Acute kidney failure – more commonly 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 can progress to drinking little or no water and barely urinating.
There are several other diseases that share symptoms with acute kidney injury. Your dog should be evaluated by your veterinarian immediately if it exhibits the above symptoms. If your vet can’t see your dog right away, take him to the nearest 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 usually starts as a bladder infection. Bacteria in the bladder can travel up to the kidneys through the ureters (the tubes that connect the kidneys to the bladder) and cause a kidney infection.
Leptospirosis is a bacterial infection caused by 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 genus Ribes – such as black currants, red currants, 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 containing vitamin D3, or rodenticide (mouse poison) containing cholecalciferol.
Certain medications are associated with an increased risk of developing acute kidney injury in dogs. These drugs include antibiotics from the aminoglycoside 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 CT and MRI imaging. Overdosing on a prescription nonsteroidal anti-inflammatory drug (NSAID)—such as carprofen or deracoxib—or ingesting 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 obstruction of the urinary system. A urinary obstruction is one that either blocks the dog’s ability to urinate (urethral obstruction) or the kidney’s ability to empty urine into the bladder (ureteral obstruction). An obstruction of the urethra can be caused by one or more stones in the bladder, a tumor of the bladder or urethra, or an enlarged prostate. Ureteral obstruction can be caused by a kidney stone or a ureteral tumor.
Dogs that have a disease that causes a severe inflammatory reaction in the body can 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 is observed ingesting a known kidney toxin, your veterinarian may request that you contact an animal poison control hotline (eg. ASPCA Poison Control or Pet Helpline) to determine whether the amount of toxin ingested puts him at risk of acute kidney injury. Your veterinarian and poison control toxicology consultant will recommend diagnosis and treatments based on the type of toxin and how much your dog ingested.
For other potential causes of acute kidney injury, your vet will want to complete blood work (including a complete blood count and chemistry) and urinalysis. A urine culture and sensitivity will be recommended if your vet suspects that your dog has pyelonephritis. Testing for leptospirosis may also be recommended.
Abdominal X-rays (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 determine the cause of the acute kidney injury.
Treatment of dogs suffering from acute kidney injury
Dogs with acute kidney injury should ideally be hospitalized. Treatment includes intravenous fluids and medications to manage 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 carefully monitored and compared to the amount of fluids given intravenously. This helps determine how well the kidneys are responding to treatment.
Dogs in advanced stages of acute kidney injury may benefit from renal hemodialysis. Hemodialysis removes waste products from the blood that are normally removed by healthy kidneys. More hemodialysis sessions will be needed until the kidneys recover and start filtering waste products on their own.
Acute kidney injury caused by NSAID overdose may respond to two different treatments, used individually or in combination. The first treatment is called therapeutic plasma exchange (TPE). NSAIDs bind to proteins found in plasma (the liquid part of the blood). TPE involves separating plasma from red blood cells and replacing it with canine donor plasma along with intravenous fluids.
Another treatment that can help eliminate a toxic dose of NSAIDs from the body is intralipid emulsion (ILE) therapy. ILE involves the intravenous administration of a fat emulsion solution. NSAID molecules are attracted to the emulsion and bind to it, facilitating its removal from the body.
Hemodialysis and TPE are only available in certain specialized and veterinary hospitals. ILE therapy is more widely available in many specialty and emergency hospitals.
Prognosis for dogs diagnosed with acute kidney injury
The prognosis for a dog that experiences acute kidney injury depends on the cause and severity of the laboratory abnormalities. Dogs with acute kidney injury caused by leptospirosis usually have a good prognosis with treatment. Acute kidney injury caused by ethylene glycol has a poor prognosis.
Dogs with severely elevated kidney values, very low calcium and high phosphorus, anemia, and decreased urine production have a cautious prognosis for recovery. Dogs that do not improve or worsen after hospitalization and intravenous fluid therapy have a poor prognosis.
Dogs that respond to therapy can make a full recovery and have no long-term effects from their disease. Some dogs may experience short-term kidney damage that takes several weeks to months to resolve. Other dogs may have some level of chronic kidney disease for the rest of their lives after recovering from an acute kidney injury.
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