Severe pain and swelling in affected joint, warmth in the area around joint, shaking chills and fever are the major symptoms of infectious or septic arthritis. This type of arthritis is caused by the bacterial infections mainly by the organisms like staphylococci, streptococci, gonococci and hemophilus influenzae. It most frequently affects the joints of knees, but can occur in the joints of hip, ankle, shoulder, elbow, fingers and wrist. This disease can cause dislocation of joints as well as blood poisoning. Hence, early diagnosis of infectious arthritis is essential to start appropriate treatment in order to avoid further complications.

When you experience the symptoms of septic arthritis, you consult your doctor. The doctor asks the questions about signs and symptoms and recent infections. This information gives a clue about the origin of infectious arthritis. The doctor confirms the diagnosis of infectious arthritis on the basis of symptoms, medical history of patient, physical examination, blood tests and analysis of synovial fluid. As this disease is associated with bacterial infections, identification of exact causative agent is very important.

Analysis of synovial fluid is one of the most significant tests for accurate diagnosis of infectious arthritis. Synovial fluid is aspirated from the infected joint through a sterile needle. This surgical procedure is known as arthrocentesis which is performed by a doctor. This fluid is analyzed for the presence of micro-organisms. The presence of crystals should not be ignored as it indicates possibility of other forms of arthritis such as gout. The culture of this fluid helps to detect particular bacteria responsible for infectious arthritis and its sensitivity and resistance to specific antibiotics.

In addition to fluid analysis, some other laboratory investigations are important for the diagnosis of infectious arthritis. Blood culture and culture of other body fluids such as urine, sputum and cerebrospinal fluid are helpful to detect the causative agent. It is also useful to rule out other causes including acute rheumatic fever, gout, Lyme disease and rheumatoid arthritis. Besides this, complete blood count (CBC) is another blood test which can help to evaluate amount of hemoglobin, red and white blood cells to monitor patient’s condition.

Although x-ray is not useful for exact diagnosis of this disease, it is helpful to rule out possibility of other causes of joint pain as well as other forms of arthritis. It can also help to evaluate joint damage. Bone scan may be beneficial for confirmation of disease.