Immunoglobulin Treatment for Complex Regional Pain Syndrome.,Annals of Internal Medicine

What is the problem and what is known about it so far?

Complex regional pain syndrome (CRPS) is an uncommon pain condition. It usually affects a limb after an injury. The main symptom is pain. In some instances, pain is mild and may eventually go away. In other instances, it is severe, persistent, and disabling. Effective treatments for patients with chronic disabling CRPS are needed.

Why did the researchers do this particular study?

To see whether treatment with low-dose immunoglobulin reduces pain more than placebo in adults with CRPS.

Who was studied?

111 adult patients with moderate or severe CRPS of 1 to 5 years' duration.

How was the study done?

Patients recorded daily pain intensity on a scale of 0 to 10 in a pain diary. They also completed questionnaires, at baseline and 6 weeks later, that assessed quality of life and whether pain interfered with activities. Patients were randomly assigned to receive 2 infusions of low-dose immunoglobulin (0.5 g/kg of body weight) or identical placebo given through a vein on days 1 and 22 after randomization. None of the patients, care providers, or researchers knew who received which treatment. Researchers then compared patients' reported pain intensity between days 6 and 42, as well as the other outcomes, between groups.

What did the researchers find?

The average pain intensity score at baseline for each group was about 7.5. All patients reported very low quality of life and that pain had a major effect on their everyday activities. Immunoglobulin infusions did not reduce pain. At follow-up, no clinically important differences were seen between groups in pain intensity, quality of life, or pain interference with activities. One patient who received immunoglobulin reported severe headaches. One patient who received placebo reported severe headaches and vomiting.

What were the limitations of the study?

The moderate-sized study could not examine whether particular subgroups of patients might benefit from treatment and tested only a low-dose treatment regimen.

What are the implications of the study?

Low-dose immunoglobulin treatment over 6 weeks does not relieve pain in patients with persistent, moderate to severe CRPS.

问题是什么？到目前为止我们知道什么？

复杂区域疼痛综合征 (CRPS) 是一种罕见的疼痛状况。它通常会在受伤后影响肢体。主要症状是疼痛。在某些情况下，疼痛是轻微的，最终可能会消失。在其他情况下，它是严重的、持久的和致残的。需要对慢性致残 CRPS 患者进行有效治疗。

研究是如何进行的？

患者在疼痛日记中以 0 到 10 的等级记录每天的疼痛强度。他们还在基线和 6 周后完成了问卷调查，评估生活质量以及疼痛是否干扰活动。患者被随机分配接受 2 次低剂量免疫球蛋白（0.5 g/kg 体重）输注或在随机分组后第 1 天和第 22 天通过静脉给予相同的安慰剂。患者、护理提供者或研究人员都不知道谁接受了哪种治疗。然后，研究人员比较了患者在第 6 天和第 42 天之间报告的疼痛强度，以及组间的其他结果。

研究人员发现了什么？

每组基线时的平均疼痛强度评分约为 7.5。所有患者的生活质量都非常低，疼痛对他们的日常活动产生了重大影响。免疫球蛋白输注并没有减轻疼痛。在随访中，两组之间在疼痛强度、生活质量或疼痛对活动的干扰方面没有发现有临床意义的差异。一名接受免疫球蛋白治疗的患者报告了严重的头痛。一名接受安慰剂的患者报告了严重的头痛和呕吐。