Acute Kidney Failure: Causes, Symptoms, and Treatment

Acute kidney failure, also called acute kidney injury, is a serious medical condition that happens when the kidneys suddenly stop working properly. This can develop within a few hours or a few days. In most cases, it develops within 48 hours, but sometimes it can take up to 7 days.

When acute kidney failure occurs, your kidneys cannot remove waste, toxins, and extra fluids from your blood the way they should. As a result, harmful substances begin to build up in the body. If not treated quickly, it can become life-threatening. Fortunately, in many cases, acute kidney failure can be reversed if treated early.

Therefore, understanding the causes, acute kidney failure symptoms, and treatment options can help you recognize the condition early and seek medical care on time.

What Is Acute Kidney Failure?

Acute kidney failure is the rapid loss of kidney function, usually in less than two days. It may be mild at first, but it can quickly become severe if not managed properly.

The condition ranges from temporary and reversible kidney injury to severe kidney damage that may require dialysis. Many people in otherwise good health can recover most or all of their kidney function with proper treatment.

What Do the Kidneys Do?

The kidneys are two bean-shaped organs located under the ribcage toward the back. Each kidney is about the size of a fist. Although most people have two kidneys, a healthy life is possible with just one functioning kidney.

The kidneys perform several important functions. For example:

• Filter waste and toxins from the blood
• Remove extra fluid through urine
• Maintain a balance of electrolytes such as sodium and potassium
• Help control blood pressure
• Support red blood cell production

When kidney function declines, waste products stay in the body. Over time, this can lead to kidney injury, serious kidney damage, and problems affecting the heart, brain, and lungs.

Acute Kidney Failure Symptoms

The signs of acute kidney failure can vary depending on the cause and severity. In some cases, people may not notice symptoms in the early stages. In other cases, symptoms appear suddenly and progress quickly.

Common acute kidney failure symptoms include:

• Making less urine than usual (oliguria) or no urine at all (anuria)
• Swelling in the legs, ankles, or feet
• Shortness of breath
• Fatigue or extreme tiredness
• Confusion or mood changes
• High blood pressure
• Nausea or vomiting
• Decreased appetite
• Flank pain, which is pain between the ribs and the hips
• Chest pain or pressure
• Seizures or coma in severe cases

Recognizing the early signs of acute kidney failure is very important as it can help prevent further kidney damage and improve recovery outcomes.

Causes of Acute Kidney Failure

Acute kidney injury usually happens for one of three main reasons:

• Reduced blood flow to the kidneys
• Direct damage to the kidneys
• Blockage in the urinary tract

1. Reduced Blood Flow to the Kidneys

When blood flow to the kidneys decreases, they cannot filter waste effectively. As a result, kidney injury may develop.

Common causes include:

• Severe dehydration
• Blood loss
• Very low blood pressure
• Heart attack or heart failure
• Severe infection or sepsis
• Liver failure
• Severe burns
• Allergic reactions

In addition, certain medicines such as ibuprofen, naproxen, and some blood pressure drugs can reduce blood flow to the kidneys.

2. Direct Kidney Damage

Sometimes the kidneys themselves are injured and thus develop kidney failure. Causes may include:

• Inflammation of the kidney filters, known as glomerulonephritis
• Severe infections, including COVID-19
• Certain chemotherapy drugs or antibiotics
• Exposure to toxins like heavy metals or cocaine
• Autoimmune diseases such as lupus
• Blood clots in the kidney vessels
• Rhabdomyolysis, which is the breakdown of muscle tissue
• Tumor lysis syndrome, which releases toxins into the blood

3. Urinary Blockage

Another important cause is urinary blockage. When urine cannot leave the body, pressure builds up and damages the kidneys.

This may occur due to:

• Kidney stones
• Enlarged prostate
• Blood clots in the urinary tract
• Bladder cancer
• Prostate cancer
• Cervical cancer
• Colon cancer
• Tumors pressing on the ureters

In some cases, kidney injury may occur alongside serious conditions like kidney cancer, which affects kidney tissue directly.

Risk Factors

Certain groups are more likely to develop acute kidney failure. For example, higher risk is seen in:

• Older adults
• People already living with chronic kidney disease (CKD)
• Patients admitted to intensive care units
• People with diabetes
• Individuals with high blood pressure
• Patients with heart or liver disease
• People receiving certain cancer treatments

Although it is more common in adults, children can also develop kidney injury, especially during severe infections or cancer treatments.

Stages of Acute Kidney Injury

Doctors divide acute kidney failure into three stages based on blood creatinine levels and urine output. This staging system helps determine severity and guide treatment decisions.

Stage 1: Mild Kidney Injury

• Creatinine rises 1.5 to 1.9 times baseline
• Urine output less than 0.5 mL per kg per hour for 6 to 12 hours

At this stage, kidney function has started to decline. Early treatment can often reverse the damage.

Stage 2: Moderate Kidney Injury

• Creatinine rises 2 to 2.9 times baseline
• Low urine output for 12 hours or more

Close monitoring and prompt treatment are required.

Stage 3: Severe Kidney Injury

• Creatinine rises three times baseline or reaches 4.0 mg per dL or higher
• Dialysis may be required
• Very low urine output for 24 hours or no urine for 12 hours

This stage is serious and needs urgent medical attention.

Diagnosis of Acute Kidney Failure

If a doctor suspects acute kidney failure, they will perform a full evaluation. This includes reviewing recent illnesses, medications, fluid intake, and symptoms.

Common tests include:

• Serum creatinine blood test
• Estimated glomerular filtration rate
• Blood urea nitrogen test
• Electrolyte tests
• Urinalysis
• Ultrasound imaging
• Kidney biopsy in rare cases

Acute Kidney Failure Treatment

Acute kidney failure treatment depends on the underlying cause. Therefore, the main goal is to correct the problem and allow the kidneys to recover.

Common treatment approaches include:

• Stopping medicines that may be harming the kidneys
• Giving intravenous fluids for dehydration
• Treating infections with antibiotics
• Inserting a urinary catheter to relieve urinary blockage
• Managing electrolyte imbalance
• Dialysis in severe cases

In many situations, dialysis is temporary until kidney function improves. Meanwhile, most patients require hospitalization for monitoring and supportive care.

Complications

If not treated promptly, acute kidney failure can lead to:

• Fluid buildup in the lungs
• Chest pain from inflammation around the heart
• Muscle weakness from electrolyte imbalance
• Permanent kidney damage
• End-stage renal disease
• Death in severe cases

Therefore, early treatment greatly reduces these risks.

Acute Kidney Failure and Cancer

Kidney injury can sometimes be linked to cancer or cancer treatments. For example, patients with clear cell renal cell carcinoma may experience kidney damage due to the disease or treatment.

Similarly, children diagnosed with Wilms tumor, a type of pediatric kidney cancer, may also develop kidney complications during therapy.

In such cases, participation in renal cell carcinoma clinical trials may provide access to advanced therapies. Additionally, broader clinical trials for oncology offer patients opportunities to explore potential new treatment options under expert medical supervision.

Prognosis of Acute Kidney Failure

The prognosis of acute kidney failure depends on the cause, severity, and how quickly treatment begins.

Generally, many patients recover fully, especially when the condition is diagnosed early. However, in severe cases, particularly in older adults or critically ill patients, long-term kidney damage may occur.

Some patients may need temporary dialysis, and a small percentage may later develop chronic kidney disease. Therefore, regular follow-up care remains very important.

Conclusion

Acute kidney failure is a serious but often treatable condition that develops quickly and can become life-threatening if ignored. By recognizing the signs of acute kidney failure early and seeking medical care promptly, patients can significantly improve their chances of recovery.

With early diagnosis, proper treatment, and regular follow-up, many patients recover well and regain normal or near-normal kidney function. Furthermore, understanding personal risk factors and maintaining ongoing medical care can reduce the chances of future kidney injury or long-term kidney damage.

In more complex cases, especially those linked to cancer or other serious conditions, participation in clinical research studies in Nebraska may offer access to advanced therapies and expert care.