Ascites is the medical term for build-up of fluid in the belly. If severe, it can interfere with breathing and become life-threatening. It can have many causes and affect cats of all breeds and ages.

Some diseases will cause water to leak from the blood vessels in the abdomen, and this water will build up in the spaces between the organs. Other diseases cause the body to excrete fluid into this space, usually to combat an infection. Blood, bile or urine can also build up inside the tummy after an injury or internal damage. Always speak to a vet if you notice swelling of the belly, this is even more urgent if the breathing has changed or your cat is listless or weak.

What to do if you suspect your cat has ascites

Always speak to a vet if your cat’s tummy seems swollen or has an abnormal shape.

Most of the time, there’s a serious condition behind this change.

Call us in the Joii app if you’re unsure.

Common causes of ascites in cats

• Heart failure

• Liver failure

• Kidney failure

• Feline Infectious Peritonitis (FIP) infection

• Lymphoma

• Tumour interfering with blood flow back to the heart

• Internal bleeding from an injury or a tumour

• Infection from a penetrating injury or leakage from the gut

• Urinary bladder or gallbladder leaking after an injury

When to worry about ascites in cats

Speak to a vet urgently if:

• Breathing is fast or laboured

• Swelling is rapidly worsening

• They are lethargic or struggling to stand up

Advice is available 24/7 in the Joii app if you are unsure or would like to discuss this problem further.

How to prevent ascites in cats

Regular health checks will increase the likelihood of detecting many of the causes of ascites early.

In most cases, this improves the chances that treatment will be effective.

How to know if your cat has ascites

• Belly fluid may accumulate very quickly or build up slowly over time.

• The tummy will have a round, pendulous shape, especially when the cat is standing up.

• If they aren’t too painful or stressed, you may be able to feel a wavy/sloshing movement if you press gently on the tummy with them laying on their side.

• Large amounts of fluid can start compressing the diaphragm and chest, which can cause severe breathing problems.

Home remedies for ascites in cats

Weight gain and other diseases may sometimes be confused with ascites.

If belly fluid is truly present, it’s always caused by a serious, often life-threatening disease. An accurate diagnosis and veterinary treatment are essential.

Veterinary treatment of ascites in cats

• If the swelling is interfering with breathing, your vet will drain some of the fluid. This must be done carefully to avoid:

  • Introducing infection into the belly

  • Damaging internal organs

  • Dehydration

  • A drop in blood protein levels

• Further treatment will depend on the cause of fluid build-up. Determining this may require:

  • Taking a sample of the fluid in the abdomen and analysing it

  • Blood tests to check organ function (especially kidneys and liver) and blood protein level

  • Testing for specific infections, like FIP

  • Urine tests to check kidney function and protein losses in urine

  • X-rays and ultrasound scans of the chest and abdomen

• Once a diagnosis is known or suspected, treatment may involve:

  • Surgery, if damage to an internal organ or a tumour is suspected

  • Medication for heart, kidney or liver disease

  • Diet changes and supportive care

  • Antiviral treatment for FIP

  • Antibiotics if an infection is present. Many types of infection will also require the abdomen to be flushed and cleaned surgically

Is my cat at higher risk of developing ascites?

Because there are many possible causes of ascites, this can sadly happen to any cat. The risk of specific causes of ascites, however, may be higher in some cats:

• Some breeds (Maine Coon, Ragdoll, British Shorthair, Persian, Siamese, Burmese, Sphinx, Devon rex) are at higher risk for heart disease

• Kittens may be at higher risk for severe forms of FIP

• Older cats are at higher risk for some types of tumours

Other causes of ascites in cats

There are other causes of ascites that are less common, such as:

• Rat poison or anticoagulant intoxication - in rare cases this can cause bleeding into the abdomen

• Tumours and cancer can sometimes cause belly fluid by causing inflammation