Introduction

Feline infections peritonitis (FIP) can be difficult and frustrating to diagnose, because there are no specific, reliable tests for this disease. Frequently, the attending veterinarian will make the diagnosis based upon the cat’s observable symptoms, together with the results of blood tests, radiographs (X-rays) and possibly tissue biopsies.

How FIP is Diagnosed

Feline infectious peritonitis is often suspected based upon a cat’s presenting clinical signs, which typically include fever, ocular (eye) and nasal discharge, weakness, lethargy, loss of appetite, weight loss and depression. Labored breathing, dehydration, vomiting, diarrhea and neurological abnormalities are also commonly present. Routine blood work, including a complete blood count and a serum biochemistry profile, can reveal the elevated liver enzymes and abnormal blood protein levels that typically are present in cats with FIP. Thoracic (chest) and abdominal radiographs may disclose an abnormal accumulation of fluid in those body cavities. This is called “effusion,” or “ascites.” Fluid aspirated from the chest or abdomen of cats with the wet form of this disease can be analyzed by a number of different laboratory tests. Blood samples from cats with extremely elevated blood protein (globulin) levels can be submitted for serum protein electrophoresis. Cerebrospinal fluid samples also can be analyzed for protein content, which typically is elevated in affected cats. However, the only definitive way to diagnose FIP is to take a surgical biopsy of an affected organ – often the intestine – and to analyze it microscopically by a process called histopathology. Other organs commonly affected by FIP are the liver, eyes, brain, kidney and pancreas. Most cats with the dry form of this illness eventually develop eye or brain symptoms, or both.

Special Notes

Unfortunately, both the wet and dry forms of feline infectious peritonitis are inevitably fatal. Cats with the wet form of FIP usually die within a matter of months after the onset of observable symptoms. Cats with the dry form of this disease usually have a longer, more chronic illness, but it also invariably ends in death. There is no effective treatment for FIP at this time, although this disease is the subject of a great deal of focused research. Euthanasia is usually recommended to relieve the suffering of affected animals.