Complex regional pain syndrome
2007/05/24
ü 又稱sympathetic dystrophy
ü Pathophysiology: 因為該處的神經末梢(像是血管的支配神經)受損不正常放電,沿著交感神經傳回中樞引發痛的感覺,並進而影響該處交感神經的function因此會有vasomotor instability,長期的交感興奮使該處血流上升也會造成那邊的bone resorption增加而骨質疏鬆骨頭痛.
ü clinical presentation: 下肢居多,病人會描述肢體疼痛無法動, skin也有alodynia的情形, edema, swelling, skin change, 皮膚溫度和排汗功能不佳.
ü 分兩類: type I—90%, idiopathic,找不到特定原因,佔多數; type II—definable nerve lesion, 舊稱causalgia.
ü Inciting events: 誘發的事件: no predisposing 35%, post-MI 5-20%, hemiplegia 12-20%. 做過knee arthroscope手術的病人60%發生,縮短tourniquet使用時間並早期被動運動可減少發生, 另外大腿處的on H/D cath或是cyclosporine, 還有情緒也都可能是引起的因素.
ü Management:
1. Prevention: early mobilization for stroke, VitC supplement following wrist fracture
2. Pharmacology:
Topical capsaicin止痛
Bisphosphonate (pamidronate, alendronate): 抑制bone resorption and 減少疼痛
Glucocorticoids (prednisone 40mg QD): 比NSAIDS有效,不過臨床上還是建議從NSAIDs使用起
Calcitonin: 抑制骨頭resoprtion
Sympathetic blocker (propranolol, reserpine, guanethidine): IV or PO
Alpha-1 adrenoceptor antagonist (prazocin, terazosin, phenoxybenzamine)
3. invasive treatment
痛點注射methylprednisolone 40mg
à痛點注射3-5天仍無改善,可用AEDs (gabapentin, ;amotrigine)
TENS unit (transcutaneous electrical nerve stimulation)
Epidural clonidine: s/e為低血壓或sedation
Regional sympathetic nerve block: 建議做RST (resting skin temperature) & QSART (quantitative sudomotor axon reflex test)前後比較, 是很好的評估指標. Gaglion block/ IV regional block (用ketorolac, methylprednisolone or bretylium)
Dorsal column spinal cord stimulation
Sympathectomy.
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
結論:
1. 重點在止痛.臨床上分3 stages,不同stage有不同的治療, 越後面或是failure就要使用invasive
2. 診斷方面,影像學上可以輔助的有bone scintigraphy (stage I & II, clinical < 6months者) & plain film (stage III, 可見patchy osteopenia)
3. 診斷此疾病前要先r/o: DVT, infection, other causes leading to limb edema: cardiovascular, renal, hepatic, lymphatic, tumor
