Signs of septic arthritis in dogs

If your dog is suddenly lame with a hot, swollen joint, especially with a fever, see your vet the same day.

Septic arthritis is a painful infection inside a joint. It needs prompt veterinary treatment, because infection can damage the joint quickly.

What is septic arthritis?

Arthritis means inflammation of a joint. Septic arthritis is a form of arthritis caused by infection. Germs, usually bacteria and occasionally fungi, get into the joint and cause inflammation, pain and swelling. Without treatment, the infection can damage the cartilage that lines the joint.

This is different from osteoarthritis, the common "wear and tear" arthritis seen in many older dogs, which is not caused by infection.

How does infection get into a joint?

Infection usually reaches a joint in one of three ways:

• Through a wound. A bite from another animal, or a deep cut or puncture near a joint, can carry germs into it.
• After joint surgery or injections. Occasionally, infection follows an operation on a joint or an injection into it.
• Through the blood. Infection elsewhere in the body can spread through the bloodstream and settle in a joint.

Sometimes no clear cause is found.

Signs to watch for

Signs often come on fairly suddenly and usually affect one joint. They include:

• lameness, or not wanting to put weight on a leg;
• a swollen joint;
• a joint that feels hot or is painful to touch;
• not wanting to bend or move the joint;
• fever;
• lethargy;
• loss of appetite.

Any sudden lameness with a hot, swollen joint is a reason to see your vet the same day, not to wait and see.

How your vet will investigate

Your vet will ask when the signs started and about any recent wounds, bites, surgery or injections. They will then examine your dog.

Tests your vet may suggest include:

• blood tests;
• a urine test;
• X-rays of the affected joint;
• taking a sample of fluid from the joint to look for infection;
• arthroscopy, where a small camera is used to look inside the joint.

Treatment

Treatment depends on the cause and how severe the infection is. It usually includes medication to fight the infection and to control pain. Some dogs need to stay in the veterinary hospital so the joint can be flushed out or treated surgically.

How well a dog recovers depends on how quickly the infection is treated, how much the joint has been affected, and the dog's general health. Your vet will usually want to see your dog for check-ups to make sure the infection has cleared.

Caring for your dog at home

• Give any medication exactly as your vet prescribes, and finish the full course.
• Follow your vet's advice on rest, pain relief and any home care.
• Keep exercise to what your vet recommends, and avoid long or energetic walks until they say it is safe.
• Never give your dog painkillers or other medicines meant for people.
• Contact your vet if the lameness or swelling gets worse, or your dog seems unwell.