Chronic renal insufficiency

Overview: What is renal insufficiency?

Normally, a person has two kidneys. They are located in the posterior abdominal cavity directly below the rib cage. The kidneys are approx. 10 – 12 cm long, 5 – 6.5 cm wide and 3 – 5 cm thick. Each kidney contains about 1 million nephrons, which are the functional units. They filter the blood and produce urine. Metabolic products, electrolytes, water and other substances that the body no longer needs are excreted in the urine. Certain medicines, poisons or drugs also leave the body in this way. The urine produced in the kidneys flows via the renal pelvis and the ureters into the bladder, from where it is excreted via the ureters. In addition to their excretory function, the kidneys have other important tasks. They regulate:

• the fluid balance in the body
• blood pressure and
• the acid-base balance

They also produce important hormones such as erythropoietin, which stimulates blood formation. Vitamin D, which is important for bone metabolism, is also activated in the kidneys

Chronic kidney disease develops slowly

Various influences (see causes and risk factors) can lead to chronic damage to the kidneys. As a result, the excretory function decreases and the other functions can no longer be fully performed. Chronic renal insufficiency develops very slowly and typically goes unnoticed for a long time. As a sufferer, you will feel virtually nothing of thegradual deterioration. Only blood and urine tests can provide information about possible damage. In most cases, symptoms only occur when kidney function is severely impaired. Chronic renal insufficiency is often only discovered as a result of secondary diseases such as increased blood pressure. Unfortunately, in chronic renal insufficiency, once the cells have been damaged, they do not recover and the disease is progressive.

Causes and risk factors of renal insufficiency

The most common causes of chronic renal insufficiency are

• Diabetes mellitus
• Hypertension
• Inflammatory kidney diseases (glomerulonephritis)
• Hereditary kidney diseases such as polycystic kidney disease
• Damage caused by medication
• Chronic urinary flow disorders
• Repeated acute kidney damage

Diabetes mellitus is an important risk factor for chronic renal insufficiency. Over time, high blood sugar levels damage the fine vascular system of the kidneys. Doctors then speak of diabetic kidney disease. Unfortunately, between 40 and 50 percent of diabetics develop renal insufficiency over time, which can then develop into kidney failure. So if you have diabetes, you should make sure that your blood sugar is well controlled and that your kidney function is checked regularly.

High blood pressure damages the kidneys

High blood pressure strains the blood vessels – fine structures, such as those found in the kidneys, suffer first. High blood pressure is also one of the silent diseases; for a long time, sufferers do not notice anything. High blood pressure not only damages your kidneys, it is also the number one risk factor for cardiovascular diseases. If you have your blood pressure and cholesterol levels checked regularly, you will create good conditions for avoiding renal insufficiency and kidney failure as far as possible.

Use over-the-counter painkillers sparingly

You should be careful with over-the-counter painkillers for headaches and aching limbs and take them for as short a time as possible. The substances contained in the painkillers reduce blood flow to the kidneys and can cause permanent damage to the kidneys if consumed over a longer period of time. If prolonged use is necessary, this should take place under medical supervision. But not all painkillers damage the kidneys. Paracetamol, for example, is harmless to the kidneys.

Obesity as a risk factor

Your weight also plays a role as a risk factor for chronic kidney failure. Studies have shown that fatty tissue releases certain substances that lead to inflammatory processes and excessive filtration in the kidneys, which can damage the renal corpuscles in the long term, especially if there are other risk factors for chronic renal insufficiency. Smoking, in combination with other risk factors, can also promote the development of chronic kidney disease and accelerate its progression.

Symptoms of renal insufficiency

Chronic kidney disease or renal insufficiency does not lead to symptoms for a long time. Only when kidney function is far advanced can symptoms occur, but these are not specific to kidney disease. The first signs may be fatigue or adynamia. A sudden onset of high blood pressure can also be a sign of renal insufficiency. If swelling occurs due to water retention in the legs or face (edema), the family doctor should definitely examine the blood and urine for the presence of kidney damage. Loss of appetite, shortness of breath or generalized itching only occur when kidney function is severely impaired.

Protein in the urine is a sign of kidney damage

Increased protein excretion (especially the protein albumin) in the urine is a sign of kidney damage regardless of kidney function. It can indicate kidney damage if the function is still normal. The doctor can determine whether your kidney function is impaired by measuring creatinine or cystatin C in your blood.

Diagnosis of renal insufficiency

As chronic renal insufficiency is initially asymptomatic, the following risk groups should be examined regularly (at least once a year) by the family doctor by determining creatinine in the blood and the albumin/creatinine ratio (ACR) in the urine:

• Diabetes mellitus
• Arterial hypertension
• Cardiovascular diseases
• Obesity
• Systemic diseases that predispose to chronic kidney disease (hepatitis B/C, HIV, lupus, vasculitis)
• Treatment with drugs that damage the kidneys
• History of acute kidney damage
• Chronic/hereditary kidney disease in the family

Chronic kidney disease is present if kidney function is impaired (calculated from the creatinine) and/or albumin excretion is increased over a period of more than 3 months. To find out the cause of chronic kidney disease, further laboratory tests of blood and urine as well as an ultrasound examination of the kidneys are often necessary. In some cases, tissue must also be removed from the kidney (kidney biopsy).

Nutritional advice for renal insufficiency

Nutrition also plays an important role in chronic kidney disease. If necessary, your doctor will refer you to a dietician who will advise you in detail on a balanced and adapted diet. However, as nutrition in chronic kidney failure is a complex subject, you should not take advice from medical laypersons.

Preventing renal insufficiency

You should observe the following preventive measures

• Adjust blood glucose levels well in diabetes mellitus
• Adjust blood pressure values well
• Avoid being overweight
• do not smoke
• Use salt moderately
• Only take long-term painkillers after consulting your doctor; avoid non-steroidal anti-inflammatory drugs if you have risk factors for chronic renal insufficiency;

Renal insufficiency can be treated well with medication for a long time

Unfortunately, in the case of chronic damage, the kidney tissue does not have the ability to fully regenerate. However, if renal insufficiency is detected early, its progression can be slowed down or, ideally, even stopped. The cause of the kidney disease should be identified and treated appropriately. Good blood sugar and blood pressure control is important for diabetes mellitus and arterial hypertension. With a healthy lifestyle (healthy diet and regular exercise), you as a patient can do a lot for your body and your kidneys. There are also medications that can slow down or halt the progression of chronic kidney disease.

Another problem of chronic kidney disease is the increased risk of cardiovascular events such as heart attacks or strokes. Here too, measures must be taken to reduce the risk.

Renal replacement therapy or dialysis only in the last stage

In the early stages, chronic renal insufficiency can be treated well with medication. Only when the detoxification function is severely restricted does renal replacement therapy become necessary. This includes dialysis (blood washing) and kidney transplantation. Over 360 kidney transplants were performed in Switzerland in 2021, and we transplant between 80 and 100 kidneys every year at the University Hospital Zurich. On average, patients wait three years for a donor organ.