感染症 / 整形外科 / 救急
化膿性関節炎 — 管理パス
急性の熱感腫脹疼痛関節。関節穿刺が鍵。培養後に経験的抗菌。
根拠：AAFP。各ノードはガイドラインの判断ロジックを要約したものであり、原文の転載ではありません。 医療従事者向けの参考情報であり、臨床判断の代替ではありません。日本の関連学会指針および施設プロトコルを優先してください。
ステップごとに回答すると、結論と対応の目安が表示されます。前の質問に戻ることもできます。
ステップ 1 · High suspicion?
Acute hot swollen painful joint — does arthrocentesis support it?
💡 Acute mono/oligo-arthritis with redness, heat, swelling, restricted motion ± fever (systemic symptoms are insensitive). Staph aureus is most common (>80% of non-gonococcal); risk factors = prosthetic joint, pre-existing joint disease (RA), immunosuppression, IVDU, diabetes, recent procedure. Serology/imaging cannot exclude it — arthrocentesis is required.
パス全体像
- 【判断】High suspicion?Acute hot swollen painful joint — does arthrocentesis support it?（Acute mono/oligo-arthritis with redness, heat, swelling, restricted motion ± fever (systemic symptoms are insensitive). Staph aureus is most common (>80% of non-gonococcal); risk factors = prosthetic joint, pre-existing joint disease (RA), immunosuppression, IVDU, diabetes, recent procedure. Serology/imaging cannot exclude it — arthrocentesis is required.）
- Synovial fluid supports / high clinical suspicion → High suspicion → antibiotics + drainage
- Low probability, other arthritis → Low probability
- 【終点】Low probability関節液を細胞数＋分画、グラム染色、培養、結晶検査へ。経験的抗菌は培養後可及的速やかに。
- 【終点】High suspicion → antibiotics + drainageSynovial fluid supportive (WBC often >50,000/mm³, PMN-predominant; not a hard cutoff, Gram stain insensitive, crystals do not exclude)またはhigh clinical suspicion: 1) empiric IV 抗菌薬後にaspiration — cover Gram-positives including MRSA (vancomycin); add Gram-negative cover (a third-generation cephalosporin)で高リスク/elderly/immunosuppressed, add anti-pseudomonal coverに対しIVDU; de-escalate per Gram stain/culture. 2) Joint ドレナージ・減圧 (repeated aspiration/arthroscopy/open washout, orthopedics consult; 手術に対しhip/prosthetic joint/hemodynamic instability). Course ~4 weeks (longerに対しprosthetic joints).
よくある質問
- 化膿性関節炎 — 管理パスはどの臨床課題を扱う診療パスですか？
- 急性の熱感腫脹疼痛関節。関節穿刺が鍵。培養後に経験的抗菌。
- 化膿性関節炎 — 管理パスの主要な意思決定ステップは何ですか？
- High suspicion?
- 化膿性関節炎 — 管理パスはどのような対応方針を示しますか？
- Low probability：関節液を細胞数＋分画、グラム染色、培養、結晶検査へ。経験的抗菌は培養後可及的速やかに。；High suspicion → antibiotics + drainage：Synovial fluid supportive (WBC often >50,000/mm³, PMN-predominant; not a hard cutoff, Gram stain insensitive, crystals do not exclude)またはhigh clinical suspicion: 1) empiric IV 抗菌薬後にaspiration — cover Gram-positives including MRSA (vancomycin); add Gram-negative cover (a third-generation cephalosporin)で高リスク/elderly/immunosuppressed, add anti-pseudomonal coverに対しIVDU; de-escalate per Gram stain/culture. 2) Joint ドレナージ・減圧 (repeated aspiration/arthroscopy/open washout, orthopedics consult; 手術に対しhip/prosthetic joint/hemodynamic instability). Course ~4 weeks (longerに対しprosthetic joints).
- 化膿性関節炎 — 管理パスのうち直ちに対応が必要な状況はどれですか？
- High suspicion → antibiotics + drainage：Synovial fluid supportive (WBC often >50,000/mm³, PMN-predominant; not a hard cutoff, Gram stain insensitive, crystals do not exclude)またはhigh clinical suspicion: 1) empiric IV 抗菌薬後にaspiration — cover Gram-positives including MRSA (vancomycin); add Gram-negative cover (a third-generation cephalosporin)で高リスク/elderly/immunosuppressed, add anti-pseudomonal coverに対しIVDU; de-escalate per Gram stain/culture. 2) Joint ドレナージ・減圧 (repeated aspiration/arthroscopy/open washout, orthopedics consult; 手術に対しhip/prosthetic joint/hemodynamic instability). Course ~4 weeks …
- 化膿性関節炎 — 管理パスはどのガイドラインに基づいていますか？
- AAFP diagnosis and treatment of septic arthritis · 準拠：AAFP
出典
- AAFP diagnosis and treatment of septic arthritis