Signs and symptoms of acute kidney failure may include:

• Decreased urine output, although occasionally urine output remains normal
• Fluid retention, causing swelling in your legs, ankles or feet
• Shortness of breath
• Fatigue
• Confusion
• Nausea
• Weakness
• Irregular heartbeat
• Chest pain or pressure
• Seizures or coma in severe cases

Sometimes acute kidney failure causes no signs or symptoms and is detected through lab tests done for another reason.

Acute kidney failure can occur when:

• You have a condition that slows blood flow to your kidneys
• You experience direct damage to your kidneys
• Your kidneys' urine drainage tubes (ureters) become blocked and wastes can't leave your body through your urine

Impaired blood flow to the kidneys

Diseases and conditions that may slow blood flow to the kidneys and lead to kidney injury include:

• Blood or fluid loss
• Blood pressure medications
• Heart attack
• Heart disease
• Infection
• Liver failure
• Use of aspirin, ibuprofen (Advil, Motrin IB, others), naproxen sodium (Aleve, others) or related drugs
• Severe allergic reaction (anaphylaxis)
• Severe burns
• Severe dehydration

Damage to the kidneys

These diseases, conditions and agents may damage the kidneys and lead to acute kidney failure:

• Blood clots in the veins and arteries in and around the kidneys
• Cholesterol deposits that block blood flow in the kidneys
• Glomerulonephritis (gloe-mer-u-loe-nuh-FRY-tis), inflammation of the tiny filters in the kidneys (glomeruli)
• Hemolytic uremic syndrome, a condition that results from premature destruction of red blood cells
• Infection
• Lupus, an immune system disorder causing glomerulonephritis
• Medications, such as certain chemotherapy drugs, antibiotics and dyes used during imaging tests
• Scleroderma, a group of rare diseases affecting the skin and connective tissues
• Thrombotic thrombocytopenic purpura, a rare blood disorder
• Toxins, such as alcohol, heavy metals and cocaine
• Muscle tissue breakdown (rhabdomyolysis) that leads to kidney damage caused by toxins from muscle tissue destruction
• Breakdown of tumor cells (tumor lysis syndrome), which leads to the release of toxins that can cause kidney injury

Urine blockage in the kidneys

Diseases and conditions that block the passage of urine out of the body (urinary obstructions) and can lead to acute kidney injury include:

• Bladder cancer
• Blood clots in the urinary tract
• Cervical cancer
• Colon cancer
• Enlarged prostate
• Kidney stones
• Nerve damage involving the nerves that control the bladder
• Prostate cancer

Acute kidney failure almost always occurs in connection with another medical condition or event. Conditions that can increase your risk of acute kidney failure include:

• Being hospitalized, especially for a serious condition that requires intensive care
• Advanced age
• Blockages in the blood vessels in your arms or legs (peripheral artery disease)
• Diabetes
• High blood pressure
• Heart failure
• Kidney diseases
• Liver diseases
• Certain cancers and their treatments

Potential complications of acute kidney failure include:

• Fluid buildup. Acute kidney failure may lead to a buildup of fluid in your lungs, which can cause shortness of breath.
• Chest pain. If the lining that covers your heart (pericardium) becomes inflamed, you may experience chest pain.
• Muscle weakness. When your body's fluids and electrolytes — your body's blood chemistry — are out of balance, muscle weakness can result.
• Permanent kidney damage. Occasionally, acute kidney failure causes permanent loss of kidney function, or end-stage renal disease. People with end-stage renal disease require either permanent dialysis — a mechanical filtration process used to remove toxins and wastes from the body — or a kidney transplant to survive.
• Death. Acute kidney failure can lead to loss of kidney function and, ultimately, death.