Page 90 - Problem-Based Feline Medicine

82 PART 2 CAT WITH LOWER RESPIRATORY TRACT OR CARDIAC SIGNS

Thoracocentesis or abdominocentesis and examina- effusive (humoral, beta cell mediated) and granuloma-
tion of the fluid are very valuable. tous (cell-mediated, T-cell response) forms of the dis-
ease, but generally have a very poor outcome in almost
The high protein (50–120 g/L) and fibrin content of
all cases. For a more thorough discussion, see page
the fluid makes it thick, viscous and straw-colored. Cell
458, The Cat With Abdominal Distention or
9
count is moderate (10 × 10 /L), and consists predomi-
Abdominal Fluid.
nantly of non-degenerative neutrophils.
● For effusive FIP, several strategies have been advo-
Electrophoretic separation of the proteins within the cated, including:
fluid may be helpful. – Corticosteroids: prednisone 2–4 mg/kg/day PO.
● Fluid with gamma globulins > 32% has a high pos- – Cytotoxic drugs: cyclophosphamide 2.2
itive predictive value for FIP. mg/kg/day PO 4 days each week, or 50 mg/m 2
2
● Fluids with protein comprised of > 48% albumin PO q 48 hours, or melphalan 2 mg/m PO q 48
2
had a very high negative predictive value for ruling h, or chlorambucil 1.5 mg/m PO q 24 hours.
out FIP. – Antiviral drugs: ribavirin 5 mg/kg IV q 24 h.
● Histopathology of liver, kidney or other abdom- Ribavirin is very toxic to cats, mainly myelosup-
inal tissue with inflammation is diagnostic. pressive. It has not been shown to substantially
improve the longevity, although a slight increase
in survival time (10 days) with fewer clinical
Differential diagnosis
signs has been documented. Ribavirin can be
There are few other differential diagnoses for combined with interferon therapy. Low-dose
hydrothorax with a clear or straw-colored, highly pro- oral human interferon-alpha (Roferon) 30
teinaceous fluid. Other forms of pleural effusion with an IU/day PO has been advocated.
exudative fluid are usually turbid, such as pyothorax. – NB: in high risk, systemically ill cats, omitting
● Pyothorax may have systemic clinical signs and the cytotoxic and antiviral agents is recom-
effusion fluid that resembles FIP. FIP fluid has high mended.
protein content (50–120 g/L) with low to moderate
Ancillary treatment consists of using the serotonin
9
cellularity (10 × 10 /L), and predominantly non-
antagonist cyproheptadine (1–2 mg PO q 12 hours) for
degenerative neutrophils, while pyothorax fluid has
appetite stimulation. Antibiotics have been used, espe-
moderately high protein levels (30–70 g/L), and
extremely high nucleated cell counts (5–300 × cially with neutropenia and fever, but with no data to
support efficacy. Amphotericin B has been shown to
9
10 /L), which are mostly degenerative septic neu-
have in vitro antiviral effects against FIP, but its nephro-
trophils. Electrophoresis and bacterial culture of the
toxicity limits its use in cats.
fluid may help separate these entities. FIP fluid has
high gamma globulin and is sterile, where pyothorax
Prognosis
fluid has a balanced albumin/globulin ratio, and is a
septic exudate, based on Gram stain or culture Long-term prognosis for effusive FIP is extremely
results. poor. Average survival from onset of clinical signs is
Pericardial effusion may present with ascites and 5–7 weeks, although some stronger “healthier” individ-
pleural effusion. uals may have a more insidious disease course, and
may survive for 6–8 months.
Treatment
Prevention
Emergency thoracocentesis should be performed in
Management strategies
cats with severe respiratory distress (see section on
● One study showed kittens raised in catteries with
Pleural effusions, this chapter).
all other cats or isolated from other cats except
Medical management queens had 30–50% positive titers for FIPV, and
● Management strategies for FIP take advantage of 1–2% death rate from clinical FIP. However, kit-
the different immunopathogenic mechanisms of the tens raised in a cattery, that were weaned and