Acute kidney failure

"The first goal is to treat the disease or injury that has originally damaged your kidneys. Once it's under control, the focus will be on preventing excess fluids and wastes from building up in your blood, while your kidneys heal".


Acute renal failure is the sudden loss of the ability of the kidneys to remove excess fluid and electrolytes, as well as waste material from the blood.

It is more common in people who are already hospitalized, particularly those who need intensive care. In addition, it is often secondary to complicated surgery, a generalized infection, after a serious injury or when blood flow to the kidneys is disrupted.

Although usually reversible, the severity is variable and may require replacement treatment of kidney function for a period of time.

What are the symptoms of acute kidney failure?

It can be manifested by an alteration in the analysis, producing an increase in the levels of creatinine and urea, or by the appearance of certain symptoms such as a reduction in the volume of urine that can be accompanied by changes in appearance (dark, concentrated or bloody urine).

This reduction in volume can lead to the absence of urine or anuria. Due to this decrease in urine volume, if there is an uncontrolled entry of liquids, water retention occurs, leading to the appearance of edema or even cardiorespiratory overload that triggers.

Uremic syndrome: This is the main consequence of renal failure. It produces an accumulation of uremic toxins that produce alterations in various systems.

It is capable of provoking a gastritis with loss of appetite and disorders in the intestinal rhythm. It produces anemia caused by a decrease in the formation of red blood cells, as well as an increase in losses, even by some facility for bleeding.

A certain immunodeficiency is caused, which facilitates the appearance of infections. There are hormonal changes such as certain hypothyroidism.

The most common symptoms are:

  • Edemas.
  • Uremic syndrome.
  • Decrease in the amount of urine. Anuria.

Among the most affected systems is the neurological with development of a neuropathy and especially progressive metabolic encephalopathy with impaired cognitive ability that in severe cases leads to coma.

Of course, the appearance of all these symptoms will depend on the patient's basal state, age and nutritional status, as well as the presence of other organ failures.

Do you have any of these symptoms?

You may have acute kidney failure

What are the causes of acute kidney failure?

Acute renal failure may occur because some or all of the mechanisms involved in glomerular filtration fail.

A decrease in filtration may occur when the filtration pressure decreases due to a reduction in blood pressure or significant hypovolemia (absolute due to hemorrhage or dehydration, or relative due to poor distribution of vascular volume as occurs in septic conditions, ascites, intestinal occlusions).

Such acute renal failure may occur due to loss of functional units, as in glomerulonephritis, or due to the action of toxins such as some drugs (including intravenous contrast).

Other causes of acute renal failure are those that occur when there is an obstructive condition that does not allow the elimination of the filtrate, as occurs when there is a prostatic obstruction or by ureteral compression by masses or nodes.

What are the risk factors?

There are several factors that can predispose to the appearance of this disease, such as advanced age, chronic infection, diabetes, high blood pressure, immune disorders, kidney and liver problems, prostatic hypertrophy and bladder obstruction.

The signs and symptoms presented by these patients are

  • Decreased urine production.
  • Lack of elimination of waste products through urine.
  • Fluid retention, causing edema (swelling) in the legs, ankles or feet.
  • Sleepiness, breathing difficulty, fatigue, confusion and even coma in very serious cases and normally associated with other diseases.

How is acute kidney failure diagnosed?

Imagen de recogida de orina para análisis. Clínica Universidad de Navarra

Because acute kidney failure is often a complication of other serious diseases, sometimes signs and symptoms may go unnoticed or be attributed to the underlying disease.

When this condition is suspected, blood and urine tests should be performed. The alterations that can appear are: diminution of the volume of urine (less than 500 milliliters), increase in blood of the urea and creatinine and elevated electrolytes like the potassium.

It is usually necessary to perform an abdominal ultrasound and sometimes even a kidney biopsy to determine the cause of acute kidney failure.

The sooner it resolves, the more likely it is that kidney function will be restored. Sometimes, acute kidney failure causes permanent loss of kidney function and people require permanent dialysis or a kidney transplant to survive.

How is acute kidney failure treated?

Treatment begins by correcting the cause of the kidney failure. This can be clearly observed when there is dehydration or hypotension, restoring volume, or when there is an obstruction, in this case the use of a tube or nephrostomy is the solution.

When the kidneys have been significantly affected and there has been no recovery after stabilizing the patient, it is necessary to keep a watchful eye on the vital signs, control the balances to avoid overloading, use medications that must be adjusted with respect to the dose or suppression if they can have a negative influence

In certain cases, diuretics may be used if it is necessary to increase the rate of diuresis, or in some cases, start by replacing kidney function through the use of dialysis techniques.

Where do we treat it?


The Nephrology Service
of the Clínica Universidad de Navarra

The Nephrology Service of the Clínica Universidad de Navarra has more than five decades of experience, both in the diagnosis and treatment of all kidney pathologies and in the transplant of this organ. 

Our specialists have completed their training in centers of national and international reference.

We have the best facilities in the Dialysis Unit in order to offer the highest quality care to our patients.

Imagen de la fachada de consultas de la sede en Pamplona de la Clínica Universidad de Navarra

Why at the Clinica?

  • National reference in kidney transplantation, pioneer in living donor kidney transplantation.
  • Specialized nursing for the care and follow-up of our patients.
  • Cardiovascular and renal damage prevention program.