulin and are taken immediately before meals. Biguanides (such as metformin [Glucophage]) decrease hepatic glucose production and increase tissue sensitivity to insulin. Alpha-glucosidase inhibitors (such as acarbose [Precose)) slow the breakdown of glucose and decrease postprandial glucose peaks. The thiazolidinediones (such as roglltazone [Avandia)) enhance the action of insulin; however, insulin must be present for them to work. These drugs also reduce insulin resistance by decreasing hepatic glucose production and increasing glucose uptake. They have also been shown to lower blood pressure in diabetic hypertensive patients. Cholesterol and triglyceride levels may also be reduced.

Treatment of long-term diabetic complications may include transplantation or dialysis for renal failure, photocoagulation for retinopathy, and vascular surgery for large-vessel disease. Meticulous blood glucose control is essential.

Any patient with a wound that has lasted more than 8 weeks and who has tried standard wound care and revascularization without improvement should consider hyperbaric oxygen therapy. This treatment may speed healing by allowing more oxygen to get to the wound and may therefore result in fewer amputations.

The Diabetes Control and Complications Trial has shown that, in type 1 diabetes, intensive drug therapy that focuses on keeping glucose at near normal levels for 5 years or more reduces both the onset and progression of retinopathy (up to 63%), nephropathy (up to 54%), and neuropathy (up to 60%). The United Kingdom Diabetes Study Group demonstrated that in type 2 diabetes, blood pressure control as well as smoking cessation reduced the onset and progression of complications, including cardiovascular disease.

Special considerations or prevention

• Stress the importance of complying with the prescribed treatment program. Tailor your teaching to the patient's needs, abilities, and developmental stage. Include diet; purpose,administration, and possible adverse effects of medication; exercise; monitoring; hygiene; and the prevention and recognition of hypoglycemia and hyperglycemia. Stress the effect of blood glucose control on long-term health.
• Watch for acute complications of diabetic therapy, especially hypoglycemia (vagueness, slow cerebration,dizziness, weakness, pallor, tachycardia, diaphoresis, seizures, and coma); immediately give carbohydrates, ideally in the form of fruit juice. hard candy, honey, or glucose tablets or gels, if available. If the patient is unconscious, administer glucagon or dextrose I. V. Also, be alert for signs of ketoacidosis (acetone breath, dehydration, weak and rapid pulse, Kussmaul's respirations) and hyperosmolar coma (polyuria, thirst, neurologic abnormalities, stupor). These hyperglycemic crises require I.V. fluids, insulin and usually, potassium replacement.
• Monitor diabetes control by obtaining blood glucose, glycohemoglobulin, lipid levels, and blood pressure measurements regularly.
• Watch for diabetic effects on the cardiovascular system, such as cerebrovascular, coronary artery, and peripheral vascular impairment, and on the peripheral and autonomic nervous systems. Treat all injuries, cuts, and blisters (particularly on the legs or feet) meticulously. Be alert for signs of urinary tract infection and renal disease.
• Urge regular ophthalmologic examinations to detect diabetic retinopathy. . Assess for signs of diabetic neuropathy (numbness or pain in hands and feet, foot drop, neurogenic bladder).Stress the need for personal safety precautions because decreased sensation can mask injuries. Minimize complications by maintaining strict blood glucose control.
• Teach the patient to care for her feet by washing them daily, drying carefully between toes, and inspecting for corns, calluses, redness, swelling, bruises, and breaks in the skin. Urge her to report any changes to the physician. Advise her to avoid wearing con
  stricting shoes or walking barefoot. Instruct her to use over-the-counter athlete's foot remedies and seek professional care should athlete's foot not improve.
• Teach the patient how to manage her diabetes when she has a minor illness, such as a cold, the flu, or an upset stomach.
• To delay the clinical onset of diabetes, teach people at high risk to avoid risk factors. Advise genetic counseling for young adults with diabetes who are planning families.
• Maintaining an ideal body weight and an active lifestyle may prevent the onset of type 2 diabetes.