Page 508 - Problem-Based Feline Medicine

500 PART 7 SICK CAT WITH SPECIFIC SIGNS

whole blood, platelet-rich plasma, or fresh-frozen processes, e.g. neoplasia, bone marrow failure with
plasma (which contains functional platelet particles), griseofulvin therapy.
10–20 ml/kg. Bleeding due to thrombocytopenia – FIV infection in-itself does not commonly cause
may also be treated with platelet concentrate, 1–2 severe megakaryocytic hypoplasia.
units/cat. – FIV infection in-itself does not appear to cause
● Transfusion is recommended before biopsy of platelet function defects.
9
internal organs if the platelet count is < 50 × 10 /L ● Prolongation of aPTT. The mechanism is not
(50,000/dl). known, but it is not due to specific factor deficien-
cies, DIC, or a circulating inhibitor.
Treat infections and neoplasia.
● Prolongation of TT. The mechanism is not known,
Recombinant human interferon-α, 1 unit/cat PO q but it is not due to hypofibrinogenemia or dysfib-
24 h may ameliorate myelosuppression. rinogenemia.
● DIC secondary to infections and neoplasia.
Bone marrow transplantation for megakaryocytic
hypoplasia may be considered if available.
Clinical signs

Clinical bleeding is uncommon.
Prognosis
Severe thrombocytopenia may cause bleeding typical
Prognosis for severe FeLV-induced megakaryocytic
of platelet disorders, e.g. petechiation, epistaxis,
hypoplasia is poor.
melena, prolonged bleeding after venepuncture.
Long-term prognosis with other hemostatic defects
Prolongation of the aPTT and TT do not result in
is determined by the FeLV-associated underlying
abnormal bleeding.
disease.
Diagnosis
FELINE IMMUNODEFICIENCY VIRUS (FIV)
INFECTION** FIV antibody test (ELISA, FA, western blot).
● Antibody is usually detectable within 2 months of
Classical signs infection, but may take up to 6 months, therefore a
negative test should be repeated if FIV is being con-
● Lethargy, inappetence, weight loss,
sidered in the differential diagnoses of a cat with
unkempt haircoat, fever, generalized
thrombocytopenia.
lymphadenopathy, gingivitis, diarrhea,
● PCR test for viral DNA. It should be noted that
dermatitis, recurrent upper respiratory
PCR testing has not been standardized and is
infections, opportunistic infections,
more likely to give false-positive results than
neurologic signs, uveitis.
antibody tests if the laboratory does not main-
● Various hemostatic abnormalities may
tain the highest standards of quality control.
occur but are usually subclinical.
Neutropenia and lymphopenia are common con-
See main reference on page 339 (The Thin, Inappetent current hematologic abnormalities in symptomatic
Cat). cats.
Hemostatic testing may reveal the following abnormal-
ities due to FIV infection: low to normal platelet count,
Pathogenesis
normal BMBT unless thrombocytopenic, shortened to
The following hemostatic defects may occur with normal PT, normal to prolonged ACT and aPTT, nor-
FIV infection: mal to prolonged TT and normal to increased fibrino-
● Thrombocytopenia. This may be due to the pri- gen. In addition, prolonged PT, ACT and aPTT and
mary infection or secondary to other disease hypofibrinogenemia may occur if DIC is present.