7th Annual Gulf-Atlantic Veterinary Conference
The term fever of unknown origin (FUO) is used liberally in veterinary medicine and is usually defined as a greater than 103.5-104°F (39.7–40°C) body temperature of no specified duration. The fever is usually persistent and will not resolve spontaneously. On initial evaluation, it is important to differentiate whether the body temperature increase is due to true fever or nonfebrile hyperthermia. Fever may result from any inflammatory, infectious, immune-mediated or neoplastic disease. The diagnostic approach involves a detailed history and thorough physical examination with abnormal findings including, but not limited to, peripheral lymphadenopathy, joint effusion, spinal/paraspinal pain, a low-grade cough with increased bronchovesicular sounds on thoracic auscultation, prostatomegaly, swollen testicles in intact dogs, resistance to manipulation of the neck and head, red and swollen gums, or abdominal discomfort on palpation. Diagnostic testing is usually onerous, somewhat laborious and is beyond the financial means of some owners when there are no immediate answers as to the cause of the fever. Diagnostic tests are often targeted at excluding common causes of fever initially with more specialized tests being reserved once these higher-yield differentials have been ruled out. In this lecture, an overview of FUO will be presented as well as a practical workup for the presentation.