Alternate Names: Renal failure - acute; Kidney failure; Kidney failure - acute; Renal failure; Acute kidney failure; ARF
Causes and Risks: The kidneys filter wastes and excrete fluid when the pressure of blood in the bloodstream forces blood through the internal structures of the kidney.
Decreased blood flow is one cause of damage to the kidney. It may occur when there is extremely low blood pressure from trauma, complicated surgery, septic shock, hemorrhage, burns and associated dehydration, or other severe or complicated illness.
Acute tubular necrosis (ATN) is another cause of acute renal failure. ATN may be caused by ischemia (decreased oxygenation of the tissues) from obstruction or stricture of the renal artery (see acute arterial occlusion of the kidney, renal artery stenosis). It may also occur following toxic injury to the kidney after exposure to metals, solvents, radiographic contrast, certain antibiotics and other medications, and other substances that are toxic to the kidney.
Myoglobinuria (myoglobin in the urine) may cause acute renal failure. This condition may be caused by rhabdomyolysis, alcohol abuse (see alcoholism), a crush injury, necrosis (tissue death) of muscles from any cause, seizures, and other causes.
Acute renal failure may follow direct injury to the kidney. It may also follow infections such as acute pyelonephritis or septicemia. It may be a consequence of urinary tract obstruction such as a narrowing of the urinary tract (stricture), tumor, kidney stones, nephrocalcinosis, or enlarged prostate with subsequent acute bilateral obstructive uropathy. Severe acute nephritic syndrome can cause acute renal failure.
Other causes include disorders of the blood, such as idiopathic thrombocytopenic purpura (ITP), transfusion reaction, or other hemolytic disorders. Causes also include malignant hypertension and disorders associated with childbirth such as postpartum renal failure and bleeding associated with placenta abruptio or placenta previa. Autoimmune disorders such as scleroderma may cause acute renal failure.
Hemolytic uremic syndrome is one of the most frequent causes of acute renal failure in young children and appears to be increasing in prevalence. It is associated with the rapid onset of renal failure and other systemic manifestation. A toxin secreting bacterium, Eschereshia coli, found in contaminated undercooked meats, has been implicated as the cause of hemolytic uremic syndrome.
Acute renal failure affects approximately 3 out of 10,000 people admitted to the hospital. The urine produced usually decreases in volume, and there may be no urine produced. This causes fluids and waste products to accumulate in the body. Lab tests show an accumulation of nitrogen wastes such as creatinine and urea in the body (azotemia). These waste products act as poisons when they accumulate in the body, damaging tissues and the functioning of many different organs. If the wastes are not removed from the body, death eventually results.
Prevention: Treatment of causative disorders may help to prevent acute renal failure. Many cases may not be preventable.
Symptoms:
- decreased urine output (There may be none.)
- urination, excessive at night (can occur in some types of renal failure)
- ankle, feet, and leg swelling
- generalized swelling, fluid retention
- decrease in sensation, especially the hands or feet
- changes in mental status or mood
- slow, sluggish, lethargic movement
- seizures
- hand tremor
- nausea, vomiting
- prolonged bleeding, bruising easily
- growth, slow (child 0-5 years)
- flank pain
- fatigue
- ear noise/buzzing
- breath odor
- breast development in males
- blood pressure, high
Signs and Tests: Examination and testing may reveal acute renal failure rather than other disorders that affect kidney function. There is generalized edema (swelling) from fluid retention. Auscultation of the heart may show a murmur or other abnormal sounds caused by increased fluids. Auscultation of the lungs may show crackles.
Lab values may change suddenly (within a few days to 2 weeks):
This disease may also alter the results of the following tests:
Treatment: The goal of treatment of acute renal failure includes identifying and treating any reversible causes of the kidney failure (e.g., use of nephrotoxic medications, obstructive uropathy, volume depletion...). Additionally, treatment focuses on preventing the excess accumulation of fluids and wastes, while allowing the kidneys to heal. The kidneys may gradually resume function. Hospitalization is required for treatment and monitoring.
Fluid intake may be severely restricted to an amount equal to the volume of urine produced. Salt intake is usually also curtailed. Dietary intake of substances that are normally excreted by the kidney may be restricted to minimize their build up in the body. Specific dietary modifications will include following a diet plan that is high in carbohydrates, low in protein, sodium, and potassium intake.
Antibiotics may be used to treat or prevent infection. Diuretics may be tried in an attempt to increase the excretion of fluid from the kidney. Medications may be given to control hyperkalemia (increased blood potassium levels).
A major priority in treatment is to control dangerous hyperkalemia (increased blood potassium levels). A variety of different medications may be utilized to reduce blood potassium including IV (intravenous) calcium, glucose/insulin, and oral or rectal administration of potassium exchange resin (Kayexalate).
Dialysis may be used to remove excess waste and fluids. This often makes the person feel better and may make the kidney failure easier to control. Dialysis may not be necessary for all people, but is frequently lifesaving, particularly if serum potassium is dangerously high. Decreased mental status, pericarditis, increased potassium levels, total lack of urine production, fluid overload, and uncontrolled accumulation of nitrogen waste products (serum creatinine > 10 mg/dl and BUN > 120 mg/dl) are common indications for dialysis.
SUPPORT GROUP:
The stress of illness can often be helped by joining support groups where members share common experiences and problems. See kidney disease - support group.
Prognosis: Although acute renal failure is potentially life threatening and may require intensive treatment for a time, it usually reverses within several weeks to a few months after the underlying cause has been treated.
A few people will progress to chronic renal failure and/or end-stage renal disease. Death is most common when the cause of the kidney failure is related to surgery or trauma, or when it occurs in people with coexisting heart disease, lung disease, or recent stroke. Old age, infection, loss of blood from the GI (gastrointestinal) tract, and progression of the kidney failure also increase the risk of death.
Complications:
Call your health care provider if decreased urine output or other symptoms indicate acute renal failure may be present.
