Page 1452 - Small Animal Internal Medicine, 6th Edition

1424 PART XIII Hematology

least useful (≈4% each); cytology and histopathology were cause of the fever cannot be determined in 10% to 25% of
the advanced diagnostic methods that provided the most small animals.
VetBooks.ir answers (56%). DIAGNOSTIC APPROACH TO THE
Thus, in contrast to what was previously thought, infec-
PATIENT WITH FEVER OF
tious diseases do not appear to be the most common cause
of FUO in dogs (and likely cats). Instead, inflammatory non- UNDETERMINED ORIGIN
infectious disorders, including immune-mediated diseases,
represent most cases with FUO that are eventually diagnosed A dog or cat with FUO should be evaluated in a systematic
(Table 90.1). Interestingly, despite aggressive evaluation, the fashion. In general, a three-stage approach is used at our

TABLE 90.1

Causes of Fever of Undetermined Origin in Dogs and Cats

CAUSE SPECIES AFFECTED CAUSE SPECIES AFFECTED
Infectious Immune-Mediated
Bacterial
Polyarthritis D, C
Bacterial endocarditis D Vasculitis D
Brucellosis D Meningitis D
Tuberculosis D, C Systemic lupus erythematosus D, C
Mycoplasmosis D, C Immune hemolytic anemia D, C
Plague C Steroid-responsive fever D, C
Borreliosis D Steroid-responsive neutropenia D, C
Bartonellosis D, C
Suppurative infection (e.g., abscess D, C Neoplastic
[liver, pancreas], stump pyometra, Acute leukemia D, C
prostatitis, discospondylitis, Chronic leukemia D, C
pyelonephritis, peritonitis, Lymphoma D, C
pyothorax, septic arthritis)
Malignant histiocytosis D
Rickettsial Multiple myeloma D, C
Ehrlichiosis, anaplasmosis, Rocky D, C Necrotic solid tumors D, C
Mountain spotted fever, salmon
poisoning Miscellaneous
Metabolic bone disorders D
Mycotic
Drug induced (tetracycline, D, C
Histoplasmosis D, C penicillins, sulfa)
Blastomycosis D, C Tissue necrosis D, C
Coccidioidomycosis D
Hyperthyroidism D, C
Viral Idiopathic D, C
Feline infectious peritonitis C
Feline leukemia virus infection C
Feline immunodeficiency virus C
infection
Circovirus D

Protozoal
Babesiosis D
Hepatozoonosis D
Cytauxzoonosis C
Chagas disease D
Leishmaniasis D, C

C, Cat; D, dog.