Diabetic Nephropathy
Diabetic nephropathy (DN) is a significant complication associated with diabetes mellitus, primarily characterized by kidney damage that impairs the body's ability to remove waste. This condition leads to elevated levels of a protein called albumin in urine, often occurring without symptoms in its early stages. Patients may remain undiagnosed for years, heightening their risk of serious issues such as cardiac problems and kidney failure. Various factors, including type 1 diabetes, high blood pressure, family history, and certain ethnic backgrounds, can increase the likelihood of developing DN.
The kidneys, through intricate structures known as nephrons, filter blood and create urine. In diabetics, prolonged high blood sugar can damage these filtering units, especially the glomeruli, leading to scarring and reduced kidney function over time. Diagnosis typically involves routine screening for albumin levels, alongside blood tests and imaging, to assess kidney health. Treatment focuses on controlling blood sugar and blood pressure, possibly requiring medication adjustments, dietary changes, and in severe cases, dialysis or kidney transplantation. Understanding diabetic nephropathy is crucial for prevention and management, particularly among those at higher risk.
Diabetic Nephropathy
Diabetic nephropathy (DN) is a serious complication of the disease diabetes mellitus. It is caused by kidney damage that affects waste removal from the body. This damage results in higher levels of a protein called albumin in the urine. In the early stages, there are few symptoms, and the condition may be present for years before it becomes serious enough to be detected. Patients with this condition are at a higher risk for cardiac problems and kidney failure, both of which can be fatal.
Some conditions can make a diabetic more likely to develop DN, including type 1 diabetes diagnosed in childhood, high blood pressure, family history, smoking, and ethnic background. DN is the leading cause of end-stage renal disease (ESRD) in the United States. Approximately 40 percent of people who require dialysis because of ESRD are diabetics.
Causes
Diabetes is a disease in which the body's ability to produce the hormone insulin is impaired. Insulin helps regulate the amount of glucose, or sugar, in the blood and urine. Prolonged exposure to high levels of glucose in the blood can cause damage to the blood vessels, nerves, and kidneys.
Kidneys have about one million nephrons inside them. These small but complex units filter the blood to remove the end products of metabolism—or what is left after the body burns food for energy—and convert it into urine, which is excreted from the body. In diabetics, especially those who might not know they are diabetic and are therefore untreated, the excess glucose in the blood can cause damage to the nephrons, especially the glomeruli, the specific part of nephrons responsible for filtering the blood. Over time, the glomeruli can become scarred, which limits their ability to function. If the damage becomes severe, the kidneys can shut down and the patient will require dialysis. In this process, the blood is removed from the body by a tube, filtered by a special machine, and returned to the body via another tube.
Risk Factors
All diabetics are at risk for DN, including those who do not know they have diabetes. It is estimated that more than six million people in the United States alone may have type 2 diabetes without knowing it. These people are at greater risk for developing DN. Other risk factors include high blood pressure, a family history of kidney disease or diabetes with kidney disease, and smoking. In addition, certain ethnic groups have an increased risk of developing diabetes and DN, including African Americans, Native Americans, and Hispanic and Latino people.
Symptoms
In the early stages of diabetic nephropathy, there may be no symptoms. The disease comes on slowly, and damage to the kidneys can begin ten years before any symptoms present. When the damage becomes severe enough, the patient will likely experience fatigue, headaches, digestive issues, frequent nighttime urination, swelling or cramping in the lower extremities, and itchy skin.
Diagnosis
Because DN occurs so frequently in diabetics, comes on slowly, and may be present for years without any symptoms, physicians routinely screen patients for higher levels of albumin in the urine. This condition, known as albuminuria, indicates that there is kidney damage. DN is diagnosed when a patient has albuminuria with protein levels greater than 300 milligrams in a 24-hour urine collection accompanied by damage to the glomeruli and high blood pressure. Physicians use blood tests and urine tests as part of the diagnosis and may use ultrasound technology to image the kidneys. In some cases, a kidney biopsy may be ordered.
Patients newly diagnosed with type 2 diabetes are generally tested immediately for DN because their condition may have existed without detection for some time. In these patients, kidney disease may have begun even before they were aware of their diabetes.
Kidney disease caused by DN is categorized by five stages. These stages are based on the ability of the glomeruli to continue filtering the blood, known as the glomerular filtration rate, or GFR. Stage 1 indicates kidney damage with continued normal GFR. Stage 2 is kidney damage with mild decrease in GFR. Stage 3 indicates moderate decrease in GFR, while Stage 4 is a severe decrease in GFR. Stage 5 is kidney failure, necessitating medical intervention such as dialysis or a kidney transplant.
Treatments
The first step in treatment is to minimize the impact of diabetic nephropathy by ensuring blood sugar levels are under control. This may require medication changes or adjustments, exercise, and/or weight loss. Adequate diabetic control will minimize the amount of blood glucose and reduce the chances of it causing damage to other parts of the body, including the kidneys. Adequate blood pressure control is also important, so medication and other steps to reduce high blood pressure are part of the treatment for DN. Avoiding dietary sodium is often recommended, and some patients will be advised to reduce the intake of dietary protein as well.
In addition, patients are often advised to avoid medications known to adversely affect the kidneys, including non-steroidal anti-inflammatory drugs (NSAIDs) and higher doses of aspirin. Diuretics can also present a problem, as can the radiocontrast agents used in some imaging tests.
In severe cases, a patient will be placed on dialysis. Stage 5 patients may also require a kidney transplant, where the damaged kidney or kidneys are surgically removed and replaced by a donor kidney. Because a person can live with one kidney, a kidney donation may come from a living person, such as a relative or another individual who is medically compatible with the patient.
Bibliography
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