- Acute renal insufficiency
- Sudden renal failure
Definition of kidney failure
Acute renal failure (ANV) can have various causes, such as : It often occurs after serious injury, surgery, shock or sepsis (medical term for blood poisoning). It has a particularly bad prognosis in the context of multiple organ failure. In acute kidney failure, the function of the kidney is reduced to such an extent that it is no longer able to fulfil its tasks.
- Acute glomerulonephritides
- Damage to the blood vessels of the kidneys (e.g. vasculitis)
- Toxins and many more. There is a common classification according to the origin of the cause: Acute kidney failure requiring dialysis occurs with a frequency of about 30 patients /1 million inhabitants /year, whereas acute kidney failure not requiring dialysis occurs much more frequently. Especially as part of multi-organ failure (failure of several internal organs simultaneously), it is becoming increasingly common, especially in septic patients (=patients with blood poisoning) with systemic (=infection affecting the entire body) infection (Systemic Inflammatory Response Syndrome – SIRS).
Prerenal acute kidney failure is usually caused by a severe volume deficiency (e.g. bleeding/blood loss) or shock. Its occurrence as part of multi-organ failure should be particularly emphasized, often affecting septic patients (blood poisoning from bacterial seed). Other causes can be acute circulatory disorders, such as arterial embolism, venous thrombosis (blood clotting due to blood clotting), i.e. occlusive diseases of vessels or an aneurysm (circumscribed dilatation of an arterial blood vessel).
The symptoms depend on the respective cause. They can be gradual, so that acute kidney failure is not recognized at first. This leads to limited (oliguria) or even no longer existing urination (anuria) and the complications resulting from this, such as acidosis, hyperkalemia (increase in potassium in the blood) and many more.
The usability of the laboratory values can be limited by concomitant diseases of the liver, heart or kidney, as well as by the administration of diuretics (drugs to stimulate kidney function (urination)). Renal acute renal failure is caused by acute glomerular (rapid progressive glomerulonephritis) and interstitial (interstitial nephritis) diseases (see Kidney). It may also be caused by toxins or vasculitis (inflammation of blood vessels).
Particularly in the case of the latter diseases, a tissue sample of the kidney (kidney biopsy) should be taken as early as possible for diagnostic clarification. This group of causes also includes hemolytic uremic syndrome (HUS) and acute kidney transplant rejection. The symptoms here are varied and usually include signs of a general disease, such as: Postrenal acute renal failure is caused by obstruction of drainage in the efferent urinary tract.
The obstruction can be located inside the ureters or compress them from the outside (e.g. prostate changes; see prostate). This can lead to cramping (colicky) pain in the area of the urinary tract. The exact cause can usually be found out with an ultrasound examination.
The amount of urine excreted often cannot be used to make a diagnosis, as the leading symptom oliguria (low urine excretion), as mentioned above, may be absent. Metabolic diseases, such as the storage disease Fabry’s disease, also often lead to kidney failure if left untreated! – Fever
- Skin changes
- Joint Pain
- Or anemia.
- Prerenal acute renal failure
- Renal acute renal failure
- Postrenal acute renal failure
To describe the stages of renal insufficiency there are different classification systems. If the kidney function is acutely restricted, the AKIN stages are often used. AKIN stands for acute kidney injury.
A distinction is made here between stages 1-3. The stages are classified according to two parameters. The absolute urine excretion over a certain period of time and the increase in the creatinine value.
Creatinine is a protein that is produced in the body and excreted via the kidneys. An increase in creatinine value indicates reduced kidney function. Stage AKIN 1 is when the creatinine level rises by 1.5 to 2 times the normal value or by 0.3 mg/dl within 48 hours.
Alternatively, a stage 1 AKIN occurs when urine excretion is less than 0.5 ml per kilogram of body weight per hour over 6 hours. If a man weighing 70 kg excretes less than 35 ml per hour over 6 hours (i.e. less than 210 ml in 6 hours), this is called stage 1 AKIN. A stage 2 AKIN is present when creatinine levels are 2 to 3 times higher than normal or when urine excretion is less than 0.5 ml per kilogram of body weight over 12 hours.
In our example, this means a urine excretion of less than 420 ml in 12 hours. In case of an AKIN stage 3, there is a creatinine increase before which the norm is exceeded by more than 3 times or the creatinine value is above 4 mg/dl and there is an acute increase of >0.5 mg/dl. Alternatively, AKIN 3 has a urine excretion of less than 0.3 ml per kilogram body weight per hour over 24 hours (in our example less than 504 ml in 24 hours) or there is an anuria over 12 hours, i.e. no urine is excreted at all.
There are other classifications for the classification of renal insufficiency, for example those according to KDIGO and those according to the glomerular filtration rate (GFR). However, these two classifications deal with chronic, not acute, kidney failure. They are divided into 4 stages according to GFR and 5 stages according to KDIGO. The higher the stage, the more advanced the renal failure.