Chronic kidney disease

What is chronic kidney disease?

Chronic kidney disease means that the kidneys no longer work adequately over a longer period of time and lose some or all of their function. The bean-shaped organs are small high-performance organs that fulfill vital tasks in the body:

• They work like a “cleaning factory“, filtering waste and toxins out of the blood and transporting them out with the urine.
• They also regulate the acidity of the blood as well as the water and electrolyte balance. If there is a lack of fluid, they retain water in the body, but if there is an excess of fluid, the reverse happens: The kidneys excrete more water via the urine. They also control the amount of electrolytes in the body, for example sodium or potassium, through similar processes of retention and excretion.

In chronic kidney disease, these processes no longer run smoothly and completely because the kidneys are weakened or damaged. Waste and toxins from the metabolism then accumulate in the blood and also disrupt the function of other organs.

Sick kidneys – different terms

Experts distinguish between acute renal failure, in which the kidneys suddenly stop working. However, they often recover if we treat the disease adequately. The causes of acute renal insufficiency are often significant injuries with major blood loss or circulatory failure.

The collective term chronic kidney disease (CKD) covers stages in which the kidneys still function to a limited extent, but their activity is reduced for more than three months. The causes are often high blood pressure and diabetes mellitus. Older people are particularly affected. Chronic kidney disease often goes unnoticed for a long time because it hardly causes any symptoms.

Chronic renal insufficiency, on the other hand, usually refers to the final stage of a process in which kidney function has continued to deteriorate – to the point of kidney failure.

Chronic kidney disease – frequency and age

The risk of chronic kidney disease increases with age. This is because, in general, the organs function more and more poorly with increasing age. The most common triggers are high blood pressure and diabetes mellitus, which also occur more frequently at an older age. Many patients with chronic kidney disease have to undergo dialysis (blood washing) because the kidneys’ cleansing function is severely impaired. According to the Swiss dialysis register, there were 4,453 dialysis patients in 2015. On average, they were 68 years old, but every second person was older than 71.

Chronic kidney disease: often caused by two common diseases

The causes of chronic kidney disease are often other diseases. These include two diseases that are common in the population:

1. High blood pressure (hypertension): Long-term high blood pressure generally damages the blood vessels. However, the glomeruli – the fine vascular clusters in the renal corpuscles that act as “mini-filters” – are also affected.
2. Diabetes mellitus: A permanently elevated blood sugar level damages the blood vessels in many organs – including the kidneys. Diabetic nephropathy is the name of the disease.

There are also several other possible causes of chronic kidney disease:

• Glomerulonephritis: These are inflammatory diseases of the renal corpuscles, in which the vascular clusters (glomeruli) for blood purification are located. Glomerulonephritis can be triggered by autoimmune diseases in which the immune system attacks the body’s own structures, but also by cancer. Glomerulonephritis is particularly common in young adults.
• Medication, for example painkillers such as paracetamol, ibuprofen or diclofenac, which you take over a longer period of time. However, some antibiotics, cytostatics (for cancer) or iodine-containing contrast agents can also affect the kidneys.
• Congenital kidney diseases, for example cystic kidneys – from around the age of 40 – can trigger chronic kidney disease.
• Chronic pyelonephritis
• Kidney stones
• Tumors or scars in the kidney that interfere with urine flow

Symptoms: Chronic kidney disease often goes unnoticed for a long time

Chronic kidney disease often only becomes noticeable at a late stage. As long as kidney function is only slightly impaired, most people do not experience any symptoms. Sometimes doctors discover kidney disease by chance during a routine check-up, for example when they determine kidney values. However, this changes when the kidneys function less and less well over time.

Various signs can indicate chronic kidney disease and a type of “internal poisoning” (uremia) when the kidneys no longer sufficiently cleanse the blood of waste and toxins. The blood also reaches other organs, which explains the variety of symptoms:

• Initially: increased urge to urinate, frequent visits to the toilet
• Water retention in the tissue (edema) and swelling; shortness of breath when the water accumulates in the lungs – the body becomes overhydrated
• High blood pressure: The body excretes too little water and the pressure in the blood vessels increases.
• The breath smells of urine.
• Light brown spots on the skin (“café au lait spots”)
• Tiredness, fatigue
• Reduced physical and mental performance, concentration disorders
• Headache
• Pallor due to anemia caused by kidney disease (renal anemia) – the kidneys are involved in the formation of red blood cells
• Loss of appetite
• Nausea, vomiting
• Diarrhea
• Itching
• Muscle weakness and cramps, signs of paralysis
• Reduced urine output

Chronic kidney disease: diagnosis with us

The tricky thing is that chronic kidney disease hardly causes any symptoms at first. This is why we often discover them by chance as part of a routine examination, for example when determining kidney values. Anyone who already suffers from high blood pressure or diabetes should have these values checked more often, as the risk of chronic kidney disease is increased.

The diagnosis of chronic kidney disease always begins with a medical history interview. For example, we have the following questions:

• What complaints do you have, since when and how pronounced?
• Do you suffer from high blood pressure or diabetes?
• Do you have any other known illnesses?
• Do you have a family history of kidney disease?
• Have you already been diagnosed with kidney damage by doctors?
• Do you take any medication? If yes: which ones and since when?

This is followed by a physical examination, during which we check the condition of the skin, for example, and detect any water retention. A blood pressure measurement (also over 24 hours) shows the pressure in your blood vessels. An ultrasound examination (sonography) allows us to determine the size of the kidneys and the condition of the kidney tissue. Very small kidneys are an indication that the kidney disease has been present for some time. Further examinations are carried out if chronic kidney disease is suspected:

• Blood test: If the kidneys can no longer filter the blood sufficiently, creatinine and urea accumulate there. The higher the values, the worse the kidneys are working. However, the creatinine value only provides an initial assessment because it only rises when kidney function has already fallen by around half. We therefore use the creatinine clearance. The value shows how quickly the kidneys can filter creatinine out of the blood. The urine is collected over 24 hours, then the creatinine value is determined simultaneously in the blood and urine. We also calculate the glomerular filtration rate (GFR), usually from the creatinine value. The GFR indicates the volume filtered by the glomeruli of the kidneys per unit of time.
  But the blood reveals even more. For example, we determine white blood cells, the inflammation marker C-reactive protein (CRP), liver values, blood lipids or electrolytes such as calcium and phosphate.
• Urine test: A rapid urine test using a test strip provides initial indications of kidney disease. The amount of proteins and blood cells in the urine is measured. If the test result is abnormal, a more detailed urinalysis will follow. Healthy kidneys filter proteins from the blood so that they are not found in the urine, or only in very small quantities. Therefore, the determination of proteins in the urine allows conclusions to be drawn about the filter function of the kidneys. If increased quantities are found there, this is an indication of damaged kidneys. The urine is collected over 24 hours and then analyzed in the laboratory. Protein excretion in the urine can also be used to monitor existing kidney disease. The urine sediment shows whether red or white blood cells are present in the urine. The analysis is carried out under a microscope.
• Tissue sample: Sometimes doctors take a tissue sample (biopsy). These are then examined under a microscope by a laboratory technician. It shows the composition of the kidney tissue as well as abnormalities and changes.
• Scintigraphy: The clearance can be calculated very precisely using scintigraphy with the substance DTPA. In addition, the relative performance of both kidneys can be displayed separately.

Chronic kidney disease: prevention, early detection, prognosis

Chronic kidney disease has two main causes: High blood pressure and diabetes mellitus. There are a number of risk factors that you can influence yourself to a certain extent. Some tips:

• healthy and balanced diet
• Avoid being overweight
• A lot of movement
• Moderate alcohol consumption
• No smoking

In this way, you may also be able to prevent chronic kidney disease.

In addition, if you have high blood pressure or diabetes, make sure you take adequate medication to treat high blood pressure and high blood sugar levels. You should also have regular check-ups. In this way, chronic kidney disease can often be detected at an early stage.

Do not take (often over-the-counter) painkillers such as paracetamol, ibuprofen or diclofenac on your own over a longer period of time. They can damage the kidneys. Always discuss the intake with us.

Progression and prognosis of chronic renal failure

The course and prognosis of chronic kidney disease always depend on the stage of the disease and the extent to which kidney function has already been impaired. The glomerular filtration rate (GFR) serves as a measure for this. It indicates how well (at what speed) the vascular clusters in the renal corpuscles (glomeruli) can still filter the blood. The more kidney tissue is damaged, the slower the kidneys work.

For example: healthy kidneys in women produce 74 to 125 milliliters of blood per minute, in men it is 95 to 145 milliliters. In the case of chronic kidney disease, it is only 60 milliliters per minute or less.

Experts distinguish between the following stages:

• Stage 1: Although the kidneys are already damaged, they still function normally.
• Stage 2: Kidney function is slightly impaired (GFR = 60 to 89 ml).
• Stage 3: Kidney function is moderately impaired (GFR = 30 to 59 ml).
• Stage 4: Renal function is severely impaired (GFR = 15 to 29 ml).
• Stage 5: The kidneys fail (GFR < 15 ml).

Not only the stage of the kidney disease plays a role in the prognosis, but also the age, other concomitant diseases and your adherence to treatment (compliance). By this, experts mean how consistently you carry out a treatment.

In general, it can be said that kidney disease detected at an early stage has a better prognosis than a late stage. As the disease progresses, many people have to undergo dialysis to “fish” the waste and toxins out of their blood. Although this means some restrictions in everyday life, it extends life expectancy. Sometimes only a kidney transplant can help – after which many can lead a normal life again. However, the waiting lists for donor organs are long in many countries.

Complications of chronic kidney disease

If the kidneys function increasingly poorly, this can have far-reaching consequences for the entire body. The following complications are possible:

• Heart attack (myocardial infarction) and stroke (cerebral infarction): High blood pressure plays a central role in both diseases. In addition, the electrolyte balance (e.g. potassium, sodium, phosphate) becomes unbalanced, which is also harmful to the heart and circulation.
• Acidosis of the organism (acidosis): Healthy kidneys can neutralize the acids in the blood that are produced when proteins are broken down – in the case of chronic kidney disease, this is no longer sufficient. Symptoms: Nausea and vomiting. In the long term, the bones suffer particularly from hyperacidity.
• Bone damage: Healthy kidneys convert vitamin D, which is important for strong bones, into its active form – calcitriol. It ensures that the mineral calcium is incorporated into the bones. If the kidneys are weakened, less calcitriol is available and the bones receive less calcium – they become weak and brittle.
• Nerve damage: When kidney function is impaired, waste and toxins accumulate in the blood, which are produced during metabolism. And these can also damage the nerves and disrupt brain functions.
• Psychological problems: Anxiety, sleep disorders or depression are not uncommon, because a chronic illness affects not only the body but also the mind.

Self-help groups

The exchange with people who are affected by the same disease can be a great support in coping with the disease. Advice on finding a suitable self-help group is available from Selbsthilfe Zürich. Self-Help Zurich and the University Hospital Zurich are cooperation partners in the national project “Health literacy thanks to self-help-friendly hospitals”.

Chronic kidney disease: treatment slows progression

The treatment of chronic kidney disease aims to slow its progression. Through the therapies, we try to ensure that kidney function does not deteriorate rapidly and that the kidneys eventually fail completely. Chronic kidney disease cannot be cured because the kidney tissue cannot be regenerated. Treatment usually addresses the two main causes of chronic kidney disease – namely high blood pressure and diabetes mellitus. But you can also do something yourself to prevent your kidney function from deteriorating any further. Avoid all substances that have kidney-damaging effects. Examples include painkillers such as non-steroidal anti-inflammatory drugs (e.g. ibuprofen, diclofenac), nicotine, certain antibiotics and iodine-containing X-ray contrast media.

• Nutrition
• Treat causes
• Treat complaints
• Blood washing (dialysis)
• Kidney transplant