Page 539 - Problem-Based Feline Medicine

24 – THE ANEMIC CAT 531

Antibody-coated red blood cells are removed by the tive cats suggesting it is more sensitive. Some healthy
reticuloendothelial system, and intravascular lysis is cats are PCR positive and so the predictive value for
unusual; Coomb’s positive test results are common. presence of disease is not 100%.
Level of parasitemia fluctuates rapidly making diagno- Macroscopic or microscopic agglutination, spherocyto-
sis difficult based on cytology. sis, or Coomb’s positive test results are suggestive.
The acute phase of disease usually develops within
3 weeks; spontaneous recovery followed by recurrence Differential diagnosis
from the chronic carrier state can occur.
Any infectious, immune-mediated, or neoplastic cause
Anemia associated with Candidatus Myco- of hemolytic anemia can look similar as a result of
plasma haemomintum is often detected in cats with signs associated with fever and anemia. Demonstration
current feline leukemia virus infection. of the organism by cytological assessment or PCR dif-
ferentiates mycoplasma-associated hemolytic anemia
In locations where feline leukemia virus is common,
from other causes.
approximately 50% of infected cats are co-infected
with the virus; co-infection with feline immunodefi-
ciency virus is rare. Treatment
Doxycycline at 10 mg/kg, PO, q 24 hours for the first
Clinical signs week and then continued q 24 hours for 2 weeks. If the

Infection is most common in male cats less than 3 cat will tolerate treatment, a total of 4 weeks of treat-
years of age, and occurs most often in the spring. ment may result in more cats becoming PCR negative.
Cats are usually presented for depression, lethargy While tetracycline at 22 mg/kg, PO q 8 hours can be
and anorexia. effective it is no longer recommended since doxy-
cycline is superior.
Pale mucous membranes are a common physical exami-
nation abnormality. Fever and icterus are also common. Enrofloxacin at 5–10 mg/kg, PO, q 12–24 hours for
2–3 weeks may be effective in cats that are intolerant of
Splenomegaly occurs in some from extramedullary tetracyclines. Doses over 5.5 mg/kg may be associated
hematopoiesis and immune stimulation. with retinal toxicity and blindness in a small percentage
Fleas or flea dirt may or may not be noted. of cats.
Chronic infection may lead to recurrent hemolytic For cats that do not tolerate or are resistant to tetracyclines
anemia or intermittent fever, depression and anorexia and enrofloxacin, imidocarb diproprionate at 5 mg/kg,
without hemolytic anemia. IM or SQ, q 2 weeks, for 2–4 injections can be used.
Chloramphenicol at 15 mg/kg, PO, q 12 hours for 3
Diagnosis weeks has been used but not studied experimentally;
this drug also has been associated with bone marrow
Diagnosis is based on cytological demonstration of
suppression.
the organism on the surface of RBC. However, the
organism may be difficult to find even though clinical Prednisolone at 1–2 mg/kg, PO, q 12 hours should be
signs are present, and at least 50% of cats are falsely used for at least the first week of therapy because of the
negative on cytological examination. immune-mediated pathogenesis.
The organism may dislodge from the surface of RBCs Treatment lessens clinical signs of disease but does not
placed in EDTA in cytologically negative suspect cats. resolve infection in many cats.
In suspect cats, repeat cytological assessment using
While there is no PCV that alone indicates when to
smears made from blood without anti-coagulants.
transfuse, whole blood transfusions are generally indi-
Polymerase chain reaction (PCR) is available com- cated if the PCV is dropping rapidly and heart and res-
mercially. PCR is positive in some cytologically nega- piration rates are elevated at rest.