Nephropathy – Kidney Failure in Diabetes
|In New Zealand, over 40% of all patients requiring renal replacement therapy – i.e. dialysis or a transplant – are as a result of the damaging effects of diabetes. This is about on par with average figures for ‘westernised’ countries including the UK and US (figures range from about 40 – 50%, depending on source data)
However, importantly, research data suggests that Maori and Pacific peoples are 3.5 times more likely to develop kidney failure.
The story doesn’t end here; numbers are expected to increase dramatically over the next ten years… Clearly, diabetic kidney disease is a problem affecting individuals and nations, and it requires attention.
End stage renal failure (ESRF) is diagnosed when the kidneys can no longer function sufficiently well to keep the person alive. At this stage, either dialysis or a kidney transplant are the only options. It can take up to 10 years or longer to progress to ESRF – this depends on many individual factors including:
- Blood glucose control
- Blood pressure control
- Co-existing disease such as heart disease or renal artery disease
- Hereditary factors
|End stage renal failure is not inevitable for all people with diabetes that have been diagnosed with nephropathy. It is a real possibility for some, but – as with most medical conditions – your outcome will depend on your personal combination of indivdual factors relating to your genes and your environment.
Some factors are modifiable – meaning that you can influence the outcome by changing things. Such factors are usually ‘environmental’ factors.
However, some circumstances are always beyond our control. The most we can do is learn how best to deal with the situations that we are presented with.
ESRF is by no means “The End”. I fully recommend that you take a look at the recommended book (see Table of Contents above). Read it from cover to cover; you are sure to be both surprised and inspired.
With modern medical technologies many people with ESRF are now continuing to live full and rewarding lives, maintaining a balance between kidney disease and diabetes on the one side, and life on the other.
Early on, kidney disease does not tend to result in symptoms; only when the kidneys are seriously failing do symptoms become apparent.
|Symptoms of End-Stage Renal Failure (ESRF)
In addition to your usual “diabetic diet” there are additional considerations for kidney patients, particularly with advancing kidney failure.
Dietary guidelines are individualised and may change as the course of kidney disease progresses and your medical circumstances change.
As a starting point, basic healthy eating guidelines should be followed by all people:
HEALTHY EATING FOR EVERYONE
Additional considerations may include the following:
Various degrees of malnutrition are common in people with end-stage renal disease (ESRD). Both anorexia (defined as reduced apetite) and a catabolic state leading to loss of protein from skeletal muscle and other tissues are observed. Evidence suggests that an interaction between inflammatory and other factors – including central nervous system regulation of appetite, co-morbidies, acidosis, anaemia and hormonal derangements – combine to produce both anorexia (loss of appetite) and cachexia (wasting due to chronic illness).
Nutritional status can be determined by
- assessing eating and drinking habits/patterns
- albumin (protein) level in the blood
- patients muscle size
- monitoring body weight
Loss of appetite is one of the key sympoms in kidney failure. As the disease progresses, this may become more apparent. Appetite for certain foods may change. Some foods may taste different (often meat products) and a metallic taste may persist in the mouth.
|The kidneys, when functioning normally, play a major role in getting rid of many of the “toxic wastes” which come from the digestion of food. When the kidneys are unable to function normally and the “toxic wastes” which come from the digestion of food begin to build up in the body, many patients develop a bad taste in their mouth. This is referred to as uremic or ammonia taste.
Dialysis should restrore appetite to near-normal, but unfortunately it is often not sufficient to rid the body of the appetite-supressing toxins
Severe anaemia, a common complication of kidney disease, may also depress the appetite.
Calcium and Phosphate
- Calcium supplements may need to be taken
- Phosphate intake may need to be limited
In kidney failure, the body’s ability to control blood levels of potassium is lost. Potassium intake may need to be adjusted accordingly. (increased or decreased depending on test results)
- Salt restriction usually necessary for two reasons:
- to aid in blood pressure control
- to avoid unnecessary thirst (see below)
- use little or no salt at the table and in cooking
- avoid processed and salty convenience foods
Haemodialysis patients may need to rstrict fluid intake to a greater degree than PD (why?)
Some guidelines suggest about 1 litre for people on Haemodialysis, or 1.5 litres for people on Peritoneal Dialysis.
Fluid advice is individualised, and tends to be based on whether the kidneys are making any urine, and if so, how much – as a general rule, the more urine you make the more you can drink
As a generalisation, dialyis patients can usually drink 500 – 750 mls fluid per day plus whatever their urine output is the previous day.
After a transplant no specific fluid or dietary restrictions usually necessary, – apart from usual healthy eating approaches aimed at blood glucose and blood pressure control.
water-soluble vitamins (esp B and C) are lost during dialysis and supplementation of these may be recommended.
Protein intake may need to be increased during dialysis because of the increased risk of malnutrition
– this recommendation usually superceeds the ‘worry’ that eating protein causes the blood urea level to rise.
Protein supplements may be useful.
There is no cure and no going back once you have kidney failure. If you wish to survive then you need to start dialysis – and the sooner the better.
Dialysis is an artificial way of cleansing the blood and removing excess water from the body – it aims to replace the life-maintaining work of the kidneys. Dialysis does not reproduce all of the functions of the kidney, but it does relieve most of the symptoms that develop in end-stage renal failure.
There are two different types of dialysis – peritoneal dialysis and haemodialysis – these both work in similar ways to clean the blood (see box below) but are quite different in practical terms for the patient.
How does dialysis work?
Waste products are removed from the blood by diffusion
Excess fluid (water) is removed is removed by ultrafiltration
Waste and excess water pass into the dialysis fluid
A thin layer of either plastic or tissue forming the dialysis membrane separates the blood and dialysis fluid
Dialysis also provides the opportunity to replace any substances that may be lacking – calcium or bicarbonate, for example.
Dialysis can replace only 5 percent of the function of two normal kidneys; however, this is usually sufficient to relieve the symptoms of kidney failure, and enable the person to life a reasonable quality of life (let me know if you disagree with this!), and often to return to work.
The short answer to this is, “Sooner, rather than later.” Why? Because once you reach the final stage where your kidneys are failing badly, you are likely to be suffering from a number of symptoms (see above). Once you start dialysis you are guaranteed to feel a whole lot better.
There are two basic types of dialysis. Both methods work on the same principle, but in a practical sense they differ greatly. Some people are much better suited to one form over the other, however this frequently depends on persenal preferences, lifestyle, and work or family commitments.
Peritoneal dialysis (PD) takes place inside the person’s body using the natural lining of the abdomen (the peritoneum) as the dialysis membrane. It requires a huge commitment from the patient, because it is performed by the patient at home (or work) several times per day.
Haemodialysis is the ‘traditional’ and better known form of dialysis, which takes place outside the body. It only needs to be performed about 3 times per week, however each session lasts from 3 to 5 hours, and is usually performed at the hospital dialysis unit.
Haemodialysis requires repeated access to the person’s bloodstream, and setting this up might prove to be a problem in some people with diabetes because of narrowed blood vessels.
Additionally, the use of heparin is not always a good option for people with diabetes because it may promote bleeding in the back of the eye (see sections on retinopathy) AND CHECK! ALSO CHECK RE HEART DISEASE PAGES
A sudden change in blood pressure can occur as excess fluid is removed from the body during dialysis. This can be problematic for people with diabetes undergoing haemodialysis, particularly if autonomic neuropathy affects the person’s heart function.
PD is sometimes the preferred option for people with diabetes, although frequently this will depend upon on locally or regionally determined factors.
If you are on the transplant waiting list then you may have to wait two years or longer for a kidney to become available. During this time you will need to have dialysis on a continuing basis in order to stay alive. in New Zealand?!
Haemodialysis is the name given to the traditional type of dialysis, which is performed outside the body by a dialysis machine (“kidney machine”, or “artificial kidney”). Blood is pumped through the dialyser, along with dialysis fluid and water.
Some substances are able to pass either one way, or the other, into or out of the dialysis fluid. Blood cells cannot pass through and stay in the blood as it flows through the dialysis machine.
The blood entering the dialysis machine tends to be high in toxic wastes, and is sometimes low in calcium and bicarbonate. The blood leaving the dialysis machine and going back into the patient has had the toxic wastes removed; excess water is also removed, and the fluid balance restored to near-normal; and, depending on the dialysis solution used, levels of various substances, such as calcium and bicarbonate, are corrected.
Figure 1 – Haemodialysis
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Heparin (a thinning agent) is usually added to the blood in order to reduce the chances of it clotting.
Blood samples before and after dialysis, and sometimes samples of the dialysate (the dialysis solution leaving the machine) are often sent to the laboratory to be tested for various markers to ensure that the dialysis has been effective. (See, the section on “Specialist Care” for more on tests related to dialysis.)
After 3 or 4 hours, all of a person’s blood will usually have passed through the kidney machine several times, and should be well cleansed. The procedure tends to take up a whole morning, afternoon, or evening and you will need to have 2 or 3 sessions of haemodialysis per week.
Haemodialysis was traditionally performed inhospital at a regional renal unit. However, there are an increasing number of satellite dialysis units now being resourced in New Zealand. It is also becoming increasingly possible to have haemodialysis at home.
One way to access the blood supply for haemodialysis is the arteriovenous fistula (AVF, or simply “fistula“). This is set up several weeks before haemodialysis is due to begin. In a small operation – which may be performed under a local or a general anaesthetic – a vein is joined to an artery in one of the arms, usually at either the wrist or the elbow.
Arteries carry “fresh” oxygenated blood away from the heart to various organs and tissues throughout the body. Veins carry “used” blood back to the heart. The blood pressure in arteries is always higher than that in veins; at the fistula, blood will flow from the artery into the vein and, after a while, the vein will enlarge providing easy access for the two needles to be inserted into during a dialysis session. (Yes, two needles are required – one needle takes blood to the dialysis machine and the other returns ‘cleansed’ blood from the dialysis machine)
Potential problems with a fistula
Steal Syndrome – Reduced blood supply to the hand – normally people do not notice that some of their arterial blood supply has been diverted away from the hand. However, sometimes this can result in a cold or painful hand. Talk your dialysis unit if this is troubling you.
Clot – normally a buzzing sensation can be felt if the fistula is touched (“bruit” pronounced broo-ee); if a clot forms in the fistula this sensation is lost.
Some fistulas do not develop into a vein that is large enough for adequate blood flow. New fistulas or grafts can be made, but after a number of years it is possible to ‘run out of’ suitable veins.
An alternative way to provide access is by using a catheter or ‘haemodialysis line‘. (Sometimes this is referred to as a Tesio catheter. A double-ended plastic tube (catheter) is inserted into a major blood vessel. The catheter remains ‘half-in/half-out’ and requires a special dressing in between dialysis treatments.
Access points include the jugular vein in the neck, the subclavian vein at the top and at one side of the chest, and the femoral vein at the top of the thigh.
A catheter may be used for temporary access whilst a fistula is healing.
The tubes enable access for haemodialysis without the use of needles, which makes it sound like an attractive option for some people. However, the catheter is not as reliable as the fistula in the long term.
Fistulas tend to be the preferred option for haemodialysis because they do not use any plastic and are therefore less susceptible to infection. However, creating a fistula can be more problematic in people with diabetes due to damaged blood vessels; a permanent catheter may be a better prospect in such people.
|When catheters and fistulas fail
Alternative types of access are possible if the more usual methods fail for some reason:
Potential problems with haemodialysis
Other problems that may occur include the following:
Fluid overload – This is the opposite of dehydration; patients may need to restrict the amount of fluids that they drink in order to avoid this problem. Excess fluid may collect in the ankles, under the skin and eventually in the lungs. Ultimately blood pressure may rise.
High potassium – Hyperkalaemia – Too much potassium in the blood can cause the heart to flutter, or even to stop beating altogether. If raised levels of potassium are a continuing problem, it may be necessary to restrict dietary potassium intake (see above).
Access problems – Dialysis catheters may become blocked by a clot, or become infected. Narrowed blood vessels in people with diabetes can also cause problems with access for haemodialysis.
Bleeding – The use of heparin in haemodialysis increases the risk of bleeding either during or after dialysis.
Peritoneal dialysis (PD) takes place inside the person’s body using the natural lining of the abdomen (the peritoneum) as the dialysis membrane. The dialysis fluid is drained into the abdominal (peritoneal) cavity and left there for a few hours* (see footnote). It is then drained out again – containing wastes that have moved in from the bloodstream – and a fresh bag of dialysis fluid is drained in.
PD requires a huge commitment from the patient, because the exchanges are performed by the patient at home (or work) several times per day. PD may not be suitable for people who are unable to care for themselves (if they do not have full-time access to someone to help them). Training is usually provided though, and your renal care team will ensure that you are confident in the procedure before leaving the responsibility in your hands.
Before PD can start, a minor operation is needed to insert the PD catheter – this is a plastic tube, about the size (diameter) of a pencil, that is permanently inserted into the abdomen.
There are essentially two types of PD, which differ only in the way that the fluid is “exchanged”. In Continuous Ambulatory Peritoneal Dialysis (CAPD) the dialysis fluid exchanges are performed the patient several times throughout the day. In Automated Peritoneal Dialysis (APD) the exchanges are performed automatically by a machine several times during the night.
* Footnote The length of time between “exchanges” depends on an individual’s requirements and the type of PD being performed.
Potential problems with PD
Enlarged abdomen – After a while the abdomen becomes stretched by PD, and takes on a swollen or rounded look. Young women are sometimes overly concious of their body shape. Exercises to strengthen and tone the abdominal muscles may help.
Fluid overload – This is the opposite of dehydration; patients may need to restrict the amount of fluids that they drink in order to avoid this problem.
Drainage problems – The PD catheter can sometimes become blocked. If the catheter moves out of it’s normal position the fluid may not drain properly. Problems with drainiage also occur if the bowel presses on the catheter – avoid constipation.
Infections – Infections within the abdominal cavity may cause peritonitis. This can cause the drainage fluid to be cloudy. Infections at the area where the catheter comes out through the skin are problematic for some people (“exit site” infections).
If successful, a kidney transplant is a much more effective treatment than continued dialysis.
126 kidney transplants were performed in New Zealand last year (2007) – 68 of these were with kidneys from deceased people (cadaveric) and 58 of these were kidneys from living donors.
If you are on a waiting list for a new kidney you may not be given much notice that a kidney is available for you. This means that you need to be prepared to go into the hospital at short notice; you could be contacted any time, day or night. If you are not available when the kidney becomes available it may go to someone else.
In New Zealand, (and all around the world) there are more people waiting for organs than there are organs available for transplantation. Some people will wait a number of months for a transplant while others will have to wait a number of years for an organ to become available. According to Organ Donation New Zealand, more than 400 New Zealanders are waiting for an organ transplant and approximately 350 of these are waiting for a kidney transplant. The average wait for a cadaveric kidney in New Zealand is two to three years. The length of time you spend on the waiting list can vary. Kidney allocation depends on matching of blood and tissue type as well as on length of time on the list.
A successful transplant requires a “good match” – this means that the tissue of the donor kidney is of a similar type to your own. Your tissue type and blood group must be determined and compared to that of potential donors.
Living related transplants (LRTs) are sometimes the best option in order to jump the waiting the waiting list and avoid long-term dialysis. However, the process of obtaining a transplant kidney from a living donor is not quite as simple as it sounds; it requires careful consideration on the part of donor and recipient and close family relatives in each case.
Transplant units and tissue banks
Transplant units are responsible for the retrieval and transplantation of the donated organs.
The tissue banks are responsible for assessment of the donated tissue and for the storage of the tissue until it is transplanted.
Some last minute checks are necesary before the operation can go ahead:
- Health status – You will be given a thorough check-over before the operation in order to make sure that you are fit and well enough. If you have a bad cold, for example, the operation may have to be delayed until another time.
- Cross-match – This is a final blood test that is perfomed in order to see what the chances are of your body’s immune cells attacking the foreign donor’s cells when they are introduced into your body. A sample of your blood is mixed with a sample taken from the donor’s lymph nodes to see if any antibodies react.
The operation lasts about 3 hours, and requires a general anaesthetic. See page on “Surgery” in the section, “Your Diabetes Care” for information on diabetes management during surgery and stays in hospital.
The new kidney comes complete with a renal artery which will take blood into the kidney, and a renal vein, through which blood will leave the kidney. It also has a ureter, which will take urine to the bladder.
A cut is made below the navel, to one side; the new kidney is placed in the lower part of the abdomen (your two existing kidneys remain in place).
The artery and vein on the donor kidney are connected to your main leg (femoral) artery and vein on that side of the body.
The ureter attached to the new kidney is connected to your bladder, often with a small plastic tube – called a J stent – which helps to prevent blockages (this will probably be removed some months after the transplant).
When you fisrt come round from the operation you will be attached to a few tubes, in addition to the intravenous drip tubes:
For the first few days you will be monitored closely. You may be able to sit up and eat/drink small amounts the day after your operation.
Important indicators of the success of the transplant will be followed closely:
Sometimes the kidney does not start working immediately. You may need to resume dialysis and wait for the kidney to get going – this could take weeks or months, so don’t worry if it doesn’t happen immediately.
It may take 3 or more months before you have fully recovered from the operation and can resume “normal activities”.
In the UK transplant patients are recommended not to drive for at least a month after the operation. This is mainly because the act odf an emergency stop puts a great deal of physical presure on the lower abdomen area of the body. ?CHECK! AND FOR NZ
If the transplant fails, you may need to return to dialysis and go back on the waiting list to try another.
If all goes to plan, you may have a new kidney that will last you for the next 8 – 10 years. After that? Well, depending on your age, and general health, then you may be lining up for another kidney…
The rejection process is initiated by the body’s own immune system correctly determining that there is “foreign” material in its midst. It is a perfectly natural process, and a certain degree of rejection is common among transplant patients. The severity varies between people.
More About Rejection
Acute rejection – Short-term and/or rapid-onset; occurs during first few weeks or months & requires immediate medical attention.
Frequently that there are no “symptoms” as such directly related to rejection, apart from those caused by the continued kidney failure.
The drug methylprednisolone may be given intravenously on several occasions, usually spread over a number of days (“pulses”). This treatment can often suppress the rejection.
Alternative intravenous antibody medication may be tried if the methylprednisolone doesn’t work first time around; this is a highly successful therapy for the rejection process, but it can cause quite severe and unpleasant side effects (fever, pain, shortness of breath, diarrhoea) .
Long term rejection (sometimes called chronic rejection) – Occurs very slowly; the immune system doesn’t attack the new kidney in the same way as occurs in acute rejection. A decline in kidney function (blood creatinine levels going up) may be noted as long as a year or more after an apparently successful transplant.
Eventually, dialysis may need to be restarted; the length of time taken to reach this stage varies considerably.
Biopsy is the only way to verify what’s going on, if rejection is suspected.
All people who have organ transplants need to take immunosuppressant drugs for the rest of their lives. These drugs – as the name implies – suppress the immune system and are intended to deter the body’s immune system from attacking the new kidney. The problem with this approach is that it is obviously desirable to maintain the ability of the immune system to fight infection… the key is therefore in finding the balance that will prevent the rejection of the new kidney, whilst enabling the person to continue life in the real world which harbours numerous potential infections…
Your immunosuppressant drugs are vital for the success of your transplant; if you do not take them for some reason, or if you have sickness or diarrhoea and they are not absorbed into your bloodstream then you will need emergency medical care. Go to the hospital, or take action as pre-directed in such circumstances by your kidney specialist team.
One virus that transplant patients taking immunosuppressants are particularly susceptible to is cytomegalovirus (CMV). This usually causes mild flu-like symptoms, but may cause serious illness.
However, once diagnosed, a course of gancyclovir injections will soon have it sorted.