Kidney Disease in Diabetics

A singularly common problem associated with diabetes and the failure to keep it under control is kidney disease. This health problem is more common among patients who also have high blood pressure.

Putting the Kidney into Perspective

Nearly everyone has two kidneys, although only one is necessary.  Even then part of the organ is sufficient if the other portion is injured. Each kidney is connected to these 3 major components:[1]

  • The ureter, a narrow tube leading to the upper back wall of the bladder,
  • A muscular sac
  • The urethra which runs from the bladder to the external surface of the body

Physiology of the Kidneys

The kidney acts similarly to the municipal sewerage works. Like the removal of impurities from the water and sewage, the kidney purifies the blood of unwanted waste material and water. It then discharges what it filters as urine. The blood enters and leaves at the rate of a couple of pints a minute.[2]

The kidneys contain small units called nephrons and inside each nephron there is a glomerulus. Fluid from the blood leaks into the wall of the capillary in the glomerulus, a twisted capillary knot located in a drainage chamber – Bowman’s capsule. There are approximately between 1 million nephrons per kidney for filtering. Within the capsules, the blood enters the loop of Henle, which performs a highly specialized function. Non-waste, glucose for example, is reabsorbed to stay in the bloodstream while waste is directed to the urinary system. This occurs, however, only when your kidney is in good health.

Factors in the Development of Kidney Disease

There are several factors you may need to consider when it comes to kidney health. They consist of, but are not restricted to, the following[3]:

  • Genetic factors – Does anyone in your family have or had kidney disease?
  • Smoking
  • High blood pressure
  • Poor and insufficient blood glucose control
  • Insufficient controls of blood lipids

Pathology – When the Kidney Becomes Diseased

The term for kidney diseases associated with diabetes is Diabetic Nephropathy. The most common cause of chronic kidney damage or failure is diabetes. Statistics indicate that between one third and one half of all the patients who have T1D and twenty to thirty percent of those with T2D will develop kidney disease.

An onset of this health issue has serious consequences. It may result in the need to replace its function with an artificial kidney mechanism – dialysis. It may also lead to a kidney transplant. If either treatment fails, the patient will die.

Nephropathy and associated kidney failure is the most common cause of death for diabetics. It is also, because of the ability of dialysis to keep patients alive, one of the most expensive. This cost, in terms of money and the negative impact on the quality of life, can be reduced if the individual maintains control of their glucose levels. While debate rages about whether retaining glucose control will always reduce the instances of kidney disease, there is no doubt that nephropathy is likely to follow imperfect control of hyperglycemia.

Like many diabetic complications of the tissue, the fundamental problem may be found in the blood vessels. The changes are initially perceived in the knotted glomerulus, the basement membrane – the layer that supports the active cells. The membrane congeals and nodules take shape inside the glomerulus. In the early stages, filtration increases and the kidney becomes mildly distended. It works overtime to clear the glucose.

The next stage of the process involves the alteration of the correct filtration of the blood.  The blood vessels begin to leak, releasing an increased amount of protein molecules. This is reported by the lab as microalbuminuria – indicating a small amount is present.

Progression of the changes is slow. It is also hard to identify without deliberate screening for the problem.  Although the disease is progressing, it does not declare itself through overt symptoms. As a result, for many, the first indication of a serious problem of the kidneys is renal failure. This is why annual screening is so important.

Clinical Presentation

The most insidious aspect of kidney disease is its lack of symptoms until the disease has advanced. The capability of the kidneys to provide services in more depth than we require serves to mask the problem until it is too late. By the time it is noted, the clinical condition of nephrosis has appeared. The following indications are present:

  • Increase in weight due to water retention – particularly visible in the face, hands and feet but invisible in the chest and abdomen
  • Bruises – the patient is easily bruised
  • Protein is now in some quantity in the urine. Blood tests reveal raised levels of markers such as creatinine and blood urea nitrogen (BUN)
  • Uremic coma as the disease progresses. It may be reversed by dialysis or kidney transplant

A tissue diagnosis from a biopsy can confirm a diagnosis of nephropathy.

Treatment

Prevention is always the best treatment. Early diagnosis and continuous control of the blood glucose level will help prevent the health problem arising. There is also a need to keep blood pressure and cholesterol under control. Controls for the former involves the taking of medications called angiotensin converting enzyme (ACE) inhibitors, such as lisinopril. Diligence must also be maintained against any instance of urinary tract infection. You should be aware of any signs and inform your doctor of your suspicions.

Medications that need to be avoided include the groups known as non-steroidal anti-inflammatories (NSAIDs), such as motrin, ibuprofen, and alieve. You also need to look at making changes in your life style. If you smoke – give it up. If you are overweight then you should lose weight. You can also cut back on the amount of alcohol you drink and the amount of salt you ingest.[5]

References

[1] Guyton, AC; and Hall, JE (2011). Textbook of Medical Physiology, 12th ed. Philadelphia: Saunders.

[2] Burant, C.F. ed. (2008) Medical Management of Type 2 Diabetes 6th ed. Alexandria, VA: ADA.

[3] Meltzer, SJ; and Belton, AB (2009). Diabetes in Adults. Toronto: Key Porter Books.

[4] Tesch, GH (2010). “Macrophages and Diabetic Nephropathy.” Seminars in Nephrology, 30(3): 290-301.

[5] American Diabetes Association (2009). Type 2 Diabetes. Your Healthy Living Guide. Alexandria, VA: ADA.

This article was originally published July 12, 2012 and last revision and update of it was 9/10/2015.