Curing Diabetes

To diagnose peripheral vascular disease, the physician may use Doppler ultrasonography, plethysmography, or arteriography.Doppler ultrasonography, a noninvasive test, evaluates how fast blood flows through an artery and confirms arterial occlusion. This test uses a transducer to direct high-frequency sound waves toward the artery that’s being evaluated. When the sound waves strike red blood cells (RBes) moving through the artery, they’re reflected to the transducer. The frequency with which the sound waves are reflected indicates the speed and strength of the blood flow. The sound waves are amplified and then recorded.

To localize an occlusion, blood pressure readings are taken at the thigh, calf, and ankle of the affected leg during Doppler ultrasonography. If the systolic blood pressure at one of these sites is more than 20 mm Hg lower than the brachial systolic blood pressure, arterial occlusion probably exists at or near the site.

Plethysmography detects blood volume and pressure in a limb using a plethysmograph (a pulse volume recorder). It’s especially useful when blood vessels are calcified. During plethysmography, blood pressure is measured at the thigh, calf, and ankle. If the systolic blood pressure at one of these sites is more than 20 mm Hg lower than the brachial systolic blood pressure, arterial occlusion probably exists at or near the site. While blood pressure is measured, the plethysmograph displays the blood flow as sound waves on a strip, similar to an ECG tracing. Decreased amplitude in the sound waves indicates arterial occlusion

An ophthalmologist uses laser photocoagulation to seal microaneurysms so that they don’t hemorrhage; control the growth of new blood vessels, which may eventually rupture and hemorrhage; and destroy capillaries responsible for plasma and lipid leakage into the retina.Argon laser photocoagulation, the most common procedure for diabetic retinopathy, uses laser beams to destroy specific aneurysms and new and leaking blood vessels. Pan retinal photocoagulation, which controls widespread retinal changes, is used to treat patients who have already experienced some bleeding and vision loss and who have a high risk of more vision loss. In this procedure, the ophthalmologist scatters laser beams across the retina, producing as many as 2,000 burns. These burns reduce the retina’s demand for oxygen, which, in turn, reduces new blood vessel growth. In both procedures, the ophthalmologist avoids the macula to protect the patient’s visual acuity.

Complications of laser therapy depend on the type and number of treatments. Some patients experience discomfort. Others complain of a slight loss of vision, a decrease in peripheral vision, or impaired night vision.

Peripheral vascular disease is more common and occurs at a younger age in people with diabetes than in the general population. Among nondiabetic patients, far more men than women develop peripheral vascular disease. However, among those with diabetes, almost as many women as men develop it.Nondiabetic patients with peripheral vascular disease usually develop a single arterial occlusion in one leg and have normal collateral blood vessels. However, patients with diabetes usually develop several occlusions in both legs and have poor collateral circulation.

In patients who have diabetes and peripheral vascular disease, hyperglycemia, uncontrolled hypertension, or other factors can lead to atherosclerotic changes in the peripheral arteries. These changes may include capillary basement membrane thickening and increased platelet adhesion. They may lead to arterial occlusion, which diminishes the oxygen supply to the tissues, and subsequent muscle tissue ischemia and pain. Unfortunately, the diabetic patient’s poor tissue perfusion and impaired small vessels may reduce her ability to develop good collateral circulation to bypass the occlusion.

If your diabetic patient has hyperlipidemia, she’s at even greater risk for developing peripheral vascular disease. If she smokes, she’ll experience further compromised circulation. Smoking increases the progression of atherosclerosis by increasing LDL and triglyceride levels and decreasing HDL levels. It also raises the blood pressure, which can damage the arterial endothelium. The nicotine in cigarettes induces vasospasm and increases blood viscosity and clotting factor concentrations, which helps diminish arterial circulation.

If peripheral vascular disease is untreated, your patient may develop infections or even gangrene in her legs, which may lead to amputation. More than half of all nontraumatic amputations of the lower leg are caused by peripheral vascular disease in patients with diabetes.

In the United States, diabetes is the most common cause of end-stage renal disease, the final stage of nephropathy. Diabetic nephropathy occurs in Type 1 and Type 2 diabetes. About 35% of patients who’ve had Type 1 diabetes for more than 20 years develop end-stage renal disease. Among those with Type 2 diabetes, the risk of end-stage renal disease may be higher or lower, depending on the patient’s ethnic group. African-Americans, Native Americans, and Mexican-Americans are at higher risk than whites. Other risk factors for diabetic nephropathy include hypertension, poor blood glucose control, genetic predisposition, and high protein intake.Diabetic nephropathy develops over many years. Typically, diabetic nephropathy in patients with Type 1 diabetes progresses through five stages . However, patients with Type 2 diabetes may not progress through these five stages in the same manner as patients with Type 1 diabetes.

The exact cause of kidney destruction in diabetic nephropathy isn’t known. What’s known is that kidney damage occurs in the glomerulus, which consists of tufts of capillaries in the renal corpuscle, which is surrounded by Bowman’s capsule. The glomerular capillaries are made up of three layers of cells: the endothelium, basement membrane, and visceral epithelium. Mesangial cells lie between and support the capillaries.

Normally, blood enters the glomerulus through the afferent arteriole and exits by the efferent arteriole. As blood passes through the glomerulus, water, electrolytes, creatinine, urea nitrogen, and glucose filter across the capillary basement membrane into Bowman’s capsule. This filtrate is similar to blood plasma, but it doesn’t normally contain proteins. After the filtrate enters Bowman’s capsule, it flows through the tubules of the kidney and is eventually excreted from the body.

In diabetic nephropathy, kidney destruction results from gradual structural changes in the glomerulus. First, the glomerulus enlarges. Then glomerulosclerosis-the replacement of normal glomerular tissue with fibrous scar tissue occurs. In diffuse glomerulosclerosis, the more common type, the basement membrane of the glomerular capillaries thickens and eventually leaks capillary fluid. Also, the mesangial matrix (the spongy network surrounding the mesangial cells) thickens. In nodular glomerulosclerosis, hyaline nodules (hard masses of glassy, eosinophilic substances) form in the mesangial part of the glomerulus. In both types of glomerulosclerosis, the sclerotic changes disrupt the function of increasing numbers of glomeruli, slowly impairing the patient’s renal function.

Although diabetic nephropathy has no cure, certain interventions can slow its progress. These interventions include closely controlling blood glucose levels, using antihypertensive therapy, restricting protein intake, treating urinary tract infections (UTls), withholding nephrotoxic drugs and dyes, and using dialysis and transplantation.

Glucose Control

Tight blood glucose control-maintaining glucose levels as close to normal as possible without increasing the frequency or severity of hypoglycemic episodes-can help delay the onset and slow the progression of nephropathy. Tight blood glucose control also can reverse microalbuminuria in some patients. However, tight blood glucose control doesn’t affect the course of advanced nephropathy.

Antihypertensive Drug Therapy

Aggressive antihypertensive therapy may slow the progression of diabetic nephropathy. Certain antihypertensive drugs, such as angiotensin­converting enzyme (ACE) inhibitors and calcium channel blockers, may be used to treat hypertension. They also inhibit diabetic nephropathy in hypertensive patients and in normotensive patients with microalbuminuria.

However, ACE inhibitors may cause hyperkalemia and should be used cautiously if your patient has renal failure. Expect to avoid thiazide diuretics and beta-lockers because thiazide diuretics may worsen hyperlipidemia and hyperglycemia, and beta-blockers may mask or alter the symptoms of hypoglycemia.

Protein Restriction

Restricting your patient’s protein intake can reduce the rate of urine albumin excretion and kidney deterioration. The typical dietary protein intake in the United States is 1.2 to 1.4 g/kg/day. The physician may prescribe a diet that limits protein intake to 0.8 g/kg/day or less. For example, if your patient weighs 143 lb (65 kg), she may be limited to 52 grams of protein per day.

Therapy for Urinary Tract Infections

If your patient develops a UTI, her risk of renal dysfunction increases. If she has signs and symptoms of a UTI, such as dysuria (burning on urination), urinary frequency or urgency, or foul­smelling urine, the physician may request a urine sample for culture and sensitivity testing. And if your patient has an infection, the physician will prescribe an antibiotic. Before administering the antibiotic, however, check a current drug reference to determine if the drug is contraindicated or requires cautious use in a patient with a kidney disease, such as nephropathy.

Nephrotoxic Drug and Dye Restrictions

Your patient may be taking nephrotoxic drugs, such as an aminoglycoside or a nonsteroidal anti-inflammatory drug (NSAID). If so, the physician will monitor her kidney function by testing her serum creatinine levels. If your patient has impaired kidney function, the physician may adjust her drug dosage based on her GFR or creatinine clearance or prescribe a less nephrotoxic drug.

Radiographic dyes also are nephrotoxic. If your patient must undergo a test that requires radiographic dye, the physician may prescribe I.V. mannitol to be given 1 hour before the test to induce osmotic diuresis and minimize nephrotoxic effects.

Dialysis and Transplantation

A patient with end-stage renal disease may need hemodialysis or peritoneal dialysis, or she may be a candidate for a kidney transplant. Many patients who undergo hemodialysis develop sclerotic blood vessels from the numerous needle punctures at the dialysis access site. Eventually, they may have no more access sites to continue hemodialysis. These patients may be good candidates for peritoneal dialysis or kidney transplant.A donor kidney for a transplant can be obtained from a living relative, a living unrelated person, or a cadaver. A transplanted kidney has a 75% to 80% chance of functioning for at least 5 years. However, kidney transplants have many drawbacks:

• Donor kidneys are in short supply. Depending on your patient’s blood type and whether she has certain proteins or antibodies, she may never be offered a kidney.
• The risk of organ rejection is high, especially in the first year after the transplant.
• Expensive, long-term therapy with immunosuppressants is needed to help prevent organ rejection.
• Immunosuppression may lead to infection or malignancy .
• Immunosuppression makes tight glucose control more difficult.

Patients who test positive for the human immunodeficiency virus or who have a malignancy aren’t candidates for kidney transplant. Those with psychosis, active infection, severe neuropathies, or inoperable cardiovascular disease may not be approved for the procedure. Transplant complications include thrombosis, infection, anastomotic leaks (usually at the ureters), bleeding, and adverse effects of immunosuppression.