VOL. 18 NO. 3 Summer 2000
R.C. is a 57-year-old man with type 2 diabetes first diagnosed 2 years ago. Other medical problems include obesity and hypothyroidism. He has a history of heavy alcohol use but quit drinking alcohol 2 years ago. He presents now for routine follow-up and is noted to have a blood pressure of 168/100 mmHg. He is asymptomatic.
Physical exam reveals a height of 5 feet, 8 inches, weight of 243 lb, blood pressure of 160/100 mmHg, and a regular pulse of 84 beats/min. There is no retinopathy or thyromegaly. There is no clinical evidence of congestive heart failure or peripheral vascular disease.
Laboratory evaluation reveals trace protein on urinalysis, blood urea nitrogen of 14 mg/dl, serum creatinine of 1.2 mg/dl, random serum glucose of 169 mg/dl, normal electrolytes, and normal thyroid-stimulating hormone levels. A 24-h urine collection reveals a urinary albumin excretion rate of 250 mg/day.
- Does this patient have renal disease?
- Should his blood pressure be treated?
- What treatment strategy should be used?
Diabetic nephropathy is a clinical syndrome characterized by albuminuria, hypertension, and progressive renal insufficiency. Diabetic nephropathy is the most common cause of end-stage renal disease (ESRD) in Western countries, accounting for ~35% of all new ESRD cases in the United States. The life expectancy of patients with diabetic ESRD is <50% at 3 years, despite improvements in dialysis and renal transplantation.
Early detection and treatment of albuminuria is essential in diabetes. A normal urinary albumin excretion rate (UAER) ranges from 0 to 30 mg/day. Overt albuminuria or macroalbuminuria is defined as a UAER >300 mg/day. Many studies have shown that a UAER >30 mg/day is abnormal and can be used to predict the development of overt albuminuria or diabetic nephropathy and both microvascular and macrovascular disease. As a result, the term "microalbuminuria" was coined to refer to a UAER of 30299 mg/day.
Many organizations, including the American Diabetes Association, recommend regular screening for microalbuminuria. Type 1 diabetic patients should be screened 5 years after diagnosis of diabetes and after puberty. People with type 2 diabetes should be screened from the time of diagnosis, since many type 2 diabetic patients have had undiagnosed disease for some time. If the initial screening is negative, then annual screenings are indicated.
Traditional urinary dipsticks are insensitive at detecting albuminuria <300 mg/day. Spot urine samples may be assayed for microalbuminuria and creatinine and a ratio >30 �g/mg or mg/g is abnormal. Newer methods, such as Micral-Test II test strips (Boehringer Mannheim, Mannheim, Germany), permit reliable semiquantitative determination of microalbuminuria and can be used in the office for dipstick screening of diabetic patients.
Transient elevations in urinary albumin excretion may be associated with marked hyperglycemia, acute febrile illness, exercise, hypertension, heart failure, and urinary tract infection. If the initial test is elevated, these and other potential causes of renal disease should be considered and ruled out. Because there is also marked day-to-day variability in urinary albumin excretion, a positive test should be confirmed on a subsequent occasion before designating a patient as having persistent microalbuminuria.
Patients identified with persistent microalbuminuria should be aggressively treated both with respect to glycemic and blood pressure control. Patients are considered to be hypertensive if their blood pressure is >140/90 mmHg. The goal for the management of hypertensive diabetic patients is to keep the blood pressure <130/85 mmHg.
The treatment of choice for hypertensive diabetic patients with or without microalbuminuria remains angiotensin-converting enzyme (ACE) inhibitors. Only captopril (Capoten) is approved for the treatment of diabetic nephropathy, but all ACE inhibitors appear to be effective. Fosinopril (Monopril) has a dual route of elimination and therefore may have an advantage over other ACE inhibitors, particularly when used for patients with renal insufficiency or failure.
Once started, renoprotective therapy should be continued indefinitely. ACE inhibitors have been shown to prevent or slow the progression from microalbuminuria to overt nephropathy. Studies have also shown that the renoprotective effects of ACE inhibitors go beyond those expected from blood pressure reduction by itself. Additionally, the renoprotective effects apply to both normotensive and hypertensive patients with microalbuminuria. Therefore, the indication for ACE inhibition can be persistent microalbuminuria, regardless of blood pressure. Discontinuing therapy will result in a recurrence of microalbuminuria.
In addition to aggressively managing blood pressure, attempts need to be made toward lifestyle modifications. These include meticulous control of blood glucose, seeking counseling to stop smoking, maintaining optimal body weight, following an appropriate diet, and exercising regularly.
- Screen diabetic patients for microalbuminuria.
- Recognize hypertension in diabetic patients with a blood pressure >140/90 mmHg.
- ACE inhibition is the preferred treatment of microalbuminuria and/or hypertension.
- Counsel diabetic patients on lifestyle modifications, including blood glucose control, weight control, smoking cessation, diet, and exercise
Diabetes mellitus is a condition in which the pancreas no longer produces enough insulin or cells stop responding to the insulin that is produced, so that glucose in the blood cannot be absorbed into the cells of the body. Symptoms include frequent urination, lethargy, excessive thirst, and hunger. The treatment includes changes in diet, oral medications, and in some cases, daily injections of insulin.
The most common form of diabetes is Type II, It is sometimes called age-onset or adult-onset diabetes, and this form of diabetes occurs most often in people who are overweight and who do not exercise. Type II is considered a milder form of diabetes because of its slow onset (sometimes developing over the course of several years) and because it usually can be controlled with diet and oral medication. The consequences of uncontrolled and untreated Type II diabetes, however, are the just as serious as those for Type I. This form is also called noninsulin-dependent diabetes, a term that is somewhat misleading. Many people with Type II diabetes can control the condition with diet and oral medications, however, insulin injections are sometimes necessary if treatment with diet and oral medication is not working.
The causes of diabetes mellitus are unclear, however, there seem to be both hereditary (genetic factors passed on in families) and environmental factors involved. Research has shown that some people who develop diabetes have common genetic markers. In Type I diabetes, the immune system, the body’s defense system against infection, is believed to be triggered by a virus or another microorganism that destroys cells in the pancreas that produce insulin. In Type II diabetes, age, obesity, and family history of diabetes play a role.
In Type II diabetes, the pancreas may produce enough insulin, however, cells have become resistant to the insulin produced and it may not work as effectively. Symptoms of Type II diabetes can begin so gradually that a person may not know that he or she has it. Early signs are lethargy, extreme thirst, and frequent urination. Other symptoms may include sudden weight loss, slow wound healing, urinary tract infections, gum disease, or blurred vision. It is not unusual for Type II diabetes to be detected while a patient is seeing a doctor about another health concern that is actually being caused by the yet undiagnosed diabetes.
Individuals who are at high risk of developing Type II diabetes mellitus include people who:
- are obese (more than 20% above their ideal body weight)
- have a relative with diabetes mellitus
- belong to a high-risk ethnic population (African-American, Native American, Hispanic, or Native Hawaiian)
- have been diagnosed with gestational diabetes or have delivered a baby weighing more than 9 lbs (4 kg)
- have high blood pressure (140/90 mmHg or above)
- have a high density lipoprotein cholesterol level less than or equal to 35 mg/dL and/or a triglyceride level greater than or equal to 250 mg/dL
- have had impaired glucose tolerance or impaired fasting glucose on previous testing
Diabetes mellitus is a common chronic disease requiring lifelong behavioral and lifestyle changes. It is best managed with a team approach to empower the client to successfully manage the disease. As part of the team the, the nurse plans, organizes, and coordinates care among the various health disciplines involved; provides care and education and promotes the client’s health and well being. Diabetes is a major public health worldwide. Its complications cause many devastating health problems.
ANATOMY AND PHYSIOLOGY:
Every cell in the human body needs energy in order to function. The body’s primary energy source is glucose, a simple sugar resulting from the digestion of foods containing carbohydrates (sugars and starches). Glucose from the digested food circulates in the blood as a ready energy source for any cells that need it. Insulin is a hormone or chemical produced by cells in the pancreas, an organ located behind the stomach. Insulin bonds to a receptor site on the outside of cell and acts like a key to open a doorway into the cell through which glucose can enter. Some of the glucose can be converted to concentrated energy sources like glycogen or fatty acids and saved for later use. When there is not enough insulin produced or when the doorway no longer recognizes the insulin key, glucose stays in the blood rather entering the cells.
Image Source: www.caninsulin.com/Pathophysiology-algorithm.htm
Several blood tests are used to measure blood glucose levels, the primary test for diagnosing diabetes. Additional tests can determine the type of diabetes and its severity.
- Random blood glucose test — for a random blood glucose test, blood can be drawn at any time throughout the day, regardless of when the person last ate. A random blood glucose level of 200 mg/dL (11.1 mmol/L) or higher in persons who have symptoms of high blood glucose (see “Symptoms” above) suggests a diagnosis of diabetes.
- Fasting blood glucose test — fasting blood glucose testing involves measuring blood glucose after not eating or drinking for 8 to 12 hours (usually overnight). A normal fasting blood glucose level is less than 100 mg/dL. A fasting blood glucose of 126 mg/dL (7.0 mmol/L) or higher indicates diabetes. The test is done by taking a small sample of blood from a vein or fingertip. It must be repeated on another day to confirm that it remains abnormally high (see “Criteria for diagnosis” below).
- Hemoglobin A1C test (A1C) — The A1C blood test measures the average blood glucose level during the past two to three months. It is used to monitor blood glucose control in people with known diabetes, but is not normally used to diagnose diabetes. Normal values for A1C are 4 to 6 percent (show figure 3). The test is done by taking a small sample of blood from a vein or fingertip.
- Oral glucose tolerance test — Oral glucose tolerance testing (OGTT) is the most sensitive test for diagnosing diabetes and pre-diabetes. However, the OGTT is not routinely recommended because it is inconvenient compared to a fasting blood glucose test.
The standard OGTT includes a fasting blood glucose test. The person then drinks a 75 gram liquid glucose solution (which tastes very sweet, and is usually cola or orange-flavored). Two hours later, a second blood glucose level is measured.
Oral glucose tolerance testing is routinely performed at 24 to 28 weeks of pregnancy to screen for gestational diabetes; this requires drinking a 50 gram glucose solution with a blood glucose level drawn one hour later. For women who have an abnormally elevated blood glucose level, a second OGTT is performed on another day after drinking a 100 gram glucose solution. The blood glucose level is measured before, and at one, two, and three hours after drinking the solution.
When diet, exercise and maintaining a healthy weight aren’t enough, you may need the help of medication. Medications used to treat diabetes include insulin. Everyone with type 1 diabetes and some people with type 2 diabetes must take insulin every day to replace what their pancreas is unable to produce. Unfortunately, insulin can’t be taken in pill form because enzymes in your stomach break it down so that it becomes ineffective. For that reason, many people inject themselves with insulin using a syringe or an insulin pen injector,a device that looks like a pen, except the cartridge is filled with insulin. Others may use an insulin pump, which provides a continuous supply of insulin, eliminating the need for daily shots.
The most widely used form of insulin is synthetic human insulin, which is chemically identical to human insulin but manufactured in a laboratory. Unfortunately, synthetic human insulin isn’t perfect. One of its chief failings is that it doesn’t mimic the way natural insulin is secreted. But newer types of insulin, known as insulin analogs, more closely resemble the way natural insulin acts in your body. Among these are lispro (Humalog), insulin aspart (NovoLog) and glargine (Lantus).
A number of drug options exist for treating type 2 diabetes, including:
· Sulfonylurea drugs. These medications stimulate your pancreas to produce and release more insulin. For them to be effective, your pancreas must produce some insulin on its own. Second-generation sulfonylureas such as glipizide (Glucotrol, Glucotrol XL), glyburide (DiaBeta, Glynase PresTab, Micronase) and glimepiride (Amaryl) are prescribed most often. The most common side effect of sulfonylureas is low blood sugar, especially during the first four months of therapy. You’re at much greater risk of low blood sugar if you have impaired liver or kidney function.
· Meglitinides. These medications, such as repaglinide (Prandin), have effects similar to sulfonylureas, but you’re not as likely to develop low blood sugar. Meglitinides work quickly, and the results fade rapidly.
· Biguanides. Metformin (Glucophage, Glucophage XR) is the only drug in this class available in the United States. It works by inhibiting the production and release of glucose from your liver, which means you need less insulin to transport blood sugar into your cells. One advantage of metformin is that is tends to cause less weight gain than do other diabetes medications. Possible side effects include a metallic taste in your mouth, loss of appetite, nausea or vomiting, abdominal bloating, or pain, gas and diarrhea. These effects usually decrease over time and are less likely to occur if you take the medication with food. A rare but serious side effect is lactic acidosis, which results when lactic acid builds up in your body. Symptoms include tiredness, weakness, muscle aches, dizziness and drowsiness. Lactic acidosis is especially likely to occur if you mix this medication with alcohol or have impaired kidney function.
· Alpha-glucosidase inhibitors. These drugs block the action of enzymes in your digestive tract that break down carbohydrates. That means sugar is absorbed into your bloodstream more slowly, which helps prevent the rapid rise in blood sugar that usually occurs right after a meal. Drugs in this class include acarbose (Precose) and miglitol (Glyset). Although safe and effective, alpha-glucosidase inhibitors can cause abdominal bloating, gas and diarrhea. If taken in high doses, they may also cause reversible liver damage.
· Thiazolidinediones. These drugs make your body tissues more sensitive to insulin and keep your liver from overproducing glucose. Side effects of thiazolidinediones, such as rosiglitazone (Avandia) and pioglitazone hydrochloride (Actos), include swelling, weight gain and fatigue. A far more serious potential side effect is liver damage. The thiazolidinedione troglitzeone (Rezulin) was taken off the market in March 2000 because it caused liver failure. If your doctor prescribes these drugs, it’s important to have your liver checked every two months during the first year of therapy. Contact your doctor immediately if you experience any of the signs and symptoms of liver damage, such as nausea and vomiting, abdominal pain, loss of appetite, dark urine, or yellowing of your skin and the whites of your eyes (jaundice). These may not always be related to diabetes medications, but your doctor will need to investigate all possible causes.
· Drug combinations. By combining drugs from different classes, you may be able to control your blood sugar in several different ways. Each class of oral medication can be combined with drugs from any other class. Most doctors prescribe two drugs in combination, although sometimes three drugs may be prescribed. Newer medications, such as Glucovance, which contains both glyburide and metformin, combine different oral drugs in a single tablet.
- Advice patient about the importance of an individualized meal plan in meeting weekly weight loss goals and assist with compliance.
- Assess patients for cognitive or sensory impairments, which may interfere with the ability to accurately administer insulin.
- Demonstrate and explain thoroughly the procedure for insulin self-injection. Help patient to achieve mastery of technique by taking step by step approach.
- Review dosage and time of injections in relation to meals, activity, and bedtime based on patients individualized insulin regimen.
- Instruct patient in the importance of accuracy of insulin preparation and meal timing to avoid hypoglycemia.
- Explain the importance of exercise in maintaining or reducing weight.
- Advise patient to assess blood glucose level before strenuous activity and to eat carbohydrate snack before exercising to avoid hypoglycemia.
- Assess feet and legs for skin temperature, sensation, soft tissues injuries, corns, calluses, dryness, hair distribution, pulses and deep tendon reflexes.
- Maintain skin integrity by protecting feet from breakdown.
- Advice patient who smokes to stop smoking or reduce if possible, to reduce vasoconstriction and enhance peripheral flow.
Daisy Jane Antipuesto RN MN
Currently a Nursing Local Board Examination Reviewer. Subjects handled are Pediatric, Obstetric and Psychiatric Nursing. Previous work experiences include: Clinical instructor/lecturer, clinical coordinator (Level II), caregiver instructor/lecturer, NC2 examination reviewer and staff/clinic nurse. Areas of specialization: Emergency room, Orthopedic Ward and Delivery Room. Also an IELTS passer.