What is FIP?
FIP stands for Feline Infectious Peritonitis, and it is a leading infectious cause of death in cats. FIP occurs when a cat’s immune system reacts inappropriately to feline coronavirus, a common enteric virus (attacks the gastrointestinal cells) that usually causes either mild or no clinical signs.
FIP causes a vasculitis (inflammation of blood vessels) and the clinical signs that a cat develops depends on which blood vessels are damaged, and which organ or organs the damaged blood vessels supplied.
In acute disease, when there are many blood vessels affected the effusive (fluid accumulating or ‘wet FIP’) form of the disease is often seen – with clinical signs like abdominal effusion (ascites, or ‘pot belly’), thoracic effusion (fluid accumulating around the lungs) and pericardial effusion (fluid accumulation in the sac around the heart).
In the more chronic or non-effusive form (‘dry FIP’), the immune system attempts to contain infection, creating growths consisting of immune cells (particularly macrophages) called ‘granulomas’. You may notice a yellowish tinge to the skin (jaundice) or abnormalities inside the eye (such as bleeding).
How is FIP diagnosed?
FIP is a notoriously difficult condition to diagnose. There is not one single test that can definitively give an answer – apart from a post-mortem. Vets have to piece together clues from the history as well as a thorough physical examination, blood tests and evaluations of any fluid or masses present.
What symptoms does a cat with FIP show?
Clinical signs to look out for include poor appetite, weight loss, recurring fevers, lethargy, pot-belly appearance, difficulty breathing, abnormalities in the eyes, loss of balance, change in personality.
All of these clinical signs can also be attributed to other curable diseases, so a vet evaluation is essential if your cat shows any of these signs.
How is FIP treated?
Unfortunately, FIP is generally a fatal condition. In many cases if the cat has a good quality of life, immunosuppressants and antibiotics may be prescribed to help keep the cat comfortable for longer. An experimental treatment with interferon omega (an anti-viral drug) is also available and may in rare cases effect remission or cure.
Author Lucie Allcutt MRCVS