Shifting lameness with fever in the adult dog
4-year-old crossbreed dog with fever (39.9 °C), lethargy, a stiff "walking on eggshells" gait and shifting lameness for 10 days. Only the right stifle has mild effusion; the other joints look normal and none is clearly painful. Radiographs show no bony lesions.
What is the most appropriate next step?
chevron_right Show answer and explanation
A. Start immunosuppressive prednisolone for suspected immune-mediated polyarthritis
Immunosuppressing without confirming polyarthritis or ruling out infectious causes may worsen an infection and mask the diagnosis.
B. Arthrocentesis of the right stifle only, the only joint with effusion
A single joint does not distinguish monoarthritis from polyarthritis, which is precisely what changes the diagnosis and treatment.
C. Arthrocentesis of several joints, especially distal ones (carpi and tarsi), even if they look normal
Correct. Polyarthritis mainly affects distal joints, often without palpable effusion. Finding non-septic neutrophilic inflammation in several joints confirms it and explains the fever.
D. Empirical broad-spectrum antibiotic for suspected septic arthritis
Septic arthritis is usually monoarticular with marked pain. Fever with shifting lameness and generalised stiffness points to polyarthritis; treating blindly delays diagnosis.
lightbulb Key takeaway
With fever of unknown origin, stiffness or shifting lameness, sample at least three or four distal joints even if they are not swollen. Once polyarthritis is confirmed, look for its cause before immunosuppressing: infections (in Spain, especially leishmaniosis), endocarditis, neoplasia or drugs.
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Updated: October 31, 2026 · Educational content for veterinary professionals. It does not replace current clinical guidelines or the judgement of the attending veterinarian.