Lyme arthritis in children: clinical epidemiology and long-term outcomes

Although Lyme disease has become a relatively common cause of arthritis among children in areas of the country in which the disease is endemic, little information is available about the clinical epidemiology and long-term outcomes of children with Lyme arthritis. We conducted a long-term follow-up study to determine the clinical epidemiology of Lyme arthritis in children as well as their long-term outcomes.

All children seen between 1982 and 1991 at the Pediatric Rheumatology Clinic at Newington Children's Hospital (Newington, CT) with an initial diagnosis of Lyme disease were identified. Medical records were reviewed and structured telephone interviews were conducted to obtain demographic, clinical, and follow-up data.

A total of 90 children (63% boys) with a mean age of 8.3 years (range, 1.8-16 years) at the time of diagnosis of Lyme arthritis were evaluated. Lyme arthritis was preceded by early Lyme disease in 23 (26%) of the children; however, only 8 (35%) of these children had been treated with appropriate antimicrobial therapy at that early stage. Ninety percent of the children had arthritis of at least one knee, while small joints were rarely involved. For the 31 children who underwent arthrocentesis, the mean white blood cell count in the synovial fluid was 38 000 cells/mm3 (range, 7000-99 000 cells/mm3) with predominantly neutrophils. For the 79 children for whom an erythrocyte sedimentation rate was determined, the highest level for 61 (77%) was >20 mm/h and for 36 (46%) was >50 mm/h. Antimicrobial therapy was initiated 2 days to 5.5 years (median, 2 months) after the onset of symptoms. However, 5 of the children were never treated with antimicrobials. Fifty-one percent of the patients had a single episode of arthritis, while 49% reported recurrent episodes of arthritis over a period of 1 week to 8 years (median, 6 months). Two children (2%) developed chronic arthritis and underwent arthroscopic synovectomy. At the time of the telephone follow-up evaluation, performed 2 to 12 years (median, 7 years) after the onset of the Lyme arthritis, 4 children had ongoing musculoskeletal complaints that resulted in mild to moderate impairment of school or sports activities, but none of the children had evidence of active arthritis.

The results of this investigation suggest that the prognosis for children with Lyme arthritis who are treated with appropriate antimicrobial therapy is excellent.