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Acute Renal (Kidney) Failure

The kidneys have multiple important functions in the body. The primary functions of the kidneys are to remove toxic and waste products from the blood, maintain water and electrolyte balance, and produce a variety of hormones. In acute kidney failure, the problem develops over a short period of time, such as several days or even hours.

There is a wide variety of causes of kidney failure. Toxins, such as lilies in cats, raisins or grape ingestion in dogs, anti-freeze, and certain drugs (including over-the-counter human medications such as ibuprofen) can cause acute kidney failure. Severe infections of the kidney caused by bacteria such as Leptospirosis, as well as severe dehydration from other systemic disease can all cause kidney failure. Examples of these systemic diseases include extreme vomiting, diarrhea, heatstroke, sepsis, and hypercoagulable states that lead to clot formation. Although a severe disease process, acute renal failure can be reversed in certain cases.

Symptoms of acute kidney failure can include the following:

  • increased thirst and increased urination (in the early stages of the disease)
  • vomiting
  • anorexia
  • lethargy
  • oral ulceration

In later stages of the disease process animals can stop making urine which can lead to a life-threatening state.

The kidneys can be evaluated through multiple diagnostics tests. Routine blood work such a complete blood count and chemistry profile can be performed to check white and red blood cell counts, to look for elevated kidney values (BUN and Creatinine), elevated phosphorus levels, or altered electrolytes. Other tests such as x-rays and ultrasound can be used to look for structural changes in the kidneys as well as stones or areas with loss of blood supply. In some cases, a kidney biopsy may be considered. The urine should also be assessed in conjunction with blood work through a urinalysis which looks for crystals, bacteria, and concentration. If there is any concern for infection, a urine culture should also be performed.

Treatment of acute kidney failure usually includes intravenous fluid therapy. By hydrating the body and diluting out the toxins, we hope to give the kidneys time to recover. Antibiotic therapy may also be instituted if there are clinical signs of infection. Sometimes drugs such as furosemide (Lasix) or mannitol are given to help increase urine production and output. Patients are commonly put on gastrointestinal protectants such a Pepcid or Prilosec to avoid GI ulceration. If the patient refuses to eat, a feeding tube may be considered. In extreme cases dialysis can be instituted to help filter out acute toxins. Our hospital does not offer dialysis but transfer to another hospital (Animal Medical Center in New York City, for example) can be arranged.

Acute kidney failure can be a dynamic disease process. It is important to monitor for signs of GI ulceration, systemic hypertension and to monitor the electrolyte levels. GI ulceration can lead to decreased appetite, vomiting, weight loss, and in extreme cases perforation of ulcers or acute blood loss. Systemic hypertension if left untreated can cause permanent damage to the retinas in the eyes and affect vision as well as leave permanent damage to the kidneys. Electrolytes changes such as high levels of potassium, often associated with acute kidney failure, can lead to life threatening changes to the heart. Patients with acute kidney failure should be monitored 24 hours a day to give the proper medical response to these many changes.

The prognosis of acute kidney failure is poor to guarded. Response to therapy is key to gauging how your pet will do. If your pet has decreased urine production this lends a more guarded prognosis. It is also possible that your pet may recover but have permanent kidney damage and need chronic care such as a special diet or subcutaneous fluids. Acute kidney failure is a life threatening condition that needs immediate aggressive management to give your pet a chance at recovery.