Why do kidney fail and how do Dialysis help patient recover…

What do the kidneys do?

The kidneys are bean-shaped organs, each about the size of a fist. They are located near the middle of the back, just below the rib cage, one on each side of the spine. The kidneys are sophisticated reprocessing machines. Every day, a person’s kidneys process about 200 quarts of blood to sift out about 2 quarts of waste products and extra water. The wastes and extra water become urine, which flows to the bladder through tubes called ureters. The bladder stores urine until releasing it through urination.

The kidneys remove wastes and water from the blood to form urine. Urine flows from the kidneys to the bladder through the ureters.

Wastes in the blood come from the normal breakdown of active tissues, such as muscles, and from food. The body uses food for energy and self-repairs. After the body has taken what it needs from food, wastes are sent to the blood. If the kidneys did not remove them, these wastes would build up in the blood and damage the body.

The actual removal of wastes occurs in tiny units inside the kidneys called nephrons. Each kidney has about a million nephrons. In the nephron, a glomerulus—which is a tiny blood vessel, or capillary—intertwines with a tiny urine-collecting tube called a tubule. The glomerulus acts as a filtering unit, or sieve, and keeps normal proteins and cells in the bloodstream, allowing extra fluid and wastes to pass through. A complicated chemical exchange takes place, as waste materials and water leave the blood and enter the urinary system.

In the nephron (left), tiny blood vessels intertwine with urine-collecting tubes. Each kidney contains about 1 million nephrons.

At first, the tubules receive a combination of waste materials and chemicals the body can still use. The kidneys measure out chemicals like sodium, phosphorus, and potassium and release them back to the blood to return to the body. In this way, the kidneys regulate the body’s level of these substances. The right balance is necessary for life.

In addition to removing wastes, the kidneys release three important hormones:

• erythropoietin, or EPO, which stimulates the bone marrow to make red blood cells
• renin, which regulates blood pressure
• calcitriol, the active form of vitamin D, which helps maintain calcium for bones and for normal chemical balance in the body

Dialysis is a medical process through which a person’s blood is cleansed of the toxins the kidneys normally would flush out. It is generally used when a person’s kidneys no longer function properly. This can be a result of congenital kidney disease, long-term diabetes, high blood pressure or other conditions.

Why do kidneys fail?

Most kidney diseases attack the nephrons, causing them to lose their filtering capacity. Damage to the nephrons can happen quickly, often as the result of injury or poisoning. But most kidney diseases destroy the nephrons slowly and silently. Only after years or even decades will the damage become apparent. Most kidney diseases attack both kidneys simultaneously.

The two most common causes of kidney disease are diabetes and high blood pressure. People with a family history of any kind of kidney problem are also at risk for kidney disease.

Diabetic Kidney Disease

Diabetes is a disease that keeps the body from using glucose, a form of sugar, as it should. If glucose stays in the blood instead of breaking down, it can act like a poison. Damage to the nephrons from unused glucose in the blood is called diabetic kidney disease. Keeping blood glucose levels down can delay or prevent diabetic kidney disease. Use of medications called angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) to treat high blood pressure can also slow or delay the progression of diabetic kidney disease.

High Blood Pressure

High blood pressure can damage the small blood vessels in the kidneys. The damaged vessels cannot filter wastes from the blood as they are supposed to.

A doctor may prescribe blood pressure medication. ACE inhibitors and ARBs have been found to protect the kidneys even more than other medicines that lower blood pressure to similar levels. The National Heart, Lung, and Blood Institute (NHLBI), one of the National Institutes of Health, recommends that people with diabetes or reduced kidney function keep their blood pressure below 130/80.

Glomerular Diseases

Several types of kidney disease are grouped together under this category, including autoimmune diseases, infection-related diseases, and sclerotic diseases. As the name indicates, glomerular diseases attack the tiny blood vessels, or glomeruli, within the kidney. The most common primary glomerular diseases include membranous nephropathy, IgA nephropathy, and focal segmental glomerulosclerosis. The first sign of a glomerular disease is often proteinuria, which is too much protein in the urine. Another common sign is hematuria, which is blood in the urine. Some people may have both proteinuria and hematuria. Glomerular diseases can slowly destroy kidney function. Blood pressure control is important with any kidney disease. Glomerular diseases are usually diagnosed with a biopsy—a procedure that involves taking a piece of kidney tissue for examination with a microscope. Treatments for glomerular diseases may include immunosuppressive drugs or steroids to reduce inflammation and proteinuria, depending on the specific disease.

Inherited and Congenital Kidney Diseases

Some kidney diseases result from hereditary factors. Polycystic kidney disease (PKD), for example, is a genetic disorder in which many cysts grow in the kidneys. PKD cysts can slowly replace much of the mass of the kidneys, reducing kidney function and leading to kidney failure.

Some kidney problems may show up when a child is still developing in the womb. Examples include autosomal recessive PKD, a rare form of PKD, and other developmental problems that interfere with the normal formation of the nephrons. The signs of kidney disease in children vary. A child may grow unusually slowly, vomit often, or have back or side pain. Some kidney diseases may be silent—causing no signs or symptoms—for months or even years.

If a child has a kidney disease, the child’s doctor should find it during a regular checkup. The first sign of a kidney problem may be high blood pressure; a low number of red blood cells, called anemia; proteinuria; or hematuria. If the doctor finds any of these problems, further tests may be necessary, including additional blood and urine tests or radiology studies. In some cases, the doctor may need to perform a biopsy.

Some hereditary kidney diseases may not be detected until adulthood. The most common form of PKD was once called “adult PKD” because the symptoms of high blood pressure and renal failure usually do not occur until patients are in their twenties or thirties. But with advances in diagnostic imaging technology, doctors have found cysts in children and adolescents before any symptoms appear.

Other Causes of Kidney Disease

Poisons and trauma, such as a direct and forceful blow to the kidneys, can lead to kidney disease.

Some over-the-counter medicines can be poisonous to the kidneys if taken regularly over a long period of time. Anyone who takes painkillers regularly should check with a doctor to make sure the kidneys are not at risk.

What happens if the kidneys fail completely?

Total or nearly total and permanent kidney failure is called ESRD. If a person’s kidneys stop working completely, the body fills with extra water and waste products. This condition is called uremia. Hands or feet may swell. A person will feel tired and weak because the body needs clean blood to function properly.

Untreated uremia may lead to seizures or coma and will ultimately result in death. A person whose kidneys stop working completely will need to undergo dialysis or kidney transplantation.

Dialysis

The two major forms of dialysis are hemodialysis and peritoneal dialysis. Hemodialysis uses a special filter called a dialyzer that functions as an artificial kidney to clean a person’s blood. The dialyzer is a canister connected to the hemodialysis machine. During treatment, the blood travels through tubes into the dialyzer, which filters out wastes, extra salt, and extra water. Then the cleaned blood flows through another set of tubes back into the body. The hemodialysis machine monitors blood flow and removes wastes from the dialyzer. Hemodialysis is usually performed at a dialysis center three times per week for 3 to 4 hours. A small but growing number of clinics offer home hemodialysis in addition to standard in-clinic treatments. The patient first learns to do treatments at the clinic, working with a dialysis nurse. Daily home hemodialysis is done 5 to 7 days per week for 2 to 3 hours at a time. Nocturnal dialysis can be performed for 8 hours at night while a person sleeps. Research as to which is the best method for dialysis is under way, but preliminary data indicate that daily dialysis schedules such as short daily dialysis or nocturnal dialysis may be the best form of dialysis therapy.

Hemodialysis.

In peritoneal dialysis, a fluid called dialysis solution is put into the abdomen. This fluid captures the waste products from a person’s blood. After a few hours when the fluid is nearly saturated with wastes, the fluid is drained through a catheter. Then, a fresh bag of fluid is dripped into the abdomen to continue the cleansing process. Patients can perform peritoneal dialysis themselves. Patients using continuous ambulatory peritoneal dialysis (CAPD) change fluid four times a day. Another form of peritoneal dialysis, called continuous cycling peritoneal dialysis (CCPD), can be performed at night with a machine that drains and refills the abdomen automatically.

Peritoneal dialysis.

Transplantation

A donated kidney may come from an anonymous donor who has recently died or from a living person, usually a relative. The kidney must be a good match for the patient’s body. The more the new kidney is like the person receiving the kidney, the less likely the immune system is to reject it. The immune system protects a person from disease by attacking anything that is not recognized as a normal part of the body. So the immune system will attack a kidney that appears too “foreign.” The patient will take special drugs to help trick the immune system so it does not reject the transplanted kidney. Unless they are causing infection or high blood pressure, the diseased kidneys are left in place. Kidneys from living, related donors appear to be the best match for success, but kidneys from unrelated people also have a long survival rate. Patients approaching kidney failure should ask their doctor early about starting the process to receive a kidney transplant.

Kidney transplantation.

Dialysis

Dialysis can be used in the treatment of patients suffering from poisoning or overdose, in order to quickly remove drugs from the bloodstream.

Here is a illustration on how Dialysis works.

Dialysis may be either temporary or permanent, depending on the person. If a dialysis patient is waiting on a kidney transplant, the procedure may be temporary. However, if the patient is not a good transplant candidate, or a transplant would not alleviate the condition, dialysis may be a life-long routine.

There are two main kinds of dialysis used: peritoneal and hemodialysis. Peritoneal dialysis can be done in the home, by the patient, either alone or with a helper. Peritoneal dialysis uses the body’s peritoneal membrane, inside the abdomen, to infuse a glucose-based solution into the abdominal cavity. The solution remains in the abdomen for about two hours, and is then drained out.

A surgeon must place a tube with a titanium plug inside the patient’s abdomen for this procedure. The patient must also be trained to perform the procedure. Absolute attention to sterile procedures is required, orperitonitis could result. This is especially dangerous in patients whose immune systems may already be compromised or suppressed.

Hemodialysis is probably the procedure that most people are familiar with. This procedure is performed at a hospital or dialysis center. The patient is hooked up, via a tube in the veins, to a machine that circulates his blood through a machine, through semi-permeable filters that take out the toxins in the blood. The procedure usually takes three to four hours.

While dialysis may be a life-saving procedure, it is not perfect. Patients must follow a specialized diet that is higher in protein and lower in phosphorus and potassium, since these minerals tend to build up quickly in the blood. They must also limit their fluid intake, since dialysis only removes so much water from the patient’s body. Infection is also an ever-present specter, since a permanent access point must be created in the body for either dialysis procedure.

Advantages and disadvantages

Deciding on a dialysis plan

If dialysis is recommended for you, you will have to decide whether you want to have haemodialysis or peritoneal dialysis.

Both methods have the same levels of clinical effectiveness, so the choice is usually a case of personal preference. However, there may be some circumstances where peritoneal dialysis is not recommended – for example, where a person is visually impaired or has dementia.

It should be stressed that any decision that you make about which treatment method to have will not be final, and you can choose to move from one treatment option to another.

Haemodialysis

Disadvantages

Haemodialysis usually involves using the dialysis machine three times a week, with each dialysis session usually lasting for about four hours.

Therefore, the obvious disadvantage of haemodialysis is that, to a large extent, you will have plan your life around your dialysis sessions. For example, if you were to travel to another country you would have to pre-arrange access to dialysis facilities.

Another disadvantage of haemodialysis is that your diet, and the amounts of fluid that you drink, will need to be restricted. For example, many people receiving haemodialysis have to avoid foods that are high in potassium, such as bananas, chocolate, and crisps, and are usually advised not to drink more than a couple of cups of fluid a day .

See the ‘how it works’ section for more detailed information about diet and fluid intake.

Advantages

The main advantage of haemodialysis is that, unlike peritoneal dialysis, you will be able to have four ‘dialysis-free’ days a week.

Haemodialysis – home or hospital?

If you decide to choose haemodialysis, you have the option of having a haemodialysis machine installed in your home. This means that you will not have to make regular visits to a dialysis unit.

There are a number of criteria that usually have to be met for home haemodialysis to be considered as a suitable treatment option. These include:

• you are physically and mentally capable of operating the dialysis equipment,
• previous sessions of dialysis have stabilised your symptoms,
• you are free of complications and do not have any other significant health conditions,
• there are no problems associated with using a catheter to gain access to your blood,
• you have a carer who has made an informed decision to assist you with the dialysis, and
• there is enough space in your home for a haemodialysis machine and the associated equipment.

If you fulfil these criteria, you still may not necessarily want to have home haemodialysis, and you will certainly not be pressured into having it.

Many people who are suitable for home dialysis still prefer to visit a dialysis unit because they find the attention and supervision of the staff both comforting and reassuring.

Also, many people find that having the haemodialysis machine in their house can be an unwelcome reminder that they have a serious health condition.

Before making a decision, you may wish to discuss the option of home haemodialysis further with your family, partner and/or other household members.

Peritoneal dialysis

Advantages

The obvious advantage of peritoneal dialysis is that, unlike haemodialysis, it does not require regular visits to a dialysis unit or, in the case of home haemodialysis, having a bulky machine installed in your house.

Also, the equipment that is used in peritoneal dialysis is portable, allowing you to travel with more freedom compared with if you were using haemodialysis. There are two main types of peritoneal dialysis equipment – one type is roughly the size of a hat stand on wheels, and the other type is the size and weight of a small suitcase.

Another advantage of peritoneal dialysis is that there is less restriction to diet and fluid intake compared with haemodialysis. People having haemodialysis are given a strict limit on the amount of fluids that they can drink (see below for more information).

Disadvantages

One of the main disadvantages of peritoneal dialysis is that you will need to perform it every day, whereas haemodialysis is usually only performed three days a week.

Another major disadvantage of peritoneal dialysis is that it increases the risk of your peritoneum becoming infected with bacteria (peritonitis). Peritonitis causes symptoms that include:

• abdominal pain,
• vomiting, and
• chills (episodes of shivering and cold).

Repeated episodes of peritonitis can damage the peritoneum and surgery may be required to repair it.

Another drawback of peritoneal dialysis is that the dialysis fluid that is used in peritoneal dialysis can cause a reduction in protein levels, which can lead to a lack of energy and, in some cases, malnutrition.

Some people using peritoneal dialysis also experience a raise in their blood cholesterol levels, which can put them at a greater risk of developing a cardiovascular disease, such as heart attack, or stroke.

Weight gain is another side effect of peritoneal dialysis that affects some people.

Peritoneal dialysis – continuous or automated?

There are two types of peritoneal dialysis:

• continuous ambulatory peritoneal dialysis (CAPD), and
• automated peritoneal dialysis (APD).

CAPD does not involve using a machine; it uses a portable set of equipment that includes a dialysis bag which contains fluid and a number of tubes.

With CAPD you will carry out regular dialysis sessions during the day; these sessions are known as exchanges because clean fluid is exchanged with fluid that contains waste products. Most people using CAPD will have four exchanges a day, with each exchange lasting between 30-40 minutes.

With APD you will use a dialyser machine, although the machine is much smaller than the one used in haemodialysis. Dialysis is performed during the night as you sleep, with a session lasting between 8-10 hours.

The main advantage of using CAPD is that the equipment is portable which allows you to have more freedom to travel away from your house. For example, there should be no reason why you cannot take your CAPD equipment to your workplace. However, you will need to spend at least two hours a day performing dialysis.

The main advantage of using APD is that your days will be ‘dialysis free’. However, you will need to keep and maintain a dialyser machine (and the associated equipment) in your house, which is a prospect that some people find off-putting.

How to take care of your kidney

1. Drink plenty of fluids.

We�ve all heard that drinking eight to ten glasses of water each day promotes better health, but do you know why? Imagine a riverbed that, due to a drought, sinks to low levels and even exposes muddy areas in spots. Debris like tree limbs, large stones, and even flailing fish can be seen floating in the lifeless stream and perhaps sticking to the banks in passing around bends. Then imagine a reservoir with low water levels. It may look dry, dusty, or shallow, with many objects bobbing on the surface that otherwise might be carried off downstream. This grim image is a picture of your bloodstream and kidneys when you don�t drink enough fluids. Although the kidneys act as more of a filter than a reservoir, toxins can build up if there isn�t enough water pressure to push them through to the urinary tract for excretion.

2. Avoid caffeine.

While a couple of cups of tea or coffee, and a little bit of chocolate, may not be bad for most people, don�t get hooked on drinking multiple cups ofcaffeine beverages each day. Your kidneys will be forced to work harder and pump out fluid and toxins when they become dehydrated by caffeine�s purging effect and more active by its metabolism-boosting powers. If you find that you are urinating several times a day more than you used to, try cutting back on caffeine products to see if that helps. Too much caffeine isn�t good for your body in many ways, and kidney stress is one of them.

3. Cut back on bumpy road rides.

Long-distance truck drivers may have a higher incidence of kidney bruising or damage than people in other occupations. Until the possible link is confirmed or disproved, try to take long rides in comfortable seats, and stop for frequent breaks to get out of the vehicle and stretch your legs, which will be good for your back as well as your kidneys and other organs.

4. Eat cleansing foods.

Some experts believe that cranberry juice helps to reduce bacteria in the urinary tract by keeping it from sticking to tissues where it can build up and cause an infection. A few glasses of this refreshing beverage each week might be enough to promote better kidney health. Some practitioners claim that white rice is a good food for cleansing the body. You may want to include this in your diet on occasion, as well.

You will feel better about taking control of your health when you use tips like these to protect your kidneys.