Kidney Toxicity in Cats

Kidney toxicity is so serious because it causes dehydration, electrolyte disturbance, pH imbalance, and a buildup of metabolic waste in the blood. If you suspect your cat has ingested a toxic substance, it is important to seek help from a veterinarian immediately to reverse the damage.

The kidneys are your cat's blood filtration system. They maintain fluid balance and the appropriate balances of nutrients in the blood. When your cat ingests nephrotoxins (substances that are toxic to the kidneys of cats), the toxins can cause acute renal failure, a very serious situation that can be fatal without early veterinary intervention.

Symptoms of acute renal failure caused by kidney toxicity are common to many forms of kidney disease. Symptoms may onset suddenly and progress quickly. Contact a veterinarian immediately if your cat is exhibiting one or more of the following symptoms of acute renal failure:

• Loss of appetite
• Listlessness
• Vomiting
• Blood in vomit
• Fruity breath odor
• Less frequent or more frequent urination
• Increased or decreased urine volume
• Seizures

If you see your cat ingest a toxic substance, do not wait until she begins to manifest the symptoms of acute renal failure. The condition progresses rapidly and early intervention is the key to an improved prognosis.

The cause of acute renal failure in cats is the ingestion of a substance that is toxic to the kidneys. The most common substances that lead to kidney toxicity in cats include

• Acetaminophen-containing medications such as Tylenol, Dayquil, Excedrin, Robitussin Cold, Cough and Flu, Sudafed PE, Theraflu Sore Throat
• Ethylene glycol, such as that found in antifreeze or de-icing agents for windows
• Plants, especially lilies
• Permethrin, a substance used for flea and tick control
• Amphetamines
• NSAIDs, such as ibuprofen and naproxen
• Insecticides, herbicides, rat poison
• Poisonous mushrooms
• Citrus oils, such as those found in household cleaning products

There are also certain foods with toxic effects on cats that may manifest as acute renal failure, including: 

• Alcohol
• Grapes or raisins
• Caffeine-containing beverages
• Xylitol-containing substances, such as candy, gum or certain medication tablets

In order to confirm a diagnosis of acute renal failure due to kidney toxicity, your veterinarian will begin with a thorough physical exam and collect a comprehensive history of your cat's diet, medication management and whereabouts. Your veterinarian will palpate your cat's abdomen and limbs for edema, or fluid accumulation. He may also search your cat's mouth for ulceration and pinch skin for signs of dehydration. Obviously, history of ingestion of a toxic substance should be reported to your veterinarian along with any changes in urine output, eating habits, disposition, or other pertinent medical history regarding the heart and vascular system, liver and kidneys. 

Following the physical exam, your veterinarian will likely collect blood and urine samples to culture. Urinalysis of a cat with acute renal failure may show sloughed kidney cells, glucose molecules, kidney enzymes, myoglobin, hemoglobin or an excess of certain electrolytes. Blood samples of cats with kidney toxicity are characterized b y increased blood urea nitrogen, creatinine, phosphorus and pH imbalance.

After a diagnosis of kidney injury or failure, your veterinarian will focus on determining whether the kidney failure is the result of kidney toxicity or chronic renal failure, as those conditions require different treatment and management. Your veterinarian can perform certain tests or investigate values in the blood and urine cultures that differentiate one condition from the other.

If the toxin responsible for kidney toxicity is known, your veterinarian can administer antitoxins to target that agent. Otherwise, your veterinarian will likely prescribe supportive therapies, such as rehabilitative fluids and electrolytes or intravenous fluids such as saline or lactated Ringer's solution. 

Your veterinarian may also recommend therapy to increase urine output, and thereby the release of toxic substances and metabolic waste. Diuretics, administered judiciously, are ideal for this purpose, though they are contraindicated for some cats.

Other common treatments for cats with acute renal failure due to kidney toxicity include vasodilators to treat renal hypertension and dialysis to rapidly remove toxic substances and waste products from the blood.

The survival rate for chronic renal failure is roughly fifty percent. The survival rate is much higher for cats who receive early, aggressive intervention.

Your cat will require a follow-up appointment within a week or two of returning home. Electrolyte panels will be performed to ensure complete recovery. Blood and urine cultures may also be performed. 

Cats who have suffered acute renal failure from the ingestion of nephrotoxins are at increased risk for chronic kidney disease down the road. This means they require regular follow-up visits to track changes in urine output, lab values and overall health. 

It is also important to ensure your cat is hydrated and maintaining appropriate urine output. Changes in thirst and urination are often the first signs of another episode of renal toxicity.