Causative & risk factors
Septic arthritis is caused due to infection with bacteria, viruses or fungi. The commonly responsible bacterial organisms include Staphylococcus aureus or Haemophilus influenza; viral organisms include Hepatitis A, B, and C, parvovirus B19, herpes viruses or HIV and fungal organisms include Histoplasma, Coccidioides, Blastomyces etc.
Some people are more prone to developing septic arthritis due to the presence of certain risk factors. Suffering from another form of arthritis (e.g. rheumatoid arthritis) or having osteomyelitis close to a joint put an individual at a higher risk of developing septic arthritis. History of recent injury, injections or surgery to any joint; or having an artificial hip, knee or other prosthesis is also risk factors for septic arthritis. Lowered immunity arising from any cause can also increase the probability of developing septic arthritis.
Clinical presentation
The patient presents pain and stiffness at the site of the affected joint. He also has fever (with or without chills). Examination reveals redness, warmth and swelling over the affected joint structure.
Untreated septic arthritis can lead to complications like septicemia and destruction of the joint structure.
Investigations
Initially a thorough patient history is noted followed by physical examination of the site of pain. Imaging studies such as X-ray, CT scan or MRI of the affected joint are done to check for joint damage.
Arthrocentesis: In this procedure, a fluid sample is taken from the joint via a needle (aspirated) and analyzed for cell count, examination of crystals under the microscope, gram stain, and culture. Blood tests such as Complete blood count and tests for inflammatory markers (CRP, ESR) may be performed.
Arthroscopy is a diagnostic as well as therapeutic procedure in which an endoscope is introduced into the joint space to examine as well as treat the underlying damage.
Treatment
Supportive therapy such as rest, hot fomentation, limb elevation and splinting are suggested to help relieve the pain. Antibiotics or antifungal drugs are prescribed depending upon the infective organism. Anti-inflammatory drugs are given to reduce the inflammation and pain. Arthroscopy is performed to drain the synovial fluid from the infected joint. Sometimes open joint surgery may be necessary to accomplish drainage of the infected fluid.
Physical therapy may be necessary to help regain joint function.
Recent updates
A research study has suggested that patients of Rheumatoid arthritis who are treated with anti-TNF (tumor necrosis factor) therapy double the patient’s risk of developing septic arthritis.
Another study suggested that a combination of anti-microbial and corticosteroid drugs has a beneficial effect in cases of septic arthritis in children.
