Page 1454 - Small Animal Internal Medicine, 6th Edition

1426 PART XIII Hematology

TABLE 90.2 arrive at a definitive diagnosis. In these patients, changes in
the CBC are usually the only clinicopathologic abnormality
VetBooks.ir Hematologic Changes in Dogs and Cats With Fever of (see Table 90.2), that is, results of bacterial and fungal cul-
tures, serologic tests, PCR assays, imaging studies, and FNAs
Undetermined Origin
HEMATOLOGIC are negative or normal. If the patient has already been treated
with a broad-spectrum bactericidal antibiotic, a therapeu-
CHANGE CAUSE OF THE FEVER tic trial of immunosuppressive doses of corticosteroids is
warranted. However, before instituting immunosuppressive
Regenerative Immune-mediated disease,
anemia hemoparasites (e.g., treatment, the owners should be informed of the potential
Mycoplasma, Babesia), drugs consequences of this approach, mainly that a dog or cat
Nonregenerative Infection, chronic inflammation, with an undiagnosed infectious disease may die as a result
anemia immune-mediated disease, tissue of systemic dissemination of the organism after the start
necrosis, malignancy, of treatment. Dogs and cats undergoing a therapeutic trial
endocarditis of corticosteroids should be kept in the hospital and moni-
Neutrophilia with Infection, immune-mediated tored frequently for worsening of clinical signs, in which
left shift disease, tissue necrosis, case steroid therapy should be discontinued. In patients with
malignancy, endocarditis immune-mediated (or steroid-responsive) FUO, the pyrexia
Neutropenia Leukemia, immune-mediated and clinical signs usually resolve within 24 to 48 hours of
disease, pyogenic infection, the start of treatment.
bone marrow infiltrative disease, If no response to corticosteroids is observed, two courses
drugs of action remain. In one, the patient can be released and
Monocytosis Infection, immune-mediated given antipyretic drugs, such as aspirin (10-25 mg/kg orally
disease, tissue necrosis, [PO] q12h in dogs, and 10 mg/kg PO q72h in cats) or other
lymphoma, endocarditis, nonsteroidal antiinflammatory drugs (NSAIDs) and then
histiocytosis returned to the clinic for a complete reevaluation in 1 to 2
Lymphocytosis Ehrlichiosis, anaplasmosis, Chagas weeks. Antipyretics should be used with caution, however,
disease, leishmaniasis, chronic because fever is a protective mechanism, and lowering the
lymphocytic leukemia body temperature may be detrimental in an animal with an
Eosinophilia Hypereosinophilic syndrome, infectious disease. Also of note is that some NSAIDs have
eosinophilic inflammation, ulcerogenic effects, can cause cytopenias, and may result in
lymphoma tubular nephropathy if the patient becomes dehydrated or
Thrombocytopenia Rickettsiae, leukemia, lymphoma, receives other nephrotoxic drugs. The second course of
drugs, immune-mediated disease action is to continue the trial of antibiotics by using a com-
Thrombocytosis Infections (chronic), immune- bination of bactericidal drugs (e.g., ampicillin and enrofloxa-
mediated disease cin) for a minimum of 5 to 7 days.

Suggested Readings
polyarthritis may be the only manifestation of a widespread
immune-mediated or infectious disorder (e.g., anaplasmo- Battersby IA, et al. Retrospective study of fever in dogs: laboratory
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abdominal ultrasonography should be performed to search Chervier C, et al. Causes, diagnostic signs, and the utility of
for a silent septic focus. In dogs and cats with neurologic investigations of fever in dogs: 50 cases. Can Vet J. 2012;53:
signs associated with fever, a cerebrospinal fluid tap should 525.
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nosis has still not been reached, bone marrow aspirates for 574.
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practice. Finally, if a definitive diagnosis is ultimately not dogs. Compend Contin Educ Vet. 2009;31:14.
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can be initiated. Pract. 2016;July/August:30–35.
Harkin KR. Uncovering the Cause of Fever in Cats. Today’s Vet
Treatment
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If a definitive diagnosis is obtained, a specific treatment Scott-Moncrieff JC, et al. Systemic necrotizing vasculitis in nine
should be initiated. The problem arises if the clinician cannot young beagles. J Am Vet Med Assoc. 1992;201:1553.