Chronic kidney disease
If the kidney function is decreased for more than three months and the glomerular filtration rate (GFR) has dropped to less than 60 millilitres per minute per 1.73 m2, this is called chronic kidney disease (CKD). It is also called chronic renal insufficiency or chronic kidney failure. There is no cure for chronic kidney disease. However, it is often possible to slow the loss of kidney function and minimise the associated risks. Therefore, early detection is extremely important. This way, the causes of kidney disease, such as high blood pressure or diabetes mellitus, can be treated in a timely fashion.
Symptoms of Chronic Kidney Disease
The onset of chronic kidney disease is usually insidious and it may not cause any symptoms at first. However, over time as the kidneys become less able to filter the waste fluid and toxins from the blood, the following symptoms might appear:
- Swelling (oedema), especially in the legs and eyelids
- Weakness and fatigue
In the advanced stages of CKD, further symptoms may occur:
- Anaemia and associated exhaustion, concentration problems and pallor
- Loss of appetite
- High or poorly adjustable blood pressure
- Shortness of breath
- Reduced urine output or passing urine more often overnight
- Bone pain
- Muscle cramps
- Itching of the skin and burning in the legs
- Nausea, vomiting, diarrhoea
Advanced kidney disease affects many other organ systems including:
- The cardiovascular system, increasing the risk of stroke and heart attack.
- The nervous system, increasing risk of cognitive impairment or poor memory.
- The musculoskeletal system, causing bone pain and sometimes fractures.
- The haematological system, causing anaemia.
Diagnosis of Chronic Kidney Disease
The glomerular filtration rate (GFR) indicates the stage of renal insufficiency. The GFR indicates the plasma volume that is filtered by the kidneys within one minute and is calculated from the creatinine level in the blood. In addition to the blood, the urine must also always be examined. Urine diagnostics help to detect a developing renal insufficiency and to identify its causes. Imaging such as ultrasound or computer tomography can also provide very useful information about kidney disease.
In stage 1, the GFR is still normal; it measures more than 90 millilitres per minute. However, if increased albumin levels are found in the urine, called albuminuria, this may indicate early kidney damage. An ultrasound examination of the kidneys provides information about possible changes in size, position and structure of the kidneys as well as about the renal blood flow.
In stage 2, the GFR has decreased to between 60 and 89 millilitres per minute. However, often symptoms are absent.
In stage 3, the GFR ranges between 30 and 59 millilitres per minute. Creatinine and urea levels are increasing, the blood pressure is rising, and patients are often more easily tired and are less resilient.
In stage 4, the GFR is only 15 to 29 millilitres per minute. The symptoms may become more severe. The patient may experience nausea, vomiting, itching, pain in the nerves and bones and swelling of the legs and face. Although it is still possible to be relatively asymptomatic at this stage.
In stage 5, the GFR drops below 15 millilitres per minute and chronic kidney disease has reached or is approaching end-stage kidney disease where the patient is dependent on regular dialysis or a kidney transplant. It is possible to have stage 5 CKD and not yet need to have dialysis or a kidney transplant.
Causes of chronic kidney disease
The most important and frequent causes of chronic kidney disease include high blood pressure and diabetes mellitus. Inflammation of the kidney tissue or repeated inflammation of the renal pelvis also reduces the filtering capacity. Other causes of chronic kidney insufficiency are congenital kidney diseases, cystic kidneys and calcification of the kidney vessels, and arteriosclerosis. The urinary tract can also become obstructed or blocked, for example, by stones or by compression. This can usually be identified on imaging and treatment should be aimed at relieving the blockage. Anyone on long-term medication may need to have their kidney function monitored and your doctor would be able to guide you in this regard.
Treatment of chronic kidney disease
It is imperative to treat any underlying disease that is believed to have led to kidney damage.
Those suffering from diabetes and/or high blood pressure should control their blood sugar and blood pressure values as thoroughly as possible. The doctor will provide advice and prescribe medication, where appropriate. A healthy lifestyle is equally important. A balanced diet and regular exercise can contribute significantly to an improvement in kidney function. Physical exercise, as simple as regular walks, can, for example, help to lower blood pressure, strengthen the muscles and consequently improve the quality of life. In many centres, there are even bicycles for dialysis patients so they can exercise during dialysis.
In the case of advanced kidney disease, patients should discuss their eating and drinking habits with their doctor. If kidney function is already severely reduced, salt, i.e. sodium chloride should be used carefully. Attention may need to be paid to other elements of the diet, particularly the potassium and phosphate content. Dialysis patients, in particular, are often asked to avoid foods with a high content of these minerals. It is sometimes possible to modify cooking methods to reduce the content of potassium and phosphate in food. However, guidance on diet should always be sought from the doctor and or dietician caring for the patient. Foods which are high in potassium include, but are not limited to chips, bananas, tomatoes, coffee, chocolate and dried fruits. Dairy produce and nuts have a higher phosphate content. It is important also to note that dietary salt is not usually an alternative for patients with kidney disease because although it contains little sodium, it is rich in potassium.
If the kidneys are no longer able to remove wastes from the blood, detoxification must be ensured in another way, via dialysis or a kidney transplant.