According to an article published by Dr. Debra Primovic:
Acute renal failure (ARF) is a life-threatening disorder that can affect dogs of any age.
Acute renal failure may be caused by decreased blood flow to the kidneys (called ischemia) or exposure to certain drugs or chemicals that are toxic to the kidneys.
Low blood flow to the kidneys may occur during anesthesia and surgery, and some drugs such as the non-steroidal anti-inflammatory agents like ibuprofen may also cause ARF by reducing blood flow to certain parts of the kidneys. Other causes of reduced blood flow to the kidneys include severe dehydration, shock, poor heart function, heat stroke and overwhelming infection (sepsis).
Many toxins can damage the kidneys and lead to ARF. Probably most important is ethylene glycol, which is the active ingredient of anti-freeze. Some antibiotics, especially a class of injectable antibiotics known as aminoglycosides, can cause damage to the tubules of the kidney and ARF. High blood calcium concentration likewise can damage the kidneys. Heavy metals (e.g. lead, arsenic), contrast dyes used for certain X-ray procedures, and some anesthetics also can damage the kidneys. An important toxin that specifically affects the kidneys of dogs is the Easter Lily. Dogs should never be allowed access to this group of plants. Some older drugs used to treat heartworms (thiacetarsamide) and fungal infections (amphotericin B) also are toxic to the kidneys.
Acute bacterial infection of the kidneys (called pyelonephritis) also can produce ARF.
Rare causes of ARF include glomerulonephritis (acute inflammation of the microscopic filtering devices of the kidney called glomeruli), glomerular amyloidosis (deposition of an insoluble type of protein in the kidney), disseminated intravascular coagulation (a body-wide clotting disorder), obstruction by blood clots of the arteries going to the kidneys, and hemolytic-uremic syndrome (liver and kidney failure caused by a specific strain of the bacteria E. coli).
Urinary obstruction is a type of reversible ARF that is treated by relieving the obstruction.
The most common causes of death during treatment of ARF are high blood potassium concentration, acid-base disturbances, very high concentrations of waste products in the blood that do not improve with fluid therapy and excessive administration of fluids with fluid accumulation in the lungs.
Animals unable to produce urine despite medical treatment have little chance for survival without peritoneal dialysis (infusion and removal of fluid into the abdominal cavity to remove waste products from the body). Hemodialysis can be performed in animals but is only available at selected referral hospitals and is very costly.
The prognosis for recovery of kidney function in ARF depends on the severity of the kidney damage, the underlying cause of ARF and supportive treatment.
Other medical problems can lead to symptoms similar to those encountered in ARF. A thorough medical evaluation is needed to diagnose ARF including laboratory testing and diagnostic imaging (X-rays or ultrasound). Warning signs that owners may see in pets with ARF include complete loss of appetite, marked lethargy, and vomiting. Unfortunately, these symptoms are very non-specific and may be caused by many other disease conditions. If is important to consult your veterinarian promptly.
Veterinary care should include diagnostic tests of kidney function, including blood tests and urinalysis, and subsequent treatment recommendations.
Diagnosis:
Diagnostic tests may be needed to recognize ARF and to exclude other diseases. Tests may include:
A complete medical history and physical examination
A complete blood count (CBC) to evaluate for signs of infection, inflammation, anemia or clotting abnormalities
Blood biochemistry tests to identify the presence of kidney failure. Commonly used tests to identify kidney failure include blood urea nitrogen (BUN), serum creatinine, and serum phosphorus. These test results are abnormally high in patients with kidney failure but these tests alone do not identify whether the kidney failure is acute or chronic. The veterinarian must use other tests and diagnostic reasoning to determine if the kidney failure is acute or chronic.
Urinalysis. Protein, blood or glucose may be observed in the urine of patients with ARF. The presence of microscopic crystals (such as calcium oxalate) can support a diagnosis of ethylene glycol (anti-freeze) poisoning. Microscopic casts of the kidney tubules often are seen with acute injury of the kidney, and white blood cells or casts may be found when kidney infection is present.
Additional diagnostic tests may be recommended for individual pets, including:
Kidney ultrasonography to determine if the kidney failure is acute or chronic and to help identify some specific causes of ARF (e.g. anti-freeze poisoning). Kidneys of patients with ARF typically are normal-sized to large. The presence of small, irregularly-shaped kidneys more often suggests a chronic kidney disease. Dogs that drink anti-freeze often have kidneys that have increased density on ultrasound within a few hours of consuming anti-freeze.
A urine culture to identify urinary tract infection
Blood gas analysis to identify acid-base disturbances
Arterial blood pressure should be monitored because high blood pressure can complicate ARF. Central venous pressure may be monitored with a catheter in the jugular vein, especially if an inadequate volume of urine is produced.
Ethylene glycol testing to diagnose this toxicity; a special test kit is required for this purpose.
Kidney biopsy may be necessary to determine the cause of ARF and to guide treatment and prognosis.
Therapy:
Treatments for ARF may include one or more of the following:
Treatment of ARF must be individualized based on the cause and severity of the condition, as well as other conditions and complications identified by your veterinarian. Of great importance is the ability of the pet to produce urine. Low urine output or complete absence of urine production is a very serious finding.
Prognostic signs are poor if the pet does not respond to initial drug and fluid therapy. The ultimate goal of ARF management is to provide supportive care while allowing the kidneys time to recover. Your veterinarian should identify and correct the most life-threatening body chemistry problems while searching for the cause of ARF. Drugs that may be contributing to ARF should be discontinued. Dehydration is corrected by intravenous administration of fluids.
Vomiting may be induced if a kidney toxic agent has been ingested within the past few hours and the dog has not yet vomited. This is especially important in anti-freeze poisoning in which time is critical. Always call your veterinarian immediately if you believe your pet has consumed even the smallest quantity of anti-freeze.
Fluid therapy is important to increase kidney blood flow, correct and prevent dehydration and control abnormalities in serum electrolytes. Care must be taken to avoid overhydration, because the kidneys may not be able to produce sufficient urine to eliminate excess fluid. Overhydration can lead to fluid accumulation in the lungs (pulmonary edema) which may be life-threatening. Nevertheless, fluid therapy is extremely important initially, and drug therapy may be required to encourage urine production.
Fluid therapy may aid kidney function and encourage urine production. Diuretics may be used after rehydration. Mannitol and furosemide are diuretic agents that may be given, often in combination with dopamine. Dopamine is a chemical that causes dilation of the renal arteries and potentially can increase filtration in the kidneys when administered at low dosages.
Management of hyperkalemia (high blood potassium concentration) is important because potassium is toxic to the heart. Treatment may include sodium bicarbonate, glucose and insulin, calcium, or dialysis. An electrocardiogram should be monitored during treatment.
Acid base imbalance is corrected by administration of sodium bicarbonate.
Abnormally high blood phosphorus concentration may be treated with intestinal phosphorus binders such as aluminum hydroxide.
Dogs with ARF may vomit frequently and several different drugs may be used to control this symptom.
Anemia due to blood loss can be treated with blood transfusion.
Ethylene glycol poisoning may be treated with 4-methylpyrazole (Antizol) or 20 percent ethanol.
Close patient monitoring is vital. Monitoring may include serial body weight (to facilitate proper fluid therapy), measurement of urine output (often with a urinary catheter), packed cell volume (an indication of the percentage of the blood that consists of red blood cells), and total plasma proteins to monitor fluid volume. Serial determination of serum biochemistry tests is necessary to determine if the animal is responding to treatment.
Treatment for ARF may require several days or as long as two to three weeks depending on the underlying cause of ARF and the response of the individual animal to treatment. This prolonged hospitalization can be frustrating for all concerned, because it frequently is impossible to predict the outcome. If conservative medical treatment fails, peritoneal dialysis (or in exceptional circumstances hemodialysis) may be a treatment possibility. Referral to a specialist or 24-hour critical care facility is required for dialysis treatment.
Euthanasia must be considered for pets that do not respond to treatment.
To read Dr. Primovic's complete article go to:
http://www.petplace.com/articles/artShow.asp?artID=86
I hope you find this information helpful.
Regards,
Scott
