Kidney Diseases

Chronic Kidney Disease

Chronic kidney disease (CKD) is a progressive loss in kidney function over a period of months or years. Each of your kidneys has about a million tiny filters, called nephrons. If nephrons are damaged, they stop working. For a while, healthy nephrons can take on the extra work. But if the damage continues, more and more nephrons shut down. After a certain point, the nephrons that are left cannot filter your blood well enough to keep you healthy.

When kidney function falls below a certain point, it is called kidney failure. Kidney failure affects your whole body, and can make you feel very ill. Untreated kidney failure can be life-threatening.

Unfortunately, there are no signs of symptoms to warn you about early chronic kidney disease. It usually does not become better by itself, but it can be treated, especially if you get to know earlier. There are blood and urine tests that can be done to check for CKD. If unchecked however, kidney disease can progress to kidney failure.

CKD that goes undetected will lead to a progressive loss of kidney function that can lead to kidney failure (also called end-stage renal disease, ESRD) which means regular dialysis treatment or the worst case scenario, a kidney transplant.

CKD also opens you up to the risk of premature death from associated cardiovascular disease (i.e. heart attacks and strokes). If CKD is detected early and managed appropriately, the deterioration in kidney function can be slowed or even stopped, and the risk of associated cardiovascular complications can be reduced.

About 1 in 10 people have some degree of CKD. It can develop at any age but is more common with increasing age. After the age of 40, kidney filtration begins to fall by approximately 1% per year.  Besides the natural aging of the kidneys, many conditions which damage the kidneys are more common in older people including diabetes, high blood pressure and heart disease.

Indicators of Kidney Disease

The main indicator of kidney function is your blood level of creatinine, a waste product of the body produced by muscles and excreted by the kidneys. If kidney function is reduced, creatinine accumulates in the blood leading to an elevated level when a blood test is checked.

Kidney function is best measured by an indicator called GFR (Glomerular Filtration Rate) which measures the blood filtration rate by kidneys. This indicator allows doctors to determine if the kidney function is normal, and if not, to what level the reduced kidney function has deteriorated. In everyday practice, GFR can easily be estimated (eGFR), from measurement of the blood creatinine level, and taking into account, age, ethnicity and gender.

Stages of Chronic Kidney Disease (CKD)

Usually, kidney disease starts slowly and silently, and progresses over a number of years. Not everyone progresses from Stage 1 to Stage 5. Stage 5 is also known as End-Stage Renal Disease (ESRD).

Causes of CKD

High blood pressure (hypertension) and diabetes are the most common causes of kidney disease. The high blood pressure causes just over a quarter of all cases of kidney failure. Diabetes has been established as the cause of around one-third of all cases and is the commonest cause of ESRD in most developed countries.

Other less common conditions include inflammation (glomerulonephritis) or infections (pyelonephritis). Sometimes CKD is inherited (such as polycystic disease) or the result of longstanding blockage to the urinary system (such as enlarged prostate or kidney stones).

Some drugs can cause CKD, especially some pain-killing drugs (analgesics) if taken over a long time. Often doctors cannot determine what caused the problem.

Treating CKD

There is no cure for chronic kidney disease, although treatment can slow or halt the progression of the disease and can prevent other serious conditions developing.

The main treatments are a proper diet and medications, and for those who reach ESRD, long term dialysis treatment or kidney transplantation. In the early stages of kidney disease, a proper diet and medications may help to maintain the critical balances in the body that your kidneys would normally control. However, when you have kidney failure, wastes and fluids accumulate in your body and you need dialysis treatments to remove these wastes and excess fluid from your blood. Dialysis can be done either by machine (hemodialysis) or by using fluid in your abdomen (peritoneal dialysis). In suitable patients a kidney transplant combined with medications and a healthy diet can restore normal kidney function. Dialysis and kidney transplantation are known as renal replacement therapies (RRT) because they attempt to “replace” the normal functioning of the kidneys and are discussed in more detail below.

Kidney Transplantation

A kidney transplant is an operation to place a healthy (donor) kidney in your body to perform the functions your own diseased kidneys can no longer perform.

Kidney transplantation is considered the best treatment for many people with severe CKD because quality of life and survival are often better than in people who use dialysis. However, there is a shortage of organs available for donation. Many people who are candidates for kidney transplantation are put on a transplant waiting list and require dialysis until an organ is available.

A kidney can come from a living relative, a living unrelated person, or from a person who has died (deceased or cadaver donor); only one kidney is required to survive. In general, organs from living donors function better and for longer periods of time than those from donors who are deceased.

Overall, transplant success rates are very good. Transplants from deceased donors have an 85 to 90% success rate for the first year. That means that after one year, 85 to 90 out of every 100 transplanted kidneys are still functioning. Live donor transplants have a 90 to 95% success rate. Long-term success is good for people of all ages.

World Kidney Day 2012 was devoted to spreading the message about the importance of organ donation and kidney transplantation for people with ESRD.

Dialysis

Healthy kidneys clean blood and remove extra fluid in the form of urine. They also make substances that keep our body healthy. Dialysis replaces the blood cleaning functions when kidneys no longer work.

There are two types of dialysis: Hemodialysis and Peritoneal dialysis.

In hemodialysis, your blood is pumped through a dialysis machine to remove waste products and excess fluids. You are connected to the dialysis machine through a needle in a vein that is surgically enlarged (vascular access) or through a temporary plastic catheter placed in a vein. This allows blood to be removed from the body, circulate through the dialysis machine for cleansing, and then return to the body. Hemodialysis can be done at a dialysis center or at home. When done in a center, it is generally done three times a week and takes between three and five hours per session. Home dialysis is generally done three to seven times per week and takes between three and ten hours per session (often while sleeping).

Peritoneal dialysis is another form of dialysis used to remove waste products and excess water. It works on the same principle as hemodialysis, but your blood is cleaned while still inside your body rather than in a machine by adding clean fluid to your abdomen, letting it accumulate waste products from the blood and then draining it out. It is typically done at home. Some patients can perform peritoneal dialysis continuously while going about normal daily activities (continuous ambulatory peritoneal dialysis, CAPD)

Prevalence of CKD

About 1 in 10 people have some degree of CKD. It can develop at any age and various conditions can lead to CKD.

Kidney disease can affect people of all ages and races. African Americans, Hispanics, American Indians and people of South Asian origin (those from India, Bangladesh, Sri Lanka or Pakistan) have a higher risk of CKD. This risk is due in part to high rates of diabetes and high blood pressure in these communities.

CKD can occur at any age, but becomes more common with increasing age and is more common in women. Although about half of people aged 75 or more have some degree of CKD, many of these people do not actually have diseases of their kidneys; they have normal ageing of their kidneys. Simple blood and urine tests can detect CKD, and simple, low cost treatments can slow the progression of the disease, reduce the risk of associated heart attacks and strokes and improve quality of life.

Cost of CKD

The prevalence of kidney disease is increasing dramatically and the cost of treating this growing epidemic represents an enormous burden on healthcare systems worldwide. Even in high income countries, the very high cost of long term dialysis for increasing numbers of people is a problem.  In low and middle income countries long term dialysis is unaffordable. The best hope for reducing the human and economic costs of chronic kidney disease and end-stage renal disease therefore lies in prevention, for the following reasons.

  • Chronic kidney diseases are not curable and can cause people to need care for the rest of their lives.
  • If CKD is not detected early enough, the patient may progress to kidney failure which requires Renal Replacement Therapy (dialysis or transplantation) that is extremely costly and weighs heavily on healthcare budgets.
  • Chronic Kidney Diseases trigger other healthcare issues like cardiovascular diseases (heart attack and stroke), which will lead to premature death or disability and multiply the amount of amount of money needed for the healthcare of a patient.
  • In developed countries, ESRD is a major cost driver for patients, their families and the taxpayer.

In middle-income countries, access to life-saving therapies has progressively increased over the same period yet renal replacement therapy remains unaffordable for the majority of patients.

Developing countries, with a combined population of over 600 million people, cannot afford renal replacement at all – resulting in the death of over 1 million people annually from untreated kidney failure. Indeed, more than 80% of individuals receiving renal replacement therapy (RRT) live in the developed world because in developing countries it is largely unaffordable. In countries such as India and Pakistan, less than 10% of all patients who need it receive any kind of renal replacement therapy. In many African countries there is little or no access to RRT, meaning many people simply die. RRT is also used to treat acute kidney injuries where recovery of kidney function usually occurs if the patient can be kept alive by dialysis until that happens.  The lack of available RRT results in the preventable deaths of many thousands of children with diarrheal diseases and women with complications of pregnancy in the developing world every year.

Polycystic Kidney Disease (PKD)

Polycystic kidney disease (PKD) is an inherited kidney disorder that enlarges the kidneys and interferes with kidney function due to multiple cysts on the kidneys.

In early stages of the disease, the cysts enlarge the kidney and interfere with kidney function, resulting in chronic high blood pressure and kidney infections. The cysts may cause the kidneys to increase production of erythropoietin (the hormone that stimulates production of red blood cells) resulting in too many red blood cells, rather than the expected anaemia of chronic kidney disease.

The disease progresses slowly, ultimately causing end-stage kidney disease in which dialysis and transplantation are the only forms of treatment.

PKD comes in two forms. Autosomal Dominant Polycystic Kidney Disease (ADPKD) is the most common, affecting 1-in-400 to 1-in-500 adults. Autosomal Recessive Polycystic Kidney Disease (ARPKD) is far less common, affecting 1-in-10,000 at a far younger age, including new-borns, infants and children.

Diabetes

Kidney disease is becoming a growing problem in developing countries such as ours, caused by an explosion in cases of diabetes and high blood pressure, experts say.

People in rapidly urbanizing countries are adopting the unhealthy lifestyles that promote diabetes and high blood pressure, the leading causes of kidney disease. Left untreated, chronic kidney disease can result in potentially fatal conditions such as high blood pressure and heart disease, and can ultimately lead to kidney failure.

Diabetes is a life-long disease in which the body does not produce or properly use insulin, a hormone produced by the pancreas that is needed to convert sugar, starches and other food into energy needed for daily life.

The World Health Organization estimates that more than 180 million people worldwide have diabetes, and 10 to 20 percent of those will die of kidney failure. It predicts that the number of diabetics will double by 2030.

Type 1 Diabetes

Type-1 diabetes, usually diagnosed in children and young adults, is an autoimmune disease in which the body does not produce insulin. Therefore, a person who has type-1 diabetes must take insulin daily to live.

Symptoms of type 1 diabetes usually develop over a short period. Symptoms include increased thirst and urination, constant hunger, weight loss, blurred vision and extreme fatigue. If not diagnosed and treated with insulin, a person with type 1 diabetes can lapse into a life-threatening diabetic coma, also known as diabetic ketoacidosis.

Type 2 Diabetes

Typically occurring in adulthood, type-2 diabetes is the most common form. About 90 to 95 percent of people with diabetes have type-2. This form of diabetes is associated with older age, obesity, family history of diabetes, previous history of gestational diabetes, physical inactivity, and ethnicity.

When type-2 diabetes is diagnosed, the pancreas is usually producing enough insulin, but for unknown reasons, the body cannot use the insulin effectively, a condition called insulin resistance. After several years, insulin production decreases. The result is the same as for type 1 diabetes – glucose builds up in the blood and the body cannot make efficient use of its main source of fuel.

Unlike type-1 diabetes, the symptoms of type 2 diabetes develop gradually. Symptoms may include fatigue or nausea, frequent urination, unusual thirst, weight loss, blurred vision, frequent infections and slow healing of wounds or sores. Some patients may not exhibit any symptoms.

Gestational Diabetes

Gestational diabetes develops only during pregnancy. Like type-2 diabetes, it occurs more often in African Americans, American Indians, Hispanic Americans, and among women with a family history of diabetes. Women who have had gestational diabetes have a 20 to 50 percent chance of developing type-2 diabetes within 5 to 10 years.

What are the treatment options for advanced kidney failure?

Unfortunately for thousands of patients, kidney failure is often detected after significant damage is done. At this point renal replacement therapy (RRT — meaning dialysis or transplantation) is the only option, but according to World Kidney Day, 80 percent of people receiving RRT live in the developed world as it’s unaffordable in developing countries.

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Kidney transplants

Sometimes, the kidney may lose its ability to function properly. In extreme cases, they may cease to work. Such a condition is called kidney failure. When a patient loses 90 to 95 percent of his or her kidney function, they are considered to have End Stage Renal Disease (ESRD). At this point, life-saving treatment becomes necessary. Treatment options for patients with ESRD are dialysis (where an artificial kidney machine removes waste from the blood) or a kidney transplant from a living or deceased donor.

Occasionally, a patient with 85 percent loss of kidney function will undergo a transplant which allows them to avoid having to go on dialysis. Kidney patients and their families will discuss the best course of treatment with their doctors.

Related links:
Recipient preparation and evaluation
Pre-transplant recipient (patient) evaluation
Transplant surgery
Post-transplant care

Refrences
www.unos.org
www.clevelandclinic.org
https://www.kidneyresearchuk.org
http://edition.cnn.com/2009/HEALTH/11/13/kidney.disease.diabetes/
http://www.worldkidneyday.org/faqs/about-kidneys-and-kidney-disease/kidneys-and-chronic-kidney-disease/

Fortis Memorial Research Institute
Dr. PN Gupta, Paras Hospital