さまよう薬剤師のブログ

学位を持っても、センスのない、感染制御専門薬剤師のブログ.  I have Ph.D. but less sense ID pharmacist.

小児 細菌性関節炎

整形外科医から相談

 
セファゾリン投与していたが、反応イマイチ…
血液培養は陰性。
 
どのように対応しますか?
 
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Bacterial arthritis requires prompt recognition and management; up to one-third of cases may be accompanied by osteomyelitis. Delays in treatment are associated with long-term sequelae. This is especially true when the hip is involved. 
 
The goals of treatment include sterilization and decompression of the joint space and removal of inflammatory debris to relieve pain and prevent deformity or functional sequelae. Drainage of joint fluid and antimicrobial therapy are the cornerstones of therapy. 
 
Because delayed therapy is associated with long-term sequelae, treatment of infants and children with suspected bacterial arthritis should begin immediately after blood and synovial fluid cultures are obtained. 
 
Drainage of joint fluid
 
We recommend drainage of the joint space in all patients with bacterial arthritis (Grade 1B). Drainage and lavage are necessary to decompress the joint space and to remove inflammatory debris. Drainage can be accomplished through open surgery (arthrotomy), arthroscopy, or needle aspiration. Decisions regarding the optimal drainage procedure for an individual patient should be made on a case-by-case basis, depending upon the site and extent of involvement, duration of symptoms, and the suspected organism. 
 
We recommend surgical drainage (arthrotomy or arthroscopy) for bacterial arthritis of the hip in infants and children (Grade 1C). We suggest arthrotomy as the procedure of choice (Grade 2C)
 
Additional indications for arthrotomy in children with bacterial arthritis may include suspected radiolucent foreign body in children with penetrating injury; large amount of fibrin debris or loculations; debridement in patients with concomitant osteomyelitis; and lack of clinical improvement or persistent positive cultures despite appropriate antimicrobial therapy and multiple needle aspirations. 
 
For joints other than the hip, needle aspiration is an alternative to surgical drainage. 
 
Antibiotics
 
Antibiotic therapy is necessary to sterilize the joint fluid. Antibiotics should be administered as soon as possible after blood and synovial fluid cultures have been obtained. 
 
Initial antimicrobial therapy for bacterial arthritis is administered parenterally. The empiric regimen should target the most common pathogens in a particular patient. 
 
We recommend that empiric therapy include coverage for Staphylococcus aureus in all infants and children (Grade 1A). Depending upon the child's age, Gram stain, and particular clinical circumstances, empiric coverage for additional pathogens may be necessary. As an example, the combination of vancomycin and cefazolin may be advisable for a child between 3 months and 3 years of age with indolent disease in a geographic area with a high prevalence of methicillin-resistant S. aureus. Doses for commonly used drugs are listed in the Table. Empiric therapy can be altered when the susceptibility pattern of the causative bacterium is known. 
 
Specific therapy is based upon culture and susceptibility results. Suggested agents for the most commonly isolated pathogens are provided in the Table . 
 
Bacterial arthritis is usually treated for a total of three weeks for S. aureus arthritis, and two weeks for Streptococcus pneumoniae or Neisseria meningitidis arthritis. Antimicrobial therapy may be discontinued if the erythrocyte sedimentation rate (ESR) and/or C-reactive protein (CRP) have returned to normal by these time points and there is no radiographic evidence of unsuspected osteomyelitis.
 
In neonates (<1 month), we suggest that the entire course of antimicrobial therapy be administered parenterally (Grade 2C). In infants and children older than one month, parenteral therapy is continued at least until clinical and laboratory improvement have been demonstrated, after which the balance of antibiotic therapy can be administered orally. In infants and children older than one month, oral therapy may be initiated if the following criteria are met:
•Clear demonstration of clinical and laboratory improvement
•Decreasing or absent fever
•An oral agent with appropriate coverage is available in a formulation that the child can swallow
•Adherence to the antibiotic and monitoring regimen is assured
 
Doses for commonly used oral drugs are listed in the Table. 
 
Treatment response
 
The adequacy of antibiotic therapy can be assessed by serial clinical examination (fever, pain, range of motion), peripheral white blood cell (WBC) count, ESR and/or CRP, and synovial fluid WBC count and culture. 
 
Patients who do not respond to treatment as expected require reevaluation, adjustment of antimicrobial therapy, and definitive surgical drainage. 
 
Follow-up and outcome
 
Children being treated as outpatients for bacterial arthritis should be seen for follow-up approximately one week after discharge from the hospital, and at one- to two-week intervals thereafter. 
 
●The follow-up visit should include monitoring for continued clinical improvement and for complications related to high-dose antibiotic therapy. We suggest that a complete blood count, ESR, CRP, and biochemical profile, including serum aminotransferases, be obtained at each visit.
 
●Radiographs should be obtained two to three weeks into the course of treatment to look for bone changes indicative of occult osteomyelitis or osteomyelitis of the epiphysis or metaphysis. 
 
●The estimated rate of residual joint dysfunction is 10 to 25 percent; even with appropriate treatment, approximately 40 percent of patients with hip involvement and 10 percent of patients with knee involvement develop significant complications. Factors related to poor outcome include: duration of symptoms before treatment; involvement of the hip: involvement of the hip or shoulder with concomitant osteomyelitis; and age younger than one year. 
 
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