Surgery in the form of joint drainage is the gold standard management in large joints like the hip and shoulder. Without early treatment, long-term joint problems may occur, such as irreversible joint destruction and dislocation. Signs and symptoms
Children
In children septic arthritis usually affects the larger joints like the hips, knees and shoulders. The early signs and symptoms of septic arthritis in children and adolescence can be confused with limb injury. Among the signs and symptoms of septic arthritis are: acutely swollen, red, painful joint with fever. Kocher criteria have been suggested to predict the diagnosis of septic arthritis in children.Importantly, observation of active limb motion or kicking in the lower limb can provide valuable clues to septic arthritis of hip or knee. In neonates/new born and infants the hip joint is characteristically held in abduction flexion and external rotation. This position helps the infant accommodate maximum amount of septic joint fluid with the least tension possible. The tendency to have multiple joint involvements in septic arthritis of neonates and young children should be closely considered. Adults
In adults, septic arthritis most commonly causes pain, swelling and warmth at the affected joint. Therefore, those affected by septic arthritis will often refuse to use the extremity and prefer to hold the joint rigidly. Fever is also a symptom; however, it is less likely in older people. In adults the most common joint affected is the knee. Hip, shoulder, wrist and elbow joints are less commonly affected. Spine, sternoclavicular and sacroiliac joints can also be involved.
One or multiple joints can be affected at the same time.Laboratory studies such as blood cultures, white blood cell count with differential, ESR, and CRP should also be included. However, white cell count, ESR, and CRP are nonspecific and could be elevated due to infection elsewhere in the body. Serologic studies should be done if lyme disease is suspected. Blood cultures can be positive in 25 to 50% of those with septic arthritis due to spread of infection from the blood. CRP more than 20 mg/L and ESR greater than 20 mm/hour together with typical signs and symptoms of septic arthritis should prompt arthrocentesis from the affected joint for synovial fluid examination.The synovial fluid should be collected before the administration of antibiotics and should be sent for gram stain, culture, leukocyte count with differential, and crystal studies. This can include NAAT testing for N. gonorrhoeae if suspected in a sexually active person.In children, the Kocher criteria is used for diagnosis of septic arthritis. Differential diagnosis
The differential diagnosis of septic arthritis is broad and challenging. First, it has to be differentiated from acute hematogenous osteomyelitis. This is because the treatment lines of both conditions are not identical. Noteworthy, septic arthritis and acute hematogenous osteomyelitis can co-occur. Especially in the hip and shoulder joints their co-occurrence is likely and represents a diagnostic challenge. Therefore, physicians should have a high suspicion index in that regard.