Septic Arthritis (in other terms as Bacterial Arthritis or Infectious Arthritis) is an infection in the fluid and tissues of joint cavity most commonly caused by bacteria. It is considered a dangerous form of acute arthritis in dogs because just like other bacterial infections, the bacterial can get into dog's bloodstream and carry an infecting organism into other parts of the body. Bacteria can cause infectious joint disease by tick-borne diseases such as Rocky Mountain spotted fever and by fungal infection. On Septic Arthritis, the primary bacterial sources, based on clinical search and studies, were associated with abscesses, bite wounds, enteritis, dermatitis, cystitis and/or endometritis after birth.

Septic arthritis normally only affects a single joint and the condition results in swelling, fever, heat, and pain in the joint. With septic arthritis, the dog is likely to stop eating and become depressed. Risk factors for septic arthritis are joint problems, rheumatoid arthritis, high infection risk, and a weak immune system. Septic arthritis is commonly spread hematogenously with predisposing factors being intravenous drug usage, in-dwelling catheters present as well as underlying immuno-compromised states. Bacteria are carried by the bloodstream from an infectious focus or are introduced by a skin lesion that penetrates the joint. Septic Arthritis most commonly occurred after surgeries of the stifle joints of dogs. The joint cavity is usually a sterile space, with synovial fluid and cellular matter including a few white blood cells. Some diagnosis was based on clinical signs, joint fluid analysis, radiography, microbiology and/or response to treatment. Chronic lameness was the most common problem at presentation. Analysis of joint fluid invariably revealed large number of nucleated cells, which consisted primarily of neutrophils. Bacterial septic arthritis may often be mild and manifest as chronic lameness. Analysis of joint fluid will detect an inflammatory arthropathy but the presence of toxic neutrophils should not be relied on as an indicator of sepsis. Culture of infected joint fluid is likely to be successful if antimicrobials are not given prior to collection and if the sample is inoculated into enrichment broth. Treatment should involve antimicrobial drugs, open-joint lavage and removal of joint prostheses if the infection is associated with previous surgery.

Septic arthritis might be difficult to diagnose due to nonspecific clinical signs and radiological findings in early stage of the disease. An early diagnosis is important for achieving favorable prognosis. Diagnosis of septic arthritis was confirmed by physical and orthopaedic examinations, evaluation of radiographs and synovial fluid analysis including leukocyte and neutrophil counts, cytological examination and bacterial culture. Bacteria is one of the most common causes of infective arthritis in dogs. However, bacterial arthritis in dogs can resemble many other arthropathies and attempts to achieve a definitive diagnosis by culture of the offending organism are not always successful.

The treatment of Septic Arthritis involves determining the type of microorganism involved and its antibiotic sensitivity. Antibiotics are usually administered for a minimum of a month and analgesics (pain relief medications) are necessary to combat pain and inflammation. Other major treatment involves antimicrobial drugs, while there many other cases the dog received antimicrobial drugs and with combination of surgical procedures such as joint lavage and sometimes removable of non-absorbent suture material, arthrodesis and amputation. The surgical treatment for septic arthritis (infectious arthritis) includes removal of joint fluid. To examine white blood cells and bacteria blood tests are performed.