Chapter 120. Osteomyelitis (Part 6) potx

Chapter 120. Osteomyelitis (Part 6) Specific therapy is ultimately based on in vitro susceptibility testing of the organism(s) isolated from bone or blood. Outpatient parenteral antimicrobial therapy (OPAT) is appropriate for motivated and medically stable patients and represents a significant advance in management. Antibiotics that require infrequent dosing, such as ceftriaxone, ertapenem, daptomycin, and vancomycin, may facilitate home therapy, but these choices often have an overly broad spectrum of activity. Fortunately, many antibiotics can be given automatically by means of a portable infusion pump, which decreases the disruption otherwise caused by frequent administration of a drug. Use of a peripherally inserted central catheter (PICC line) also greatly facilitates outpatient drug administration. OPAT requires close coordination of nursing, pharmacy, and physician care, with clear delineations of responsibility for monitoring of safety and efficacy. After administration of parenteral therapy for 5–10 days and after resolution of signs of active infection, oral antibiotics have been used with great success in children with hematogenous osteomyelitis. The doses of oral penicillins or cephalosporins required for the treatment of pediatric osteomyelitis are high, and adults may not tolerate such doses as well as children. With the exception of the fluoroquinolones, rifampin, and linezolid, few data support the use of oral antibiotics for adults with osteomyelitis. For treatment of infection due to Enterobacteriaceae, oral administration of a fluoroquinolone has been as successful as IV administration of β-lactam antibiotics. Caution should be exercised in the use of fluoroquinolones as the sole agents for treatment of infection due to S. aureus or P. aeruginosa because resistance may develop during therapy. Addition of oral rifampin (300 mg bid) to a fluoroquinolone has yielded encouraging results in infections due to S. aureus, but potential drug toxicity and drug interactions make this option desirable only for selected patients, such as those for whom parenteral therapy poses unacceptable logistical or financial hardship. Oral administration of metronidazole (500 mg every 8 h) results in high drug levels in serum and can take the place of IV regimens for the treatment of Bacteroides infections. The bacteriostatic drug linezolid (600 mg by mouth every 12 h) has been used successfully in uncontrolled studies involving moderate numbers of patients with infection caused by methicillin-resistant S. aureus (MRSA) and vancomycin-resistant enterococci, but data are currently insufficient to recommend the routine use of this agent. Data do not support the routine use of the serum minimal bactericidal concentration in guiding therapy. Osteomyelitis caused by MRSA is a growing problem that poses unique challenges in terms of treatment. Vancomycin has historically been the drug of choice for MRSA osteomyelitis, but only because of a lack of acceptable alternatives. The drug is less effective than β-lactam agents in treating infections cause by methicillin-susceptible S. aureus (MSSA), and this low efficacy extends to infections caused by MRSA. Vancomycin should not be used for treatment of osteomyelitis caused by MSSA, and oral rifampin should be coadministered with vancomycin when the latter drug is used for MRSA infection unless there are compelling contraindications. Linezolid has performed reasonably well in uncontrolled studies of staphylococcal osteomyelitis. However, side effects and hematologic toxicity are common with this agent; thus, in the absence of controlled studies, its routine use is discouraged. Daptomycin, a bactericidal drug with favorable pharmacokinetics, has also been used successfully. Unfortunately, because resistance can develop during therapy (with resultant treatment failure), the routine use of this drug is not recommended. Trimethoprim-sulfamethoxazole, clindamycin, and tetracycline derivatives (doxycycline and minocycline) are often used—seemingly to good advantage—as "continuation therapy" for MRSA osteomyelitis after a course of a parenteral agent, but no controlled data are available to support this approach. Acute Hematogenous Osteomyelitis Early treatment of acute hematogenous osteomyelitis of childhood with 4–6 weeks of an appropriate antibiotic is usually successful; treatment for <3 weeks has resulted in a tenfold greater rate of failure. Surgical intervention in childhood cases is indicated for intraosseous or subperiosteal abscesses, concomitant septic arthritis, and lack of improvement of the acute signs of infection in 24–48 h. Acute hematogenous osteomyelitis of bones other than the spine in adults often requires surgical debridement. Vertebral Osteomyelitis A 6- to 8-week course of treatment with an appropriate antibiotic is usually sufficient to cure vertebral osteomyelitis. Failure of the ESR to drop by two-thirds or more of its pretreatment level or of the CRP level to normalize is an indication for reevaluation and (possibly) longer treatment. Surgery is seldom necessary, even in cases of many months' duration, except in instances of spinal instability, new or progressive neurologic deficits, or large soft-tissue abscesses that cannot be drained percutaneously. All but small and asymptomatic epidural abscesses should be surgically drained. Patients should maintain bed rest until back pain has declined to the point at which ambulation is possible. Body casts are no longer used except for comfort. . Chapter 120. Osteomyelitis (Part 6) Specific therapy is ultimately based on in vitro susceptibility testing of. osteomyelitis after a course of a parenteral agent, but no controlled data are available to support this approach. Acute Hematogenous Osteomyelitis Early treatment of acute hematogenous osteomyelitis. guiding therapy. Osteomyelitis caused by MRSA is a growing problem that poses unique challenges in terms of treatment. Vancomycin has historically been the drug of choice for MRSA osteomyelitis,