Acute Kidney Injury in Cats
Acute kidney injury is a sudden attack on the kidneys in a cat that was previously well. Within hours to days, the kidneys stop filtering blood correctly: waste products and certain minerals build up in the body and poison it. This is not a...
What is it?
Acute kidney injury is a sudden attack on the kidneys in a cat that was previously well. Within hours to days, the kidneys stop filtering blood correctly: waste products and certain minerals build up in the body and poison it.
This is not a disease with a single cause but rather a clinical pattern: a poison, loss of blood flow, an infection, or a blockage of the urinary tract can be behind it.
This is an emergency. Unlike chronic kidney disease, which develops over months and does not resolve, an acute injury may be partially or fully reversible if treated very early.
Key point
Life-threatening emergency. A cat that has stopped urinating almost completely, or that may have contacted lilies, antifreeze, or human medication, must be seen immediately, even if the cat still appears well.
Commonly observed signs
These signs are neither exhaustive nor specific. Only a veterinarian can establish a diagnosis.
Related signs — each one links to its page:
The cat suddenly stops eating, becomes withdrawn and hides.
Vomiting, sometimes diarrhea.
Dehydration: dry gums, skin that returns slowly when gently pinched, sunken eyes.
Small sores or ulcers in the mouth and ammonia-smelling breath, related to the buildup of waste in the blood.
Urine production drops sharply or stops: far fewer wet clumps in the litter box, without seeing the cat strain.
Conversely, in some cats urine output becomes very heavy.
In severe cases: extreme weakness, cold body, abnormal breathing, tremors or seizures.
When to consult without delay
This list does not replace veterinary advice. It gathers situations that justify a prompt consultation.
Causes and risk factors
Toxic causes—absolutely essential to know:
– lilies and daylilies: all parts of the plant, pollen and even vase water are highly toxic to the cat's kidneys;
– antifreeze from cars (ethylene glycol), which tastes sweet: even a small amount licked from the floor can cause serious injury;
– over-the-counter anti-inflammatory medications meant for humans, and certain other drugs, given by mistake or swallowed accidentally;
– paracetamol, highly dangerous to cats, which damages mainly the blood and liver (see dedicated sheet).
Loss of blood flow to the kidneys: severe dehydration, shock, bleeding, anesthesia, heart disease.
Kidney infection (pyelonephritis).
Prolonged blockage of the urinary tract: urine cannot drain and the kidneys eventually suffer.
Lilies or daylilies in the home, in bouquets or pots.
Access to a garage, parking area or yard where antifreeze may have spilled.
Human medications left within reach, or given to the cat without veterinary advice.
Older cat or one already living with kidney disease, more vulnerable to dehydration or medication effects.
Male cat prone to urinary blockage.
Diagnosis and care
Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.
The veterinarian first checks that the bladder is not blocked: in a cat that urinates little, it is important to tell whether the kidneys have stopped producing urine or the bladder is full and cannot empty. The vet will ask whether your cat may have touched lilies, antifreeze, or medication—bring the packaging or plant name if you can. A blood test measures the waste products the kidneys should remove and the minerals that can dangerously build up in the heart. A urinalysis, ultrasound of the kidneys, and blood pressure check complete the assessment. The veterinarian will also distinguish acute kidney injury from chronic kidney disease, which requires different treatment.
Treatment
The cat is hospitalized. Intravenous fluid therapy is the cornerstone of treatment: it corrects dehydration, supports kidney function, and helps eliminate waste products. The amount of urine produced is closely monitored, sometimes with a urinary catheter, to adjust care. The underlying cause is treated as soon as it is identified: decontamination after lily exposure, relief of urinary blockage, treatment of infection. For antifreeze, an antidote exists but is effective only if given very early after ingestion, before signs appear. Medications for vomiting, nausea, and stomach acid are given alongside appropriate nutrition, sometimes through a feeding tube. In the most severe cases, blood filtration (dialysis) may be offered at specialized centers. Never induce vomiting in your cat and do not give any human medication without veterinary advice.
Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.
Prevention
Do not keep lilies or daylilies in your home where a cat lives, not even in a bouquet. Store antifreeze out of reach, clean up any spills, and watch for leaks from vehicles. Never give your cat medication intended for humans, and keep all medications in a locked cabinet. Make sure your cat drinks enough water, especially during hot weather and if your cat is elderly. For an elderly cat, a blood test before anesthesia or starting new medication helps identify potential kidney risks.
Possible complications
Potassium buildup in the blood, which can severely disrupt heart rhythm. Complete loss of urine production, a very serious situation. Fluid overload if the cat stops urinating while receiving intravenous therapy, requiring close monitoring. Progression to chronic kidney disease if the kidneys only partially recover. Death in severe cases or when treatment is delayed.
When to see a veterinarian
Your cat may have contacted lilies, licked antifreeze, or swallowed human medication, even if the cat seems fine: immediate emergency. The cat has almost stopped urinating and is not eating: immediate emergency. The cat strains in the litter box without producing urine, especially if male: immediate emergency—this is likely a urinary blockage. The cat vomits repeatedly and becomes lethargic. The cat has sores in the mouth or ammonia-scented breath and refuses to eat. Your cat, already being treated for kidney disease, suddenly deteriorates.
Prognosis
The outlook depends on the cause, how quickly treatment is started, and how much urine the cat is still producing.
Some cats recover completely; others are left with weakened kidneys and require ongoing monitoring similar to that for chronic kidney disease.
After exposure to lilies or antifreeze, the chances are much better when treatment begins before signs appear: every hour matters.
Frequently asked questions
What is the difference with chronic kidney disease?
Acute kidney failure occurs suddenly in a cat that was fine just days earlier, and it can sometimes be cured if treated quickly. Chronic kidney failure develops slowly over months: the cat has been drinking and urinating a lot for a long time and gradually loses weight. A chronic condition can also suddenly worsen: only a veterinarian can tell the difference.
My cat is barely urinating: is it kidney disease or a blockage?
Watch him at the litter box. If he strains for a long time, keeps returning and nothing comes out, it's likely a urinary blockage, especially in males. If instead he barely goes to the litter box at all and doesn't strain, it's more likely his kidneys that are no longer producing urine. In both cases, it's an immediate emergency.
Are lilies really that dangerous?
Yes. In cats, all parts of the lily and daylily are toxic to the kidneys: leaves, flowers, pollen, and even the vase water. Even a small amount of pollen licked from the coat can be enough. At the slightest doubt, consult a veterinarian immediately without waiting for the first signs to appear.
Can the kidneys heal?
Sometimes, yes. Unlike the chronic form, acute kidney disease can improve partially or completely if the cause is treated quickly and the cat is supported during recovery. However, some cats are left with more fragile kidneys and subsequently require regular monitoring.
References
Content reviewed by the TunisieVet editorial team · Updated 11 October 2026
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