Septic arthritis in childhood

Background: The purpose of the present study was to determine whether there was a difference between septic arthritis (SA) combined with osteomyelitis and SA alone with regard to clinical and laboratory findings, such as symptoms on admission, age, sex, joint involvement and isolated micro-organisms, and a relationship between age and joint involvement in SA. In addition, we also aimed to determine the prognostic factors in SA. Methods: The clinical and laboratory findings of 40 patients who were diagnosed with SA in our hospital were reviewed retrospectively. The diagnosis of SA was made according to the following criteria: immediate joint fluid aspiration (culture and Gram's stain positive, leukocyte count markedly elevated and glucose level low), blood culture positive and positive cultures from other possible sites of infection. Results: Of the 40 patients, 22 were boys, 18 were girls and the male to female ratio was 1.2/1. Patient ages ranged from 6 months to 14 years (mean (+/- SD) 8.44+/-4.18 years). The most observed symptoms were fever (52.5%), arthralgia (50%) and joint swelling (45%). Thirty-four (85%) patients had only one joint and six patients (15%) had more than one joint involved. In total, arthritis was diagnosed in 49 joints. The joints diagnosed as having arthritis were the following: knee (n=18), hip (n=12), ankle (n=12), elbow (n=3), shoulder (n=2), wrist (n=1) and interphalangeal joint (n=1). Of the 40 patients, 21 (52.5%) had SA alone and 19 (47.5%) had arthritis together with osteomyelitis. While arthritis was diagnosed in 27 joints in the group of patients with SA, it was diagnosed in 22 joints in the group of patients with SA combined with osteomyelitis; in the latter, an increase was not observed in the number of joints involved. Joint fluid culture was positive in 22 (55%) patients; the growth of Staphylococcus aureus was observed in 20 cases and Pseudomonas aeruginosa and Staphylococcus epidermidis were isolated in each patient. In contrast, in one patient, arthritis occured during meningococcal meningitis (in this patient, Gram-negative diplococci was isolated from a cerebrospinal fluid culture). Patients with SA combined with osteomyelitis and those with SA alone were compared for symptoms on admission, the history of trauma and antibiotic use, sex, age, fever, joint involvement, anemia, leukocytosis and micro-organisms isolated from joint fluid and blood; there were no significant differences for these parameters between the two groups (P >0.05). In addition, we found that there was no relationship between age and joint involvement in SA and there was no effect of micro-organisms on mortality. Three of 40 patients died; the mortality rate was 7.3%. Of the three patients who died, two had SA alone and one had SA combined with osteomyelitis. The primary disease was sepsis in these three patients; S. aureus was cultured from blood in two patients and Gram-positive cocci was observed following examination of the joint fluid in the other patient. Conclusions: We would like to emphasize that SA is mono-articular, frequently localized in the knee, hip and ankle in 85% of patients, joint fluid culture was positive in 55% of patients, bacteria was isolated from one or more cultures of blood, joint fluid, pus or bone in 70% of patients and the most common isolated micro-organism was S. aureus. In addition, it must be pointed out that children younger than 2 years of age with fever, a positive trauma history and/or abnormal joint findings should be carefully examined for SA because the rate of SA was lower (7.5%) than expected in this age group. We also found that the mortality of SA was not influenced by age, joint involvement and bacterial agents, and there was no significant difference in symptoms on admission, the history of trauma and antibiotic use, sex, age, fever, joint involvement, anemia, leukocytosis and micro-organisms isolated from joint fluid and blood between patients with SA combined with osteomyelitis and SA alone (P >0.05).