Page 464 - Problem-Based Feline Medicine

456 PART 7 SICK CAT WITH SPECIFIC SIGNS

was first detectable 25–29 days prior to parturition, lent FIP strains arise from mutations in the avirulent
and the vertebral column detectable by day 22–27 (enteric) strains during replication of the latter. Both
prior to parturition. The pattern of progressive min- type I (genuine) FCoV and type II FCoV (which result
eralization was used to accurately predict day of from recombination between FCoV and canine coron-
parturition. avirus) can give rise to FIP strains.
The virus initially replicates in epithelial cells of the
Differential diagnosis pharynx, respiratory system and intestinal tract.
Cats with uncomplicated pregnancies are healthy, and Antibodies are produced, which fail to eliminate the
as such the main differential diagnosis is obesity. virus and facilitate its uptake by macrophages, where
However, obese cats are more often neutered, and the virus further replicates.
obese cats also have evidence of increased subcuta-
Macrophages migrate in the blood to venules of various
neous inguinal fat. Palpation of an enlarged uterus is
tissues, e.g. the serosa of the abdomen. The macrophages
usually possible in pregnant cats, and palpation find-
exit the venules, and virus replication continues.
ings can be confirmed by imaging.
Antigen–antibody complexes form around the
If a sick cat with abdominal distention with an venules, attracting neutrophils. The result is a pyo-
unknown pregnancy is presented for examination, all granulomatous vasculitis, resulting in effusion.
other causes for abdominal distention should be con-
FIP is more common in cats infected with feline
sidered. If the only cause of abdominal distention found
leukemia virus (FeLV) in areas where FeLV is fre-
during work-up appears to be an enlarged uterus, then
quent.
acute metritis or spontaneous abortion should be
considered, as well as an unrelated disorder complicat-
ing pregnancy. Clinical signs
Most common in cats 3 months to 3 years old. There
Treatment may also be an increased prevalence in geriatric cats.

Ovariohysterectomy if the pregnancy is unwanted. FIP occurs in two main forms: wet (effusive) and dry.
Non-specific signs (depression, anorexia, weight
loss, fever) are common in both forms.
Prognosis
In wet FIP, pericardial, pleural and/or peritoneal
Good – dystocia is uncommon in cats.
effusions occur.
● Initially abdominal organs, especially the intes-
Prevention tines, may not feel as distinct as usual.
● Later, as fluid accumulates, marked painless dis-
Ovariohysterectomy; isolate from toms during heat.
tention of the abdomen occurs.
In dry FIP, signs are referable to the organ involved.
FELINE INFECTIOUS PERITONITIS (FIP)***
● FIP may cause chronic hepatitis, which could
result in abdominal distention from hepatomegaly
Classical signs
and ascites from portal hypertension.
● Depression, anorexia, weight loss, fever, ● Massive mesenteric lymphadenopathy has also
pleural or peritoneal effusion. been reported.

Pathogenesis Diagnosis
FIP is caused by strains of feline coronavirus (FCoV). No routinely performed test has 100% sensitivity or
These virulent stains have the ability to replicate in specificity, and diagnosis always relies on a combina-
macrophages as well as in epithelial cells. The viru- tion of clinical signs and laboratory test results.