Acute renal failure—better known as acute kidney injury—is a condition that has a sudden onset and can make your dog feel extremely ill. Symptoms of acute kidney injury include lethargy, not eating, vomiting, and abdominal pain. Most dogs will experience a sudden increase in thirst and urination. This may progress into drinking little to no water and hardly urinating.
There are several other diseases that share symptoms with acute kidney injury. Your dog should be evaluated by your veterinarian immediately if he is showing the symptoms mentioned above. If your veterinarian is unable to see your dog immediately, take him to the closest emergency veterinary hospital for evaluation.
Causes of Acute Kidney Injury in Dogs
There are many causes of acute kidney injury. These can include infections, toxins, certain medications, obstruction of the urinary system, and diseases that cause severe inflammation of the body.
Infectious causes include pyelonephritis and leptospirosis. Pyelonephritis is also known as a kidney infection. Pyelonephritis typically starts as a bladder infection. Bacteria in the bladder can ascend to the kidneys via the ureters (the tubes that connect the kidneys to the bladder) and cause a kidney infection.
Leptospirosis is a bacterial infection caused by the bacteria Leptospira. Leptospirosis can infect many organs in a dog’s body, including the kidneys, liver, heart, and lungs. See the article “Leptospirosis in Dogs” for more information about leptospirosis.
Toxins that can cause acute kidney injury in dogs include tartaric acid and ethylene glycol. Ethylene glycol is found in automotive antifreeze. Tartaric acid is found in grapes, raisins, Zante currants, and tamarind. Zante currants are also known as Corinthian raisins. Currants in the Ribes genus—such as blackcurrant, redcurrant, white currants, and European gooseberries—do not contain tartaric acid and are not considered toxic to dogs.
Ingesting an overdose of cholecalciferol (also known as vitamin D3) can cause acute kidney injury in dogs. Dogs can overdose on cholecalciferol by ingesting vitamin D3 supplements, their owner’s medicated skin creams that contain vitamin D3, or rodenticide (mouse poison) that contains cholecalciferol.
Certain medications have been associated with an increased risk of developing acute kidney injury in dogs. These medications include antibiotics in the aminoglycoside drug class, such as gentamicin and amikacin. The antifungal drug amphotericin B is also known to cause acute kidney injury in dogs.
Other drugs that can cause acute kidney injury are the chemotherapy drug cisplatin and radiographic contrast agents used for imaging with CT and MRI. An overdose of a prescribed non-steroidal anti-inflammatory drug (NSAID)—such as carprofen or deracoxib—or ingestion of an NSAID made for humans—such as ibuprofen or acetaminophen—can cause acute kidney injury in dogs.
Acute kidney injury can also be caused by an obstruction of the urinary system. A urinary obstruction is one that either blocks a dog’s ability to urinate (urethral obstruction) or a kidney’s ability to empty urine into the bladder (ureteral obstruction). A urethral obstruction can be caused by one or more bladder stones, a tumor of the bladder or urethra, or an enlarged prostate. A ureteral obstruction can be caused by a kidney stone or a tumor of the ureter.
Dogs experiencing an illness that causes a severe inflammatory reaction in the body may develop acute kidney injury. Conditions such as sepsis, pancreatitis, and acute shock release inflammatory mediators that can damage the kidneys.
Diagnosis of Acute Kidney Injury in Dogs
If your dog was observed ingesting a known renal toxin, your veterinarian may request that you contact an animal poison control helpline (such as ASPCA Poison Control or Pet Poison Helpline) to determine if the amount of toxin ingested puts him at risk for acute kidney injury. Your veterinarian and the toxicology consultant with poison control will recommend diagnostics and treatments based on the type of toxin and how much of it your dog ingested.
For other potential causes of acute kidney injury, your veterinarian will want to complete blood work (including a complete blood count and chemistry panel) and a urinalysis. A urine culture and sensitivity will be recommended if your veterinarian suspects your dog may have pyelonephritis. Testing for leptospirosis may also be recommended.
Abdominal radiographs (x-rays) may be recommended to look for stones in your dog’s urinary system. An abdominal ultrasound may be recommended to examine the architecture of your dog’s kidneys to help determine the cause of acute kidney injury.
Treatment for Dogs Suffering from Acute Kidney Injury
Dogs with acute kidney injury should ideally be hospitalized. Treatment includes administration of intravenous fluids and medications to address nausea, vomiting, and pain. Antibiotics may be administered if an infectious cause of acute kidney injury is suspected.
Your dog’s urine output will be closely monitored and compared to the amount of fluids being administered intravenously. This helps determine how well the kidneys are responding to treatment.
Dogs that are in the advanced stage of acute kidney injury may benefit from renal hemodialysis. Hemodialysis removes waste products from the blood that are normally removed by healthy kidneys. Multiple sessions of hemodialysis will be required until the kidneys have recovered and can begin filtering out waste products on their own.
Acute kidney injury that has been caused by an NSAID overdose may respond to two different treatments, either used singly or in combination. The first treatment is called therapeutic plasma exchange (TPE). NSAIDs bind to proteins found in plasma (the liquid portion of blood). TPE involves separating plasma from the red blood cells and replacing it with plasma from a canine donor along with intravenous fluids.
The second treatment that can help eliminate a toxic dose of an NSAID from the body is intralipid emulsion (ILE) therapy. ILE involves the intravenous administration of a fat emulsion solution. The NSAID molecules are drawn to the emulsion and bind to it, facilitating its removal from the body.
Hemodialysis and TPE are only available at certain specialty and veterinary teaching hospitals. ILE therapy is more widely available at many specialty and emergency hospitals.
Prognosis for Dogs Diagnosed with Acute Kidney Injury
The prognosis for a dog experiencing acute kidney injury depends on the cause and the severity of laboratory abnormalities. Dogs with acute kidney injury caused by leptospirosis typically have a good prognosis with treatment. Acute kidney injury caused by ethylene glycol carries a poor prognosis.
Dogs that have severe elevation of their kidney values, severely low calcium, and high phosphorus, anemia, and decreased urine production have a guarded prognosis for recovery. Dogs that do not improve or worsen with hospitalization and intravenous fluid therapy have a poor prognosis.
Dogs that respond to therapy may make a full recovery and not suffer any long-term effects of their illness. Some dogs may experience short-term damage to their kidneys that takes several weeks to months to resolve. Other dogs may have some level of chronic kidney disease for the remainder of their lives following recovery from acute kidney injury.
