Acute septic arthritis in infancy and childhood

Summary 1. Acute septic arthritis in childhood and infancy is an uncommon condition. Early diagnosis and early introduction of adequate treatment can prevent the crippling sequelae, especially when the hip joint of an infant is involved. 2. Successful treatment of acute septic arthritis demands adherence to two fundamental principles: (i) the antimicrobial agent used must achieve effective concentrations within the joint: (ii) the purulent contents of the infected joint must be resorbed by the host or removed by the medical attendant. 3. Effective concentrations of an antibiotic are present in an infected joint during systemic therapy and this obviates the need for local installation of antibiotics into a synovial space with attendant risks of destruction of articular cartilage and persisting ‘synovitis’. 4. Blood cultures and arthrocentesis should be performed before antibiotics are administered in all cases of suspected septic arthritis. 5. Antibiotics to be initially administered, before identification of causative organisms and antibiotic sensitivity, can be chosen on a “best guess' principle. 6. In infants under the age of 6 months a wide range of organisms may be the cause, and broad spectrum bacteriocidal cover is required. Cloxacillin or Methicillin and Kanamycin have been recommended. Between the age of 6 months and 2 years the most common causative organisms is Haemophilias influenzae , and Ampicillin is the drug of choice. Over the age of 4 years, staphylococci are the most common cause and should be treated with Methicillin or Cloxacillin. 7. Microscopic observation of a Gram‐stained smear from an initial aspirate may help in choosing the most appropriate antibiotic. If no organisms are seen or grown on culture, the combination of Methicillin or Cloxacillin together with Ampicillin appears most appropriate. 8. The incidence of complications is directly related to the duration between onset of symptoms and introduction of effective treatment. 9. Septic arthritis of the hip, particularly in the infant, should be treated by antibiotics and surgical incision and drainage of the joint in all cases. 10. In arthritis of joints other than the hip, there is still considerable controversy as to whether open operation and drainage should be performed in all cases, or whether this should be reserved for those which do not respond adequately to repeated arthrocentesis. The value of closed drainage with or without irrigation has not been adequately assessed. There is no place for intra‐articular installation of antibiotics. 11. It is the author's belief that no other measure will so quickly bring a septic arthritis under control than proper incision and drainage, accompanied by antibiotic therapy. 12. As the natural history of the disorder changes and micro‐organisms alter their antibiotic sensitivity, continuing studies regarding the causative organisms are mandatory. 13. Advances in therapy will come when the mechanisms of joint destruction by infection are better understood.