Definition and Overview

Diabetic renal disease, also known as diabetic nephropathy, refers to irreversible kidney damage caused by high blood glucose (sugar) levels. It develops in approximately 35% of diabetic patients and is one of the deadly complications of diabetes as it can lead to kidney failure. Based on studies, the condition accounts for more than 50% of all cases of end-stage renal disease in the United States.

Those who are considered at most risk are obese people who are struggling to keep their diabetes and blood pressure under control. The condition occurs when tiny blood vessels inside the kidneys suffer from repeated damage and begin to lose their ability to filter waste and excess fluid from the blood. If the kidneys stop working completely, wastes and extra fluid will build up in the bloodstream, resulting in swelling and inadequate supply of clean blood for the body. This creates the need for dialysis, a treatment that takes over kidney function. It involves using a machine that filters and purifies the blood. Over time, patients on dialysis may require kidney transplantation wherein their kidneys are removed and replaced with healthy kidneys from a donor.

There are ways to prevent diabetic renal disease from developing or progressing. Patients with diabetes who work closely with their endocrinologist in reaching and maintaining their target blood glucose levels with medications and a healthy lifestyle can significantly reduce their risk of suffering from this complication.

Causes of Condition

People with uncontrolled diabetes and high blood pressure are at a significant risk of developing diabetic renal disease. When combined, these two conditions can cause damage to the delicate filtering system of the kidneys. Over time, this damage can worsen and lead to the scarring and thickening of blood vessels, preventing them from filtering the blood efficiently and causing them to leak protein into the urine. This damage can occur years before any symptoms begin, usually when the kidneys start to fail.

Aside from high blood pressure, other factors that can increase the risk of developing renal disease are:

  • Uncontrolled blood sugar levels

  • A high salt diet

  • Obesity or being overweight

  • Sedentary lifestyle

  • Type 1 diabetes that began before the patient is 20 years old

  • A family history of kidney disease and diabetes

  • Smoking

  • Race - Studies show the condition is more common in African Americans, Native Americans, and Hispanics than other races.

  • Heart disease

Key Symptoms

Diabetic renal disease does not produce any noticeable symptoms in the early stages. The only way for patients to know they have the condition is to have their kidneys regularly checked. When kidneys lose their ability to filter wastes and excess fluid from the blood, the following symptoms manifest:

  • Confusion

  • Fatigue

  • Frequent infections

  • General ill feeling

  • Increased need to urinate

  • Low blood sugar levels, which can occur if the kidneys are unable to remove excess insulin from the blood

  • Persistent itching

  • Poor appetite

  • Protein in the urine

  • Swelling of eyes, hands, ankles, and feet

  • Trouble sleeping

  • Weight loss

If the condition progresses to end-stage kidney failure, the patient will experience the following:

  • Abnormal heart rhythms

  • Muscle cramps

  • Abdominal pain

  • Diarrhoea

  • Fever

  • Nosebleeds

  • Rashes

Who to See and Types of Treatments Available

Diabetic renal disease can be diagnosed through:

  • Blood and urine tests - These are routine tests used to closely monitor the condition and kidney function of people with diabetes. A urine test can detect the presence of protein in the urine, which is the earliest sign of diabetic renal disease. Blood tests, on the other hand, indicate the patient’s average sugar levels for the past three months. Blood and urine tests are usually the first step in assessing any damage to the kidneys. If their results suggest an abnormality, additional diagnostic and imaging tests are performed.

  • Imaging tests - Magnetic resonance imaging (MRI), computed tomography (CT) scanning, x-rays, and renal ultrasound provide detailed images of the kidneys and surrounding structures. This helps doctors easily spot any abnormalities, such as changes in the kidney size and the presence of abnormal growths.

  • Renal biopsy - Involves extracting a small amount of kidney tissue for laboratory analysis. It can be performed percutaneously or through open surgery. A percutaneous renal biopsy is performed by inserting a renal needle through an incision and then into the kidney. In an open biopsy, the doctor makes an incision to surgically remove a sample tissue from the kidney while the patient is under the effects of general anaesthesia.

Treatment of diabetic renal disease focuses on preventing the condition from progressing and further damage to the kidneys. Patients are treated by an endocrinologist, a doctor specialising in the treatment of diabetes, and a nephrologist, a doctor specialising in the diagnosis and treatment of disorders affecting the kidneys. Treatment begins by keeping diabetes and high blood pressure under control. This can be achieved by combining the use of medications and making lifestyle changes.

Medications that are often prescribed for the treatment of diabetic renal disease include:

  • Angiotensin-converting enzyme (ACE) inhibitors

  • Statins or cholesterol-lowering drugs

  • Proper dosages of insulin

Living a healthy lifestyle also plays a crucial role in the treatment of the condition. To achieve the best possible outcomes, patients must:

  • Eat a well-balanced diet that is high in fruits and vegetables

  • Exercise on a regular basis – Doctors suggest at least one hour of exercise five to seven days a week

  • Stop smoking and avoid alcoholic beverages as much as possible

  • Drink at least 8 glasses of water every day as this helps the body effectively flush out toxins

If the condition has progressed to end-stage kidney disease, the only treatment options for patients are kidney dialysis and renal transplant.

References:

  • American Diabetes Association (2015). Standards of medical care in diabetes-2015. Diabetes Care, 38(Suppl 1): S1-S93.

  • Brownlee M, et al. (2011). Complications of diabetes mellitus. In S Melmed et al., eds., Williams Textbook of Endocrinology, 12th ed., pp. 1462-1551. Philadelphia: Saunders.

  • Yip JW, Jones SL, Wiseman MJ, Hill C, Viberti G. Glomerular hyperfiltration in the prediction of nephropathy in IDDM: a 10-year follow-up study. Diabetes. 1996 Dec. 45(12):1729-33.

  • Bherwani S, Saumya AS, Ahirwar AK, et al. The association of folic acid deficiency and diabetic nephropathy in patients with type 2 diabetes mellitus. Endocr Metab Immune Disord Drug Targets. 2016 Apr 15.

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