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19 – THE PYREXIC CAT 373

Diagnosis from an effusion is used for analysis. Note that when
whole blood is used for analysis, positive results do not
Histopathology of affected tissues provides the only
correlate to FIP.
definitive antemortem diagnosis. The classic FIP lesion
● To date, no nucleoprotein sequences specific for
is pyogranulomatous infiltration around venules.
FIP-coronavirus have been identified. Some non-
The following are typical abnormalities associated pathogenic coronaviruses have systemic spread,
with FIP. All asterisked items must be present for a therefore finding coronavirus nucleoprotein by
high likelihood of FIP; if any one parameter is not PCR in the systemic circulation or tissue is not
present, FIP is unlikely. A negative coronavirus (“FIP”) indicative of FIP-coronavirus infection.
titer suggests FIP is not the cause of the fever,
Except where the classical effusive fluid is present,
although a few cats with the effusive form of the dis-
definitive diagnosis of FIP requires organ biopsy and
ease are titer negative.
demonstration of classical histopathological lesions.
3
Lymphopenia (< 1.5 × 10 cells/μl).* Occurs in many
Various non-specific abnormalities may be evident on
cats with FIP, and many cats without FIP.
laboratory tests, including increased total white cell
Hyperglobulinemia > 51 g/L [> 5.1 g/dl].* Present in 50% count, mild to moderate anemia, and increased concen-
of cats with effusive FIP and 70% with non-effusive FIP. trations of bilirubin, liver enzymes, BUN, creatinine,
fibrinogen, globulin and mild proteinuria.
High coronavirus/FIP titers (>= 1:160).* Present in
most cats with FIP and many healthy cats without FIP. Disseminated intravascular coagulopathy (DIC) is
evident in some cats.
The effusive or wet form of FIP has pleural and/or
abdominal effusion with: CSF typically has increased protein (> 2 g/L) and cell
● Protein 35 g/L [> 3.5 g/dl]. counts (>100 cells/ml) which are predominantly non-
● Albumin:globulin ratio < 0.8. lytic neutrophils.
● Protein electrophoresis should demonstrate a poly-
clonal gammopathy with gamma globulins repre- Differential diagnosis
senting > 32%.
● Cell count varies from low to moderate (1500 to Ocular signs: toxoplasmosis, fungal agents.
more than 25 000 cells/μl) and mainly non-lytic
Neurologic signs: toxoplasmosis, neoplasia (e.g., lym-
neutrophils, lymphocytes and macrophages.
phoma), trauma, congenital abnormalities in young cats.
“FIP titers” reported by laboratories are either corona-
Other clinical signs: rule out other diseases associated
virus titers or titers to the 7B protein in coronavirus.
with the apparent organ dysfunction.
Neither are specific for the mutated FIP-coronavirus.
Although it had been claimed that 7B protein was Lymphocytic, plasmocytic cholangiohepatitis occa-
specific for FIP strains, subsequent studies have shown sionally produces a high protein abdominal fluid simi-
that it is not present in some FIP strains, and that non- lar to that of effusive FIP.
FIP coronavirus may have an active 7B component.
Currently there is no serological test that is specific for
FIP-coronavirus. Treatment
● 30% of household pet cats and 80–90% of cat-
FIP is a fatal disease with no known treatments. The
tery cats carry coronavirus and have positive
therapies listed below have been used in an attempt to
coronavirus titers.
slow progression and/or to improve quality of life.
● Although a few cats with effusive FIP have a nega-
tive coronavirus titer, cats with a negative coron- Glucocorticoids at immunosuppressive doses (pred-
avirus titer are unlikely to have FIP. nisolone 4 mg/kg/day).
2
Reverse transcriptase, polymerase chain reaction Cyclophosphamide (200–300 mg/m q 2–3 weeks or
(PCR) is available for detection of viral RNA. Positive 2.2 mg/kg daily for 4 days each week) or chlorambucil
2
results correlate with a diagnosis of FIP when fluid (20 mg/m q 2–3 weeks).