How Are Bone and Joint Infections Diagnosed?
The diagnosis of osteomyelitis is with a positive culture of bacteria from a bone biopsy and microscopic findings of inflammation.Alternately, this step may not be necessary in patients with imaging (X-Ray) results that are typical of osteomyelitis when blood cultures are positive.
In diabetics or those with deep ulcers, probing a lesion for underlying bone can help identify associated osteomyelitis.
Treatment of bacterial infections depend on identification of the infecting organism. Bone biopsy is used to culture which organism(s) are responsible and to test sensitivity to an array of antibiotic choices: this drives the therapy.
Other causes of the signs and symptoms of osteomyelitis must be ruled out, These include:
● Tissue infection: Separable from bone infection by the use of a bone probe.
● Avascular bone necrosis (malignancy, sickle cell anemia, diabetes).
● Gout: Detection of uric acid crystals in joint fluid.
● Fracture: Associated with prior trauma and positive findings on radiological imaging.
● Bursitis: Distinguishable from osteomyelitis by bursa aspiration.
● Synovitis: Common in osteo- and rheumatoid arthritis.
Bacteria in synovial fluid confirms the diagnosis for septic arthritis:
● Synovial fluid aspiration: for Gram stain and culture, white blood cell count, and identifying any crystals. Aspiration can be guided by CT, ultrasound, or fluoroscopy.
● Concurrent physical findings of pain: especially with joint mobility.