Acute Kidney Failure: Causes, Symptoms & Treatment

Acute Kidney Failure: Causes, Symptoms & Treatment

There is a sudden loss of kidney function in acute kidney failure, also known as acute kidney failure or acute kidney injury. If no treatment is initiated, acute renal failure is life-threatening. What are the causes, the symptoms, and the different stages of kidney failure? You can read that and more here.

 

What is acute kidney failure?

Usually, it is the job of the kidneys to excrete excess minerals, metabolic end products and toxic substances through the urine. This keeps the body’s fluid and acid-base balance in balance.

One speaks of acute kidney failure (ANF) when this filter function of the kidneys deteriorates so severely within a few hours or days that toxins quickly accumulate in the body. Since less urine is excreted, there is also an accumulation of water (oedema) in the body, especially in the legs, and more rarely in the lungs. This situation can be life-threatening for the person concerned.

In contrast, in chronic renal failure, kidney function gradually deteriorates over some time. The kidney damage is irreversible, whereas the kidney tissue in acute kidney failure can recover after successful therapy. For more information on Chronic Kidney Failure, click here.

 

Causes: how does acute kidney failure develop?

In the case of acute kidney failure, the causes are divided into “prerenal” (in front of the kidneys, e.g. blood loss as a trigger), “intrarenal” (in the kidneys, e.g. poisoning) and “postrenal” (behind the kidneys due to blockage of the urinary tract, e.g. in the case of a urinary stone). ) divided.

Prerenal Causes

Acute kidney failure is usually the result of a sudden lack of blood flow to the kidneys. This can be caused by sudden blood loss, such as after a severe accident, by complications from heart or lung surgery, or by a sudden drop in blood pressure, as in the case of shock.

Severe dehydration or severe burns can also trigger acute kidney failure.

 

Intrarenal Causes

A frequent cause is poisoning, which damages the kidney tissue (such as bacterial toxins in infections, such as sepsis ) or allergic damage to the kidney corpuscles. Poisoning is usually caused by cytostatics, aminoglycoside antibiotics, non-steroidal anti-inflammatory drugs (NSAIDs) or X-ray contrast media.

Diseases that damage the blood vessels of the kidneys, such as severe high blood pressure, can also cause acute renal failure. In rare cases, it can also be caused by inflammation of the kidney tissue (glomerulonephritis).

Postrenal Causes

Ein weiterer möglicher Auslöser für die Nierenschädigung ist ein gestörter Abfluss des Urins aus den Nieren, beispielsweise verursacht durch Harnsteine, Tumore oder einen verstopften Urinkatheter.

Akutes Nierenversagen: Symptome

Zunächst stehen bei dem akuten Nierenversagen meist die Symptome der Grunderkrankung, beispielsweise der schweren Entzündung oder des Bluthochdrucks, im Vordergrund.

Danach kann es durch die Schädigung der Nierenfunktion zu weiteren Symptomen kommen. Mögliche Anzeichen sind unter anderem:

  • Verminderung der Harnproduktion auf weniger als 500 Milliliter pro Tag (Oligurie)
  • fast vollständiges Ausbleiben der Harnproduktion mit weniger als 100 Milliliter pro Tag (Anurie)
  • starke Nierenschmerzen, die als Flanken- oder Rückenschmerzen wahrgenommen werden
  • Müdigkeit
  • Übelkeit
  • Herzrhythmusstörungen
  • Vertiefung der Atmung
  • geschwollene Beine oder Atemnot durch Flüssigkeitsansammlungen
  • Juckreiz
  • Fieber
  • starkes Durstgefühl
  • niedriger Blutdruck

Unbehandelt kann akutes Nierenversagen zu einem starken Anstieg des Kaliumspiegels (Hyperkaliämie) im Blut führen. Überschüsse dieses Mineralstoffes werden normalweise über die Nieren ausgeschieden. Eine Hyperkaliämie kann im schlimmsten Fall zum Herzstillstand und einer Übersäuerung des Blutes (Azidose) führen, welche ein Koma zur Folge haben kann.

 

Diagnose: Laborwerte geben Aufschluss

Die körperlichen Anzeichen bei akutem Nierenversagen sind (mit Ausnahme der Harnproduktion) zunächst eher unspezifisch. Aus diesem Grund werden bei Patient*innen neben der Anamnese insbesondere Blut- und Urinproben zur Diagnose herangezogen. So werden die Kreatinin- und Harnstoffwerte überprüft. Im Urin werden Eiweißwerte sowie Harnsedimente bestimmt.

Je nach vermuteter Ursache können auch eine Ultraschalluntersuchung der Nieren und der Harnwege sowie eine Gewebeprobe aus der Niere vorgenommen werden.

Stadien des akuten Nierenversagens

Die akute Niereninsuffizienz wird zunächst in eine Form mit Oligurie (verminderter Harnproduktion) und eine Form ohne Oligurie unterteilt.

Darüber hinaus unterscheidet man drei Stadien, die anhand der Parameter der sogenannten RIFLE- und AKIN-Kriterien bestimmt werden.

Stadium 1

The creatinine measured in the blood serum has increased by at least 0.3 milligrams per deciliter of blood serum in the last 48 hours, or there has been a 1.5 to 1.9-fold increase in the creatinine value compared to the baseline value.

The urine excreted within six to twelve hours was less than 0.5 millilitres per kilogram of body weight.

 

Stadium 2

Serum creatinine increased by 2 to 2.9 times the baseline value.

The amount of urine excreted in the last six to twelve hours was 0.3 millilitres per kilogram of body weight.

Stadium 3

The measured creatinine level in the blood increased by over three times the baseline value or to at least 4 milligrams per deciliter of blood serum.

The amount of urine was less than 0.3 millilitres per kilogram of body weight for 24 hours.

Treatment for acute renal failure

If treated in time, acute kidney failure can often be cured entirely – however, if treatment is started too late, kidney failure can be fatal. Treatment depends on the type and stage of the disease. Acute kidney failure is an emergency, which is why emergency services should always be called if the disease is suspected.

The underlying disease is treated in the hospital – for example, kidney stones or infections are removed. The circulation must also be stabilized. If there is a loss of blood or fluid, this is compensated. Urine excretion and volume status (in the case of overhydration) are monitored.

In addition, symptomatic therapy is carried out with medications such as dopamine and the hormone ANP to improve blood flow to the kidneys and promote the excretion of urine via the kidneys. From stage 2 onwards, temporary dialysis (renal replacement therapy) is often required. The international KDIGO recommendations (“Kidney Disease – Improving Global Outcomes”) guide treating doctors.

 

Prognosis: How often does death occur?

The prognosis is usually only good once the disease that caused the condition has been overcome, as the tissue changes usually regress after acute renal failure. If the cause cannot be controlled, however, the mortality rate is very high, mainly if there are severe pre-existing conditions or other organs have been damaged. It is estimated that one in two people treated for acute renal failure dies. However, the actual cause of death is often the underlying disease that led to the renal failure.

In general, the prognosis is better if no oliguria has occurred. In some cases, permanent impairment of kidney function in the form of chronic kidney failure can be the result of acute kidney failure.

 

 

Similar Posts

Leave a Reply

Your email address will not be published. Required fields are marked *