Diabetic Nephropathy – Symptoms and Causes

Diabetes mellitus, or diabetes, is a disease resulting in the body’s inability to regulate blood sugar levels. Diabetes is known to cause several long-term complications if it’s not treated correctly.

There are two main types of diabetes, type 1 and type 2. While having diabetes doesn’t guarantee that complications will arise, the risk of complications increases with the duration of having diabetes as well as how well it’s been controlled. 

One of the complications of diabetes is diabetic nephropathy, which is also called diabetic kidney disease.

Diabetic nephropathy is potentially life-threatening since the kidneys are crucial for filtering waste and toxins out of our blood. People with advanced kidney disease require dialysis when the kidneys are too damaged to function properly on their own.

Diabetic nephropathy is relatively common among people with diabetes. In fact, about 25% of people with diabetes will eventually develop kidney disease. Knowing the causes, risk factors, and ways to prevent diabetic nephropathy can help people with diabetes reduce their risk of developing kidney disease and live a healthier life.

What is diabetic nephropathy?

Diabetic nephropathy occurs when the tiny blood vessels in the kidneys become damaged due to chronic high blood sugar.

These blood vessels are called glomeruli and are responsible for filtering out toxins from our blood as well as extra fluid in the body. When the kidneys are damaged, their glomerular filtration rate (GFR) decreases, which means that they are filtering blood at a lower rate than is considered healthy.

A normal estimated glomerular filtration rate is 90 milliliters per minute. Diabetic nephropathy, or chronic kidney disease (CKD), occurs when this GFR is reduced below 90 and is divided into different stages of severity. According to the National Kidney Foundation, the stages of CKD are defined as:

Stage 1/GFR 90+. Early kidney damage with normal kidney function.

Stage 2/GFR 60-89. Kidney damage with mild loss of kidney function.

Stage 3a/GFR 45-59. Mild to moderate loss of kidney function.

Stage 3b/GFR 30-44. Moderate to a severe loss of kidney function.

Stage 4/GFR 15-29. Severe loss of kidney function.

Stage 5/GFR less than 15. Kidney failure. This is also called end-stage renal disease and requires dialysis. 

Symptoms of kidney disease

Because of the vital role kidneys play in the body, signs of kidney disease can show up in a variety of ways.

Kidney tests: Renal (kidney) tests may be altered when they are performed by a healthcare provider or laboratory. Common renal tests performed include the eGFR (as discussed above), as well as the ACR (albumin to creatinine ratio). The ACR is a urine test that measures the amount of protein called albumin in the urine, which is a sign of kidney damage. Protein in the urine is called proteinuria or microalbuminuria. Other blood tests, such as BUN and creatinine, can be elevated with kidney disease, as well as numerous other tests connected to kidney function.

Renal biopsy: A renal biopsy can be done to determine the pathophysiology of a patient’s kidney disease. *Interestingly, the preferred term for kidney disease in a diabetic patient is diabetic kidney disease, and the term diabetic nephropathy should technically only be used in those who have had a confirmed diagnosis via renal biopsy.* However, renal biopsies aren’t used with the majority of people with diabetic kidney disease.

According to the National Kidney Foundation, 10 signs that you may have kidney disease include:

1. Fatigue and trouble concentrating. A severe decrease in kidney function can lead to a buildup of toxins and impurities in the blood. This can cause people to feel tired, weak, and can make it hard to concentrate. Another complication of kidney disease is anemia, which can cause weakness and fatigue.
   
   
2. Trouble sleeping. When the kidneys aren’t filtering properly, toxins stay in the blood rather than leaving the body through the urine. This can make it difficult to sleep. There is also a link between obesity and chronic kidney disease, and sleep apnea is more common in those with chronic kidney disease compared with the general population.
   
   
3. Dry and itchy skin. Healthy kidneys do many important jobs. They remove wastes and extra fluid from your body, help make red blood cells, help keep bones strong, and work to maintain the right amount of minerals in your blood. Dry and itchy skin can be a sign of the mineral and bone disease that often accompanies advanced kidney disease when the kidneys are no longer able to keep the right balance of minerals and nutrients in your blood.
   
   
4. Increased urge to urinate. If you feel the need to urinate more often, especially at night, this can be a sign of kidney disease. When the kidney’s filters are damaged, it can cause an increase in the urge to urinate. Sometimes this can also be a sign of a urinary infection or enlarged prostate in men.
   
   
5. Blood in the urine. Healthy kidneys typically keep the blood cells in the body when filtering wastes from the blood to create urine, but when the kidney’s filters have been damaged, these blood cells can start to “leak” out into the urine. In addition to signaling kidney disease, blood in the urine can be indicative of tumors, kidney stones, or an infection.
   
   
6. Foamy urine. Excessive bubbles in the urine – especially those that require you to flush several times before they go away—indicate protein in the urine. This foam may look like the foam you see when scrambling eggs, as the common protein found in urine, albumin, is the same protein that is found in eggs.
   
   
7. Eye puffiness. Protein in the urine is an early sign that the kidneys’ filters have been damaged, allowing the protein to leak into the urine. This puffiness around your eyes can be due to the fact that your kidneys are leaking a large amount of protein in the urine, rather than keeping it in the body.
   
   
8. Swollen feet and ankles. Decreased kidney function can lead to sodium retention, causing swelling in your feet and ankles. Swelling in the lower extremities can also be a sign of heart disease, liver disease, and chronic leg vein problems.
   
   
9. Poor appetite. This is a very general symptom, but a buildup of toxins resulting from reduced kidney function can be one of the causes.
   
   
10. Muscle cramping. Electrolyte imbalances can result from impaired kidney function. For example, low calcium levels and poorly controlled phosphorus may contribute to muscle cramping.

What causes diabetic nephropathy?

When blood sugar levels are high, such as with diabetes, the kidneys filter out more blood than usual. Chronic high blood sugar is also known to damage the arteries and vessels of the body, which are essential for supplying blood to the hard-working organs.

Over time, this weakens the kidneys from over-work and damages the delicate blood vessels in the kidneys. When these blood vessels become weakened, the kidneys lose some of their efficiency and ability to filter blood properly.

The kidneys play a large role in fluid and blood pressure regulation. When the kidneys are damaged, it can cause an unhealthy change in blood pressure, which further damages the kidneys in a circular effect.

Risk factors for diabetic nephropathy

Some of the risk factors for diabetic nephropathy/diabetic kidney disease include:

• High blood sugar (hyperglycemia) that’s not well-controlled, especially in those with a long history of diabetes
  
  
• High blood pressure (hypertension) that’s not controlled
  
  
• Being a smoker
  
  
• High blood cholesterol
  
  
• A family history of diabetes and kidney disease

Complications

Some of the possible complications from diabetic nephropathy include:

• Fluid retention, which could lead to swelling in your arms and legs, high blood pressure, or fluid in your lungs (pulmonary edema)
  
  
• A rise in potassium levels in your blood (hyperkalemia)
  
  
• Heart and blood vessel disease (cardiovascular disease), possibly leading to stroke
  
  
• Damage to the blood vessels of the retina (diabetic retinopathy)
  
  
• Anemia
  
  
• Foot sores, erectile dysfunction, diarrhea and other problems related to damaged nerves and blood vessels
  
  
• Pregnancy complications that carry risks for the mother and the developing fetus
  
  
• Irreversible damage to your kidneys (end-stage kidney disease), eventually need either dialysis or a kidney transplant for survival

Is it possible to prevent diabetic nephropathy?

While diabetic nephropathy is always a possibility in those with diabetes, it can largely be prevented by reducing the risk factors. This is mainly accomplished by managing blood sugar and blood pressure levels well.

Ways to help prevent diabetic nephropathy include:

• Keep blood sugar levels well-managed/at target
  
  
• Manage high blood pressure and other medical conditions
  
  
• Take OTC medications as instructed; certain pain relievers can cause further kidney damage in those with kidney disease if taken improperly
  
  
• Maintain a healthy weight
  
  
• Don’t smoke

Reducing your HBA1C to reduce the risk of diabetic nephropathy

There are many steps you can take to reduce your hemoglobin A1c, which is a measure of blood sugar levels. Lower A1c is often correlated with a reduced risk of diabetes complications. Some ways to help lower the A1c include:

• Taking medications as prescribed, especially diabetes medications and blood pressure medications. Always speak with your healthcare provider before changing medication doses.
  
  
• Limit refined carbs & added sugar: Refined carbohydrates, such as white bread, enriched pasta, and foods with added sugar, tend to raise blood sugar levels in those with diabetes. Instead of choosing white flour/enriched grains, opt for whole grains/high-fiber foods to help promote more balanced blood sugars. 
  
  Foods like whole-wheat bread, oatmeal, and brown rice raise blood sugar more slowly than their enriched counterparts, which helps reduce both blood sugar spikes and insulin resistance. Limiting added sugar to less than 25 grams per day is also helpful in managing blood sugar levels.

• Eat a high-fiber diet. Foods rich in fiber tend to raise blood sugar levels more slowly than low-fiber foods. Fiber is in foods such as fruits, vegetables, grains, nuts, seeds, and legumes. Fiber is also beneficial for promoting heart health and can help reduce the risk of cardiovascular disease. A good amount of fiber to aim for is around 30 grams per day.
  
  
• Be more physically active. Being physically active is an important way to promote healthy blood sugar levels and reduce hemoglobin A1c. 150 minutes per week of moderate physical activity, such as brisk walking, is associated with an improvement in blood sugar levels. 
  
  
• Check blood sugar levels regularly. Having your hemoglobin A1c checked every 3-6 months as well as monitoring blood sugar levels at home is a great way to stay on top of your treatment plan and make changes as needed.

How is diabetic nephropathy treated?

Blood sugar management

Managing blood sugar levels is one of the primary goals in treating diabetic nephropathy. In general, a hemoglobin A1c of less than 7% is ideal for the reduction of diabetes complications such as kidney disease.

Blood pressure medications

In the earlier stages of nephropathy, blood pressure medications are often used as a treatment. Medications called angiotensin-converting enzyme (ACE) inhibitors, and angiotensin II receptor blockers (ARBs) are used to treat high blood pressure. Using both of these together isn’t advised because of increased side effects.

Cholesterol-lowering medications may also be used to treat diabetic nephropathy because they can help reduce protein in the urine. Statins are the most commonly prescribed cholesterol-lowering medications.

Dialysis

More advanced cases of diabetic nephropathy are often treated with dialysis. Dialysis is usually one of the last treatment options once kidney disease has progressed to the end-stage. There are two types of dialysis: hemodialysis and peritoneal dialysis. Hemodialysis is performed in a healthcare setting such as a dialysis center, while peritoneal dialysis can be performed by the patient at home. Dialysis can be performed daily or around three times per week, depending on the kind of dialysis and severity of kidney damage.

Kidney transplant

Another option is a kidney transplant, in which the patient receives one kidney from a donor. The donor will need to be matched with the recipient and go through several tests to ensure compatibility.

There are risks with a kidney transplant, and recipients of a donor’s kidney often need to take immunosuppressants, or anti-rejection medications to help make sure their body doesn’t reject their new kidney. This can increase the risk of illness and infections. However, most people receiving a donor’s kidney will gladly trade that risk for an improvement in the quality of life and not having to undergo dialysis and other treatments anymore.

Conclusion

The kidneys are vital organs responsible for removing waste products out of the blood as well as extra fluid out of the body. They play a large role in fluid regulation and blood pressure.

Diabetic nephropathy, or diabetic kidney disease, is a potential complication of both type 1 and type 2 diabetes. It occurs when the tiny vessels of the kidneys are damaged, therefore reducing their ability to filter blood, which can increase the amount of toxins and waste in the blood and cause protein to be leaked into the urine. Kidney disease is classified into 5 stages, with stage 5 being the most severe and considered “end-stage.” 

Diabetic nephropathy is treated with a good diabetes management plan, blood pressure regulation, dialysis, and even kidney transplants in some cases. It can be prevented through good management of blood sugars and blood pressure, which can be achieved through a combination of medications and healthy lifestyle habits.

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