關節液抽吸(Arthrocentesis)

Indication

1. 區分關節炎的種類(infective? crystalline?)
2. 給予特定治療(關節腔注射)，ex. 葡萄糖水、玻尿酸、PRP

Contraindication

Absolute:

• Puncture site cellulitis or other infection

Relative:

• Coagulopathy(little harm)
• Bacteremia?

Procedure

1. 先用echo掃描關節腔周圍四個象限+觸診，尋找關節液最多的地方，用棉棒末端定位(定位點再用兩個超音波平面確認入針處液體足夠)
2. 無菌消毒*3，至少整個關節完成消毒
3. 戴無菌手套、鋪設無菌洞巾
4. 準備好抽吸針(18-22gauge)，針筒，確認定位後跟病人說明並且垂直入針
5. 保持負壓進針直到抽到關節液，大約抽到20-40cc即可
6. 用紗布將入針處蓋起來並加壓5-10分鐘
7. 告知觀察是否有後續局部紅腫熱痛
   (可局部麻醉不過病人須多挨一針)

Complication

1. 感染(Infection)
2. 出血(Bleeding)
3. 過敏(Allergy)，主要是對關節內注射藥物過敏

Synovial fluid analysis

1. 外觀(General appearance):
   1)質地:透明、混濁
   2)顏色:清澈、黃、紅

usmlepathslides: “ Synovial fluid tubes: From left to right, • normal • noninflammatory (e.g., osteoarthritis) • inflammatory (e.g., rheumatoid arthritis) • septic (e.g., gonococcal septic arthritis) • hemorrhage (e.g., trauma, hemophilia A) ”

2. 關節液常規檢查(Joint fluid routine)
   1) WBC
   #Normal:<200
   #Non inflammatory: 200-2000
   #Inflammatory:2000-50000
   #Septic:>50000
   2) Neutrophil count
   3) Gram stain
   4) Crystal
   #Gout: needle shape and negative birefringent
   #Pseudogout(calcium pyrophosphate deposit): rhomboid and positive birefringent

Joint fluid analysis summary