Page 936 - Clinical Small Animal Internal Medicine

874 Section 9 Infectious Disease

weight loss, pale mucous membranes, fever of unknown mately 60% of cats with FIP. The hyperglobulinemia is
VetBooks.ir origin, and uveitis. Commonly, a distinction is made usually polyclonal, although monoclonal gammopathy
may occur. Hypoalbuminemia can be present, possibly
between the wet (effusive) and dry (noneffusive) forms of
FIP, but they are not mutually exclusive. In the wet form,
nephropathy or enteropathy, or due to decreased pro-
abdominal distension due to the accumulation of exuda- due to hepatic insufficiency, vasculitis, protein‐losing
tive fluid is the most common presentation. A fluid wave duction associated with the acute phase reaction. A nor-
on physical examination may be evident, but some cases mal or elevated serum albumin:globulin ratio can help
will have less fluid accumulation, only detectable by rule out FIP as it is often decreased in affected cats.
abdominal ultrasound. Pleural effusion with secondary
dyspnea, tachypnea, and muffled heart sounds may be Acute Phase Proteins
present, whereas pericardial effusion is uncommon.
Common signs of the dry form are mild and intermit- Acute phase proteins are a class of proteins whose plasma
tent fever, decreased appetite, weight loss, stunted concentrations increase or decrease in response to
growth, depression, pale or yellow mucous membranes, inflammatory disorders. Levels of alpha‐1‐acid glyco-
and palpable abdominal organ enlargement. Clinical protein, an acute phase protein, of >1.5 g/L in plasma or
signs may also reflect dysfunction of affected organs. effusions are suggestive of FIP in cats with compatible
Pyogranulomatous lesions may develop in one or more clinical signs.
abdominal organs. If granuloma formation involves the
intestine, constipation, diarrhea, or vomiting may be the Effusion Fluid
major clinical signs observed. Enlarged mesenteric lymph
nodes and palpable nodular irregularities on the surface Effusions from the abdomen or pleural space are typically
of kidneys and liver may also be present on physical clear, straw‐colored, or viscous due to the high protein
examination. Uveitis is the most common ocular abnor- content. Rivalta’s test can differentiate transudate from
mality documented in FIP cases, but other ocular lesions exudate (www.abcdcatsvets.org/). A test tube is filled
such as conjunctivitis, corneal precipitates, iritis, cuffing with 7–8 mL of distilled water and one drop of acetic acid
of the retinal vasculature and retinal detachment may be (98%) and mixed thoroughly. One drop of the effusion
present. Neurologic signs can also be seen with FIP, the fluid is layered onto the surface of this solution. Diffusion
most common being behavioral changes, ataxia, central of the drop indicates a negative result, and therefore most
vestibular signs, hyperesthesia, nystagmus, and seizures. likely indicates a FIP‐negative animal. If the drop floats
Any part of the CNS can become affected in this disease. slowly down in a drop or jellyfish‐like shape or stays at
the surface, the Rivalta’s test is positive and the fluid may
be considered an exudate. Fluid analysis is usually high
Diagnosis protein (>3.5 g/dL) with a low nucleated cell count con-
sisting primarily of neutrophils and macrophages,
With the exception of histopathology and immunostain- although findings may be variable. An effusion
ing, no single laboratory test can definitely diagnose FIP. albumin:globulin ratio below 0.4 is suggestive of FIP.
Therefore, the diagnosis of FIP continues to be based
primarily on the combination of history of risk factors, Serology
signalment, clinical abnormalities, and laboratory find-
ings. The diagnostic process starts with a good history Although different assays that detect antibodies directed
and comprehensive physical examination. against FCoV are commercially available, it is not possi-
ble to distinguish between exposure to FECV and FIPV
infection. High antibody titer in serum does not always
Complete Blood Test and Biochemical Profile
correlate with occurrence of FIP, and titers may be nega-
Abnormalities may include anemia, which is usually tive in cats with FIP. It has been suggested that many cats
nonregenerative. Evidence of hemolysis, with or without without FIP and who would never develop FIP have been
evidence of immune‐mediated destruction, may be pre- needlessly euthanized due to a positive FCoV titer.
sent. Lymphopenia, neutrophilia, sometimes with a left
shift and toxic change, and thrombocytopenia also occur. Reverse Transcriptase Polymerase
Hyperbilirubinemia and elevated aspartate aminotrans- Chain Reaction
ferase (AST) and alanine aminotransferase (ALT) may
also occur. Hyperproteinemia (>8.0 mg/dL) due to hyper- Reverse transcriptase polymerase chain reaction (RT‐
globulinemia is a consistent finding, present in approxi- PCR) assays can detect FCoV in a variety of samples