ALBUQUERQUE Community-acquired methicillin-resistant Staphylococcus aureus is causing a growing number of sudden, severe musculoskeletal infections in otherwise healthy children, according to two reports at the annual meeting of the Pediatric Orthopaedic Society of North America.
Investigators from Indiana University in Indianapolis and from Children's Hospital of Alabama in Birmingham warned in separate posters that sepsis and other comorbidities are common in these cases along with multiple, sometimes asymptomatic, sites of involvement.
In separate interviews, Dr. John P. Lubicky, of Indiana University, and Dr. Shawn R. Gilbert of the University of Alabama at Birmingham suggested that unfamiliarity with musculoskeletal presentation of community-acquired MRSA infections may be causing dangerous delays in diagnosis.
"The kids are sick as hell. Some nearly die," Dr. Lubicky said, urging clinicians to raise their index of suspicion. Unless a physician has seen one of these infections before, he said, community-acquired MRSA is not likely to come to mind when children present with fever and don't move around much.
"Several of the patients had signs of infection in a knee or ankle for a few days, and it took them a while to get appropriate treatment," Dr. Gilbert said, calling for more aggressive treatment when these infections present.
The Indiana Experience
Searching for MRSA-positive musculoskeletal infections treated from January 2003 to February 2008, Dr. Lubicky and his coauthors found 12 community-acquired cases in children who did not have an underlying disease. The average age was 7.2 years (range 0.217.7 years). Nine of the children were boys.
"A lot of the kids are blatantly healthy. There is no obvious source for them to get infected," Dr. Lubicky said, emphasizing that the children in the retrospective study had been active before taking sick. One boy, he recalled, recently had fallen off a skateboard.
Long hospital stays were the norm with an average of 20.5 days (range 442 days). Eleven children required surgical interventions. Complications included pyomyositis in 7 children, septic arthritis in 6 children, and osteomyelitis in 10 children (among them 3 cases that were multifocal and 2 that were fractures). Four children had septic emboli and one had pneumonia.
Dr. Lubicky and his colleagues recommended magnetic resonance imaging of the whole body, if possible, to check for multiple remote sites when community-acquired MRSA is suspected. Treatment often involves medical and surgical interventions, they said, warning that abscesses should be drained early and may need to be drained repeatedly.
The investigators said to start empiric antibiotic treatment against both methicillin-susceptible and methicillin-resistant bacterial strains. A 6-week course of treatment, starting with parenteral administration and followed by oral antibiotics against susceptible isolates, is usually adequate, they said. Eight children in the retrospective study were treated with vancomycin and clindamycin.
The Alabama Experience
Dr. Gilbert and his colleagues found 156 cases of culture-proven S. aureus infections when they searched community-acquired septic arthritis or osteomyelitis cases from 2001 to 2007. Of these, 66 cases (42%) were methicillin resistant, including 8 cases of multifocal musculoskeletal infection. In comparison, only 1 child among 90 with methicillin-sensitive infection was affected at more than one sitebringing the total number of multifocal musculoskeletal S. aureus infections to 9.
The number of multifocal infections doubled from three during 20012004 to six during 20052007. The number of sites also increased from 23 during the early period to 27 (average 3.8) during the later years.
Serious complications became more common over time as well. One child had bacteremia and none had septic emboli in the early multifocal group. Among the multifocal cases after 2004, four children presented with bacteremia and all six children had septic emboli. Dr. Gilbert said that he now routinely samples all high-risk joints, such as the hips, and any joints with obvious swelling.
Several 'had signs of infection in a knee or ankle for a few days, and it took them a while to get appropriate treatment.' DR. GILBERT