Whale in Medicine

  疼痛

剛過完年，開工的第一個禮拜，疼痛科門診就來了一個49歲正值壯年的病人，5年前因為工作爬高不慎從2層樓高摔落，造成腰椎和多處骨折受傷；那一年因為這個職業傷害，他就動了3次手術，包括一次較大的腰椎內固定重建手術，術後只有短暫的疼痛，接著疼痛停止，卻在3年後在相同的地方又開始痛了起來，而且痛得連在床上翻身都有困難。他的老媽媽陪他一起來，問到這麼多年沒有工作，醫藥費要從何而來，老媽媽只說了 “不然要怎麼辦? 還是要想辦法找出這些錢來啊….”，說的時候眼神轉向一邊悵然地看著地板，主治醫師問她是否有保險，她默默點了一下頭不說話，我們只好把話題轉向她兒子今天的治療。

歷史近五年上出現的個案:

2011年 跳樓自殺的孝子 http://www.fuyu.com.tw/ContentList.asp?MainCatNo=105&SubCatNo=10501&SubAdvCatId=1050101&ContentId=564

2013年 疑因神经痛折磨难忍 纽约一华裔妇女跳楼自杀 http://www.chinanews.com/hr/2013/08-28/5217593.shtml

2014年 脊椎痛症少女，停車場跳樓危 http://www.metrohk.com.hk/?cmd=detail&id=245975

2016年 脊椎病變痛不欲生 6旬男疑受不了輕生 https://btrend.amassly.com/post/b9a67lfsfg/

5分鐘內就可以搜尋到這麼多個案，顯示其實到今天號稱醫藥已經非常進步，仍然在疼痛治療上還有許多不足的地方，而且是嚴重不足到讓生病的人會想輕生的程度，顯然這些病人應該也都已經知道現今的醫療能夠幫忙他們的都已經做了，但是遠遠不是他們想要的。

疼痛控制的障礙:

在醫護人員方面:

疼痛處置的知識不足

疼痛評估不適當

藥品管制法iv的過分顧慮

害怕導致患者成癮

過分顧慮止痛藥物的副作用

顧慮患者會藥物產生抗藥性 tolerant to analgesics.

在病患方面:

猶豫告知疼痛

顧慮會因而使醫師不能專心於其癌病

恐懼疼痛可能是癌病惡化的徴象

怕未能表現為一”好”病患

猶豫而未服用止痛藥物

害怕成癮或被認為是一成癮者

擔心藥物的副作用

擔心藥越用越無效

治療疼痛之三大原則: (WHO)

疼痛評估、選擇適當的治療方法、持續照顧 / 3B原則[By the mouth、clock、ladder]

疼痛型態:

體感性疼痛(Somatic pain) : 體表、肌肉、骨骼受傷造成；

位置較明確，性質多是刀刺痛(stabbing)、銳痛(sharp)、搏動性疼痛(throbbing)等；

用一般的止痛藥(NSAIDs、Acetaminophen、COX-2 selective inhibitors)效果就會不錯。

內臟性疼痛(Visceral pain) : 臟器、中空器官、平滑肌受傷造成；

  定位困難，性質多是悶痛(dull)、絞痛(cramping)、甚至有referred pain；

  此類的病人則需要鴉片類止痛藥(opioids)才會比較足夠。

神經病變性疼痛(Neuropathic pain): 神經組織受損造成。

  性質會呈現不悅異常感(dysesthesias): 灼痛(burning)、刺痛(tingling)、電擊痛(shock-like)、

  觸摸痛(allodynia)、痛覺過度(hyperalgesia)、對痛覺刺激遲鈍(hypalgesia)；

  此類的疼痛就會需要合併輔助劑來做治療，像是類固醇、抗憂鬱劑和抗痙攣劑。

偶發痛(Incident pain) : 當身體移動時會出現的疼痛；

  可在移動身體前先服用藥物預防疼痛，所以找出最理想的止痛藥物是當務之急；

也可適當的使用非鴉片類止痛藥和輔助劑；

放射性治療、神經阻斷和手術治療都是可以考慮的止痛方式。

脊椎受傷引起的疼痛:

  脊髓壓迫症候群(spinal cord compression): 常常是以背痛表現(95%)，此為醫療急症，宜於24-48小時內實施治療，立即止痛方式包括 Dexamethasone 10-100 mg IV、緊急放射線(緩和)治療、手術治療等。

生產引起的疼痛:

  一般是硬膜外(Epidural)麻醉止痛會優於脊髓(spinal)麻醉，再優於全身麻醉；

  第一產程的疼痛屬於內臟性疼痛(Visceral pain)，痛覺神經由第十、十一、十二胸椎及第一腰椎傳到中樞，此時的陣痛在第一產程後期以肚臍以下的腹部最為疼痛；

  第二產程的疼痛屬於體感性疼痛(Somatic pain)，痛覺神經經由第二至四薦椎神經傳遞，此產程的痛覺會傳到會陰及肛門處且會伴有便意。

胰臟癌引起的疼痛:

  可以用神經阻斷來止痛；Celiac Plexus Block – relieve of pain from non-pelvic intra-abdominal organs.

  一般用來治療疼痛的方法包括以下幾種:

• 藥物
• 復健、運動
• 冷敷、熱敷、按摩
• 針灸
• 神經電刺激
• 神經阻斷術

用神經阻斷來止痛也有以下運用:

腦神經阻斷術: 例如用在顏面或頭頸部疼痛的三叉神經或其神經節阻斷術。

周邊神經阻斷術: 廣泛用在四肢和頭頸部疼痛。

關節、脊椎疼痛相關神經阻斷術。

交感神經節阻斷術: 如下

若是會陰、骨盆的疼痛: inferior hypogastric plexus block。

Stellate ganglion block(cervicothoracic sympathetic block)則可以用來緩解以下疼痛:

• Thrombo-angitis obliterans (閉塞性血栓血管炎；又叫做Buerger's disease)
• Refractory angina
• Phantom limb pain (幻肢痛；又叫做鬼腳痛)
• Migraine
• Scleroderma

Lumbar sympathetic blocks (performed at ~ L2) have been used for:

• Upper and Lower: CRPS (primary indication), vascular insufficiency (ex. Raynaud’s, diabetes, or frostbite), phantom limb pain, hyperhidrosis, herpes zoster
• Upper only: angina
• Lower only: labor pain, cystitis

2歲以內的小兒疝氣修補術最常用的術後止痛則是採用尾椎阻斷(Caudal block)。

另外，用含藥貼片(ex, Fentanyl patch)來止痛也是一個不錯的選擇，但是因為她到達血中止痛濃度約需要10-12小時，且其呼吸抑制對手術後疼痛較難控制，所以一般是用在癌症疼痛控制。

Strong opioids: Fentanyl-TTS、Morphine、Methadone

Weak opioids: Codeine、Tramadol、Dextropropoxyphene、Tilidin/Naloxon

Non-Opioids: ASA、Ibuprofen、Diclofenac、Cox-2 inhibitors、Paracetamol

Acetaminophen & NSAIDs:

• 一般採用口服即有很好的效果；
• 若出現噁心嘔吐時，可改用栓劑投與；
• IM的方式因為吸收不穩定較不建議；
• NSAIDs對血小板功能會有抑制作用，不適合凝血障礙及出血傾向的病人；
• 若出現胃腸道副作用的風險較高時，可同時給予misoprostol, 200mcg, BID/TID, 作為預防；
• 若是已經有胃腸道副作用，但仍需持續用NSAIDs時，可給予omeprazole 20mg, QD

計算過去24小時口服嗎啡的總劑量,口服嗎啡的劑量為非經腸道吸收嗎啡劑量之3倍(IV), 2倍(SC)。

• 口服嗎啡常用的按時服藥起始劑量是5-10mg, Q4H。在多次給藥之後，短效型嗎啡在12-15小時內就可以達到穩定的血中濃度，所以臨床上在相隔24小時之後，即應依病患的需要來調整劑量。
• 嗎啡的其他給藥途徑包括:IV、SC、PCA(patient-controlled analgesia)、脊椎內輸注。
• 嗎啡PCA的用法:
  • 一般患者: 2-5mg初始劑量(loading dose) + 0.05mg/Kg(basal rate) + 2mg間歇性給藥(10-15min)
  • ≧ 70 y/o 或有肝腎衰竭的患者: 0.4-1mg初始劑量(loading dose) + 0.01mg/Kg(basal rate) + 0.4mg間歇性給藥(10-15min)

• 脊椎內輸注包括椎管內(intrathecal；spinal)或硬膜外(epidural)，可以和局部麻醉劑混合使用，對長期患有頑抗性的下半身疼痛患者有很好的止痛療效。

FDA Approved Drugs for pain:

2016 FDA Approved Drugs: [http://www.centerwatch.com/drug-information/fda-approved-drugs/year/2014]

• Onzetra Xsail (sumatriptan nasal powder) ; Avanir; For the treatment of migraine, Approved January 2016

2015 FDA Approved Drugs:

• Belbuca (buprenorphine) ; Endo Pharmaceuticals; For the management of severe pain, Approved October 2015
• Vivlodex (meloxicam) ; Iroko Pharmaceuticals; For the management of osteoarthritis pain, Approved October 2015

2014 FDA Approved Drugs:

• Tivorbex (indomethacin); Iroko Pharmaceuticals; For the treatment of acute pain, Approved February of 2014
• Xartemis XR (oxycodone hydrochloride and acetaminophen) extended release; Mallinckrodt Pharmaceuticals; For the management of acute pain, Approved March 2014
• Dyloject (diclofenac sodium) Injection; Hospira; For the management of mild, moderate or severe pain, Approved December 2014
• Targiniq ER (oxycodone hydrochloride + naloxone hydrochloride) extended-release tablets; Purdue Pharma; For the management of severe chronic pain, Approved July 2014
• Bunavail (buprenorphine and naloxone); BioDelivery Sciences; For the maintenance treatment of opioid dependence, Approved June 2014

Radicular pain is a type of pain that radiates into the lower extremity directly along the course of a spinal nerve root.

http://www.spine-health.com/glossary/radicular-pain-and-radiculopathy

• Radicular pain can be effectively treated conservatively (non-surgically) with physical therapy, medications and epidural injections.
• If conservative treatments fail, decompressive surgery, such as a laminectomy  or discectomy, may alleviate radicular pain.

Level of Evidence: Therapeutic Level IV.

Finding: The majority of patients (17/21) with lumbar radicular pain who avoid an operation which is arranged by the treating surgeon for at least one year after receiving a nerve root injection with bupivacaine alone or in combination with betamethasone will continue to avoid operative intervention for a minimum of five years.

http://jbjs.org/content/88/8/1722

One of the findings: According to evidence-based practice guidelines(American Society of Interventional Pain Physicians (ASIPP) Guidelines), the evidence for transforaminal epidural steroid injections is strong for short-term and moderate for long-term improvement in managing lumbar nerve root pain, whereas, it is moderate for cervical nerve root pain and limited in managing pain secondary to lumbar post laminectomy syndrome and spinal stenosis.

• There is a lack of consensus regarding the diagnosis and treatment of intervertebral disc disorders.
• Based on controlled evaluations, lumbar intervertebral discs have been shown to be the source of chronic back pain without disc herniation in 26% to 39% of patients. Lumbar provocation discography, which includes disc stimulation and morphological evaluation, is often used to distinguish a painful disc from other potential sources of pain.
• Objective: To systematically assess and re-evaluate the diagnostic accuracy of lumbar discography.
• Conclusion: This systematic review illustrates that lumbar provocation discography performed according to the International Association for the Study of Pain (IASP) criteria may be a useful tool for evaluating chronic lumbar discogenic pain.
• http://www.painphysicianjournal.com/2013/april/2013;16;SE55-SE95.pdf

• Background: Lumbosacral selective nerve root blocks and/ or transforaminal epidural injections are used for diagnosis and treatment of different disorders causing low back and lower extremity pain.
• A clear consensus on the use of selective nerve root injections as a diagnostic tool does not currently exist. Additionally, the validity of this procedure as a diagnostic tool is not clear.
• Objective: To evaluate and update the accuracy of selective nerve root injections in diagnosing lumbar spinal disorders.
• Results: There is limited evidence for the accuracy of selective nerve root injections as a diagnostic tool for lumbosacral disorders. There is limited evidence for their use in the preoperative evaluation of patients with negative or inconclusive imaging studies.
• http://www.painphysicianjournal.com/2013/april/2013;16;SE97-SE124.pdf

• CASE REPORT:
• An 82-year-old retired nurse (who had sustained osteoporotic compression fractures of the T12 vertebra) who presented with a 2-year history of continuous low back pain following a fall into a pothole. Immediately after image-guided, transforaminal infiltration of left side T12 root the patient developed sudden onset of complete motor and sensory T10 level flaccid paraplegia. No abnormality was noted on T2 magnetic resonance imaging (MRI) of the spine on the same day. Eleven days later, T2 MRI of the spine with gadolinium contrast revealed an increased fluid signal in conus medullaris. At 2-year follow-up, the neurological improvement has been good (L2 level American Spinal Injury Association/International Spinal Cord Society (ASIA/ISCoS) neurological standard scale (AIS) D paraplegia), urinary and sensory disorders are still present.
• http://www.ncbi.nlm.nih.gov/pubmed/25900289

• BACKGROUND:

  Image guided intercostal blocks are commonly performed and considered relatively safe. Chemical denervation is commonly used in clinical practice for treatment of chronic non-cancer associated pain.

• RESULTS/CASE REPORTS: A 53 year-old women was transferred from her local facility for acute onset of lower extremity paresis beginning shortly after right intercostal nerve injections of 2 mL of preservative-free phenol at the T7, 8, 9 levels. She had previous intercostal blocks for chronic right-sided mid thoracic/abdominal pain every 3 months for at least one year without sequelae. Within 20 minutes of the injection, she developed a sensation of right leg weakness and heaviness. Over several hours she developed worsening right leg weakness, and then left leg weakness, followed by urinary retention. Admission examination revealed severe right greater than left leg weakness, right lower extremity hyperesthesia to T10, absent lower extremity reflexes, and bilateral extensor plantar responses.
• CONCLUSION:

  Several lessons for a pain specialist including:

  1) the potential for a neurologic catastrophe (spinal cord injury) from aqueous neurolytic intercostal blocks despite "safe" contrast spread;

  2) potential mechanisms of neurogenic injury with intercostal blocks;

  3) review of modifiable factors to decrease the risk of neurogenic injury;

  and 4) review of potential interventions (steroids, lumbar drain) to improve outcome in the setting of iatrogenic procedural related spinal cord injury.

• http://www.ncbi.nlm.nih.gov/pubmed/24658489