Acute Renal (Kidney) Failure in Dogs

Acute renal failure, also called acute kidney injury (AKI), will often cause vague symptoms of illness in your dog, due to his kidneys being unable to meet his body’s excretory and metabolizing needs. For many, this leads to a trip to the veterinarian for an exam. A sudden increase in creatinine and blood urea nitrogen (BUN) to above normal levels point to acute renal failure.

Acute renal failure occurs when your dog’s kidneys are unable to meet his body’s needs, typically occurring due to toxic chemicals ingested or built up in your dog’s system as a result of an underlying condition.

When your dog is suffering from acute renal failure, you may notice a variety of symptoms to include: 

• Lethargy
• Vomiting 
• Diarrhea 
• A decrease in appetite
• Depression
• Sores in the mouth
• Large amounts of urination followed by less urination than usual

Types 

Your veterinarian will want to confirm whether the kidney disease experienced by your dog is acute or chronic in order to decide how to proceed in regards to treatment.

In chronic kidney disease, typically much of the regenerative process of the kidneys has taken place prior to the initial diagnosis and kidneys often appear small. With acute kidney disease, at the time of diagnosis there is usually quite a bit of improvement in kidney function that can be made (assuming the dog can get through the acute episode) and the kidneys will appear normal to enlarged.

The cause of acute renal failure is sudden, major damage to your dog’s kidneys. Typically, the damage is due to toxic chemicals (consumed by your dog or through build up as a result of something in your dog’s body not functioning correctly). Toxins that your dog can ingest that can cause acute renal failure include:

• Poisonous plants
• Antifreeze (Ethylene glycol)
• Aminoglycoside antibiotics
• Grapes or raisins
• NSAIDs

A build-up of calcium or other substances in your dog’s body can occur due to disease elsewhere in your dog, leading to acute renal failure. When kidneys don’t receive enough oxygen (like in the case of a blood clot blocking blood flow to the kidneys) kidney function can be impacted; this is called ischemia. Possible reasons for renal ischemia include:

• Dehydration
• Trauma
• Anesthesia
• Sepsis
• Shock
• Hypothermia
• Burns
• Surgery

Infections such as leptospirosis and borreliosis can also lead to acute renal failure.

Diagnosing acute renal failure will require that the veterinarian conduct a physical exam and obtain your dog’s history, including what your dog has recently eaten, medications he has taken and how he has been acting over the last few weeks and months. He will likely request blood work, urine testing, and an abdominal ultrasound.

Your veterinarian will seek to determine if your dog has acute renal failure or a chronic renal condition (or a combination of both). In cases of acute renal failure or acute kidney injury, your dog will typically show the following:

• Symptoms come on suddenly
• No history of major weight loss (exception would be if there is an underlying condition in your dog)
• Pain in the area of the kidneys when examined.
• Blood work will show blood urea nitrogen (BUN) and creatinine values to be elevated; rapid increases of BUN, creatinine and phosphorus may be noted when your dog is experiencing acute renal failure.

Should acute renal failure be diagnosed or seem likely, further testing may be requested by your veterinarian. This could include blood pressure measurement as well as testing for inflammatory and infectious diseases. Your veterinarian may choose to conduct a renal biopsy to determine the severity and extent of the disease as well as the potential for reversing it. Your veterinarian will want to determine if the acute renal failure is due to an underlying disease or poison in order to come up with the best course of treatment.

The veterinarian will try to understand what caused the kidney injury in order to provide appropriate treatment.  For example:

• For ethylene glycol toxicity: 4-methylpyrazole or ethanol
• If your veterinarian suspects leptospirosis, antibiotics should be started even before the infection is confirmed; recommendations include doxycycline or for those dogs who cannot tolerate doxycycline, penicillin

If your dog is dehydrated or not eating, your veterinarian may order intravenous fluids or a feeding tube. Should your dog not be urinating enough (or at all) treatment may include intravenous fluids, a catheter in your dog’s bladder and in some cases, medication. It is important that your veterinarian monitor the hydration of your dog to avoid over hydration. Your veterinarian will consider daily fluid administration based on the needs of your dog until his renal function and condition show improvement. Should the creatinine level of your dog be greater than 10mg/dL once he is rehydrated, a feeding tube will likely be recommended.

Should these treatments not work, and your dog is not producing urine, your veterinarian will consider kidney dialysis or a kidney transplant.  It is important to remember that the maintenance phase of renal failure can last for weeks in some dogs; it is only after this phase that the kidney can begin to repair itself and begin to function.

Your dog’s recovery will depend on the cause of his renal failure. Once the cause of the renal failure has been identified, your veterinarian will explain the treatment regimen for the underlying issue and will let you know what follow-up is necessary. If the cause is identified and treated early, and renal damage is not too extensive, it is possible for the kidney failure to be reversed, as kidneys have a significant potential to regenerate.