Acute (sudden) kidney failure is the sudden loss of the ability of the kidneys to remove waste and concentrate urine without losing electrolytes.

There are many possible causes of kidney damage. They include:

• Decreased blood flow, which may occur with extremely low blood pressure caused by trauma, surgery, serious illnesses, septic shock, hemorrhage, burns, or dehydration
• Acute tubular necrosis (ATN)
• Infections that directly injury the kidney such as acute pyelonephritis or septicemia
• Urinary tract obstruction (obstructive uropathy)
• Autoimmune kidney disease such as interstitial nephritis or acute nephritic syndrome
• Disorders that cause clotting within the thin blood vessels of the kidney
  • Idiopathic thrombocytopenic thrombotic purpura (ITTP)
  • Transfusion reaction
  • Malignant hypertension
  • Scleroderma,
  • Hemolytic-uremic syndrome
  • Disorders of childbirth, such as bleeding placenta abruptio or placenta previa

• Decrease in amount of urine (oliguria)
• Urination stops (anuria)
• Excessive urination at night
• Ankle, feet, and leg swelling
• Generalized swelling, fluid retention
• Decreased sensation, especially in the hands or feet
• Decreased appetite
• Metallic taste in mouth
• Persistent hiccups
• Changes in mental status or mood
  • Agitation
  • Drowsiness
  • Lethargy
  • Delirium or confusion
  • Coma
  • Mood changes
  • Trouble paying attention
  • Hallucinations
• Slow, sluggish, movements
• Seizures
• Hand tremor (shaking)
• Nausea or vomiting, may last for days
• Brusing easily
• Prolonged bleeding
• Nosebleeds
• Bloody stools
• Flank pain (between the ribs and hips)
• Fatigue
• Breath odor
• High blood pressure

Examination and testing can help diagnose acute kidney failure and help rule out other problems that can affect kidney function.

Many patients have generalized swelling caused by fluid retention. The doctor will use a stethoscope to listen to the heart and lungs. A heart murmur, crackles in the lungs, inflammation of the lining of the heart (pericarditis), or other related to extra fluid may be heard.

The results of laboratory tests may change suddenly (within a few days to 2 weeks).

• Urine tests (urinalysis) may be abnormal.
• Serum creatinine, BUN, creatinine clearance, and serum potassium levels may increase.
• Arterial blood gas and blood chemistries may show metabolic acidosis.
• Kidney or abdominal ultrasound are preferred tests, but abdominal x-ray, abdominal CT scan, or abdominal MRI can tell if there is a blockage in the urinary tract.
• Blood tests may help reveal the underlying cause of kidney failure.