Original article: How to Diagnose and Treat Feline Infectious Peritonitis (FIP)
8/5/2019, Translation 1/25/2021
Feline peritonitis (FIP) is a relatively rare disease that usually occurs in cats less than two years of age or if they have lived or are living in a group with multiple cats. FIP is caused by an inadequate immune response to a common virus called feline coronavirus. Most cats that get the virus can eliminate it without any lasting consequences, but some cats have a virus mutation that leads to the development of this devastating disease. There are two forms, wet and dry. If a cat develops FIP, it is almost always fatal. Learn to recognize the symptoms of FIP, take your cat to a veterinarian and have it tested. If the diagnosis is confirmed, there is no official treatment, but you can provide supportive care to the cat.
This procedure was written before the GS441524 FIP treatment boom. So one last point could be added here - the real cure and the mention that FIP may not always end in death.
Recognition of FIP symptoms

1. Notice the change in appetite. Cats can stop eating or reduce the amount of food they consume each day. Because of this, the cat may begin to lose weight. In kittens, this may slow their growth. These symptoms are characteristic of wet FIP.
- Despite poor food intake and weight loss, the abdomen may swell and the cat may look like a balloon.
- A cat can also have diarrhea.

2. Monitor for breathing problems. Infectious feline peritonitis can affect the cat's respiratory system. The cat may have difficulty breathing and wheezing. He can also sneeze and have a cold. These symptoms are also characteristic of wet FIP.
- These respiratory symptoms may be associated with the formation of fluids in the chest cavity.

3. Pay attention to the health of the cat. The second type of FIP is the dry (non-effluent) non-effluent form. If the cat has this form, it will be in poor health. Kittens may have slow growth and do not develop as they should. Cats may also show symptoms of jaundice (yellow inner eyelids) and anemia. Matte coat is also common.
- A cat may have a fever.
- Cats with FIP may show symptoms of depression or lethargy.

4. Watch for eye problems. The dry version of FIP can affect the eyes. The eye may be inflamed and swollen. You may notice redness in the whites and in some cases the eyes may even bleed. Cats' eyes can change color, usually to a brown hue.
- The cat can go blind.
- Eye problems may be the only manifestation of this disease.

5. Watch for neurological symptoms. FIP can affect the nervous system. The cat may have coordination problems, so it may fluctuate, have balance or gait problems. He may also have tremors or seizures.
FIP diagnosis

1. Find out if your cat has been at risk of infection. The disease usually affects cats under 2 years of age. It occurs more often in larger feline communities. The most common mode of infection is contact with infected feces. People can transmit the virus on their clothes. If an infected cat comes in contact with an object, the virus can be transmitted to the object.
- The virus is often excreted in the faeces. The virus will live up to 36 hours, although in colder climates it may last longer.
- In most cats, the virus causes diarrhea and then the body gets rid of it itself.
- Feline coronavirus is not transmissible to humans and dogs.

2. Take the cat to the vet. FIP is difficult to diagnose, so see a veterinarian as soon as you suspect a problem, which can help with diagnosis. Make sure you tell your veterinarian about all the symptoms to help him get all the facts.
Sometimes FIP can only be diagnosed by excluding other diseases.

3. Have blood tested. The first thing a veterinarian is likely to do is a blood test. Anti-coronavirus antibodies are detected. However, these antibodies only mean that the cat has been exposed to the virus, not that it has FIP. The veterinarian can make a diagnosis based on the blood test and the symptoms that the cat has.
- There may be certain abnormalities in the blood test that may indicate FIP. The veterinarian may also perform a titration test on the FIP.
- The blood veterinarian will also assess the function of the liver and kidneys.

4. Have the thoracic and abdominal cavities examined. The veterinarian may perform an X-ray to determine if there is fluid in the abdomen or chest. If the X-ray shows fluid, the veterinarian may take a sample for further testing.
- This is often enough for a diagnosis, but in some cases it is not yet possible to make a definitive diagnosis.

5. Have a biopsy done. Diagnosing the dry form of FIP is difficult because it is not present in the fluid in the organs. If the differential diagnosis does not lead to a diagnosis, the veterinarian may biopsy the affected organs.
FIP Treatment

1. When the FIP is dry, provide support for the cat. There is no cure for both types of FIP. However, dry cats can live for several months if they are still eating, have not developed neurological symptoms and do not have anemia. Providing quality nutritious food to a cat can help survive for several months.
- If a cat develops anemia, she may need a blood transfusion.

2. When the FIP is wet, you can aspirate some of the liquid. Wet form cats generally do not live as long as dry form ones. To prolong the life of the cat at least a little, you can suck some of the fluid out of your chest and abdomen.
- Fluid aspiration can cause significant protein loss, which can make the condition worse.

3. Give the cat medication. The veterinarian may give the cat antibiotics if it develops an infection. Immunosuppressants are sometimes given to reduce antibodies. If cats have eye problems, they may be prescribed corticosteroids.

4. Decide when it is time for euthanasia. Almost every case of FIP is fatal and the virus is incurable. Most treatments are only supportive to improve a cat's quality of life for weeks or months. Many veterinarians suggest that cats diagnosed with FIP be killed.
- If your cat is diagnosed, you and your family must decide on the most humane and appropriate treatment.