Molecular and imaging tests have increased the identification of pediatric osteomyelitis, but there are still plenty of challenges and conundrums in the management of these cases.
Part of the problem is that not all children fit the diagnosis of acute uncomplicated osteomyelitis, and fall into a "data-free zone," suggests Dr. Russell McCulloh, an infectious disease specialist with Children’s Mercy Hospital in Kansas City, Mo. Acute hematogenous osteomyelitis (AHOM) accounts for 1% of pediatric hospitalizations, although most studies don’t address complicated osteomyelitis, culture-negative cases, neonates, surgical interventions, cases with hardware in place, and colonization outside of the long bone, the most usual site for osteomyelitis.
Dr. Samir S. Shah
"It’s easy, I think, to look at the abstracts and inadvertently extrapolate the data to patients we just don’t have the data on," he said during a pediatric osteomyelitis roundtable at Pediatric Hospital Medicine 2013 in New Orleans.
In the absence of a consensus on how to manage complicated or culture-negative patients, a surprising number of groups are turning to medium-course therapy. Data have shown that if a peripherally inserted central catheter (PICC) line is in place for 2 weeks or less, there are far fewer complications than if it’s in place for 4-6 weeks. This has led some groups to take the approach of giving intravenous antibiotics for 2 weeks and then transitioning to oral antibiotics if the patient is doing well, observed Dr. Samir S. Shah, director of hospital medicine at Cincinnati Children’s Hospital Medical Center.
"Again, there’s no great data on whether that’s a good strategy or not, but some folks feel that it mitigates some of the challenges with doing a more prolonged course of IV therapy, with their nervousness of transitioning to oral therapy in the process," he said.
The data are fairly clear, however, that oral antibiotics are effective in treating acute, uncomplicated osteomyelitis, and that early transition to oral antibiotics demonstrates similar success to that of long-term IV therapy, said copresenter Dr. Joanna Thomson, a fellow in hospital medicine at Cincinnati Children’s.
One of the best analyses on this issue is a systematic review of 12 studies showing similar 6-month cure rates among children, aged 3 months to 16 years, with AHOM given IV antibiotics for less than 7 days or for 1 week or longer (95.2% vs. 98.8%) (BMC Infect. Dis. 2002;2:16).
Six-month treatment failure rates also were similar between prolonged IV antibiotics and early transition to oral therapy in one of the largest studies of pediatric osteomyelitis, a retrospective cohort study of about 2,000 children carefully screened to exclude all but the most straightforward cases (Pediatrics 2009;123:636-42), she said.
An audience member questioned whether orthopedic surgical involvement tips the diagnostic scales from simple to complicated osteomyelitis, to which Dr. Shah replied that complicated cases typically involve additional problems such as thrombosis, pulmonary septic emboli, metastatic dissemination of infection, or prolonged bacteremia. Another attendee also suggested that cancer should be on clinicians’ radar in patients failing to respond, noting that she had two recent cases including a 5-year-old with neuroblastoma and extensive metastases.
The Pediatric Infectious Diseases Society and the Infectious Diseases Society of America (IDSA) have partnered to create new pediatric guidelines for the diagnosis and management of AHOM. At present, they are considering a possible recommendation that, if approved, would call for early transition to oral antibiotics, said Dr. Shah, a member of the guideline committee.
Clindamycin is a good choice for empiric coverage of Staphylococcus aureus for acute osteomyelitis in stable patients, if the local susceptibility patterns allow, said copresenter Dr. Amanda C. Schondelmeyer, also a hospital medicine fellow at Cincinnati Children’s. Vancomycin should be considered for empiric coverage of S. aureus in patients with bacteremia or abnormal vital signs, while beta-lactam antibiotics can be added for coverage of Kingella kingae in patients under age 3 with septic arthritis.
Dr. Joanna Thomson
Current IDSA guidelines recommend IV vancomycin for children with acute hematogenous methicillin-resistant S. aureus (MRSA) osteomyelitis or septic arthritis. If the patient is stable without ongoing bacteremia or intravascular infection, clindamycin can be used as empiric therapy, if the clindamycin resistance rate is low, for example, less than 10%.
A quick show of hands revealed that while most attendees knew the clindamycin susceptibility pattern for MRSA at their institution, only a handful knew if it exceeded 10%.
An informal survey of the overflow crowd also indicated no clear consensus on what factors are most important in transitioning patients to oral antibiotics. A normalized C-reactive protein (CRP), afebrile state, and at least 48 hours of IV antibiotics were suggested, but some attendees commented that it was rare for CRP values to normalize within 2-3 days of initiating therapy and expressed uncertainty about the optimal CRP threshold to use.