Septic arthritis in cats: how long to give antibiotics
3-year-old male cat with septic arthritis of the carpus after a bite, treated with joint lavage and amoxicillin-clavulanate (Pasteurella multocida susceptible on culture). After 10 days he bears weight normally and the joint is no longer warm. The owner asks whether he can stop the antibiotic.
What do you recommend now?
chevron_right Show answer and explanation
A. Continue the antibiotic to complete about 4–6 weeks (at least 2 weeks beyond clinical resolution), with controlled mobilisation and rechecks
Correct. Joint infections require prolonged treatment because bacteria persist in the synovium and cartilage even after signs resolve. Early controlled mobilisation nourishes cartilage and prevents stiffness. Warn that secondary osteoarthritis may develop.
B. Stop the antibiotic now, since the cat is clinically cured
Ten days is insufficient for a joint infection: early withdrawal favours relapse and further cartilage destruction.
C. Replace the antibiotic with prednisolone to control residual inflammation
Corticosteroids in a recently infected joint favour relapse of infection. Residual inflammation is controlled, if needed, with an NSAID and rehabilitation.
D. Immobilise the carpus in a rigid splint for 6 weeks to protect the cartilage
Prolonged immobilisation causes stiffness, cartilage atrophy and muscle loss; cartilage is nourished by synovial fluid through movement.
lightbulb Key takeaway
Adjust the antibiotic to culture results and do not stop it because of clinical improvement. If lameness returns or the joint swells again, repeat arthrocentesis: there may be relapse, a foreign body or osteomyelitis.
Test yourself with 10 random questions
Musculoskeletal system · 100 questions, a different test every time
Related questions
Updated: October 31, 2026 · Educational content for veterinary professionals. It does not replace current clinical guidelines or the judgement of the attending veterinarian.