Department of Psychology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA.
J Pain Symptom Manage. 2012 Jun;43(6):1082-93. doi: 10.1016/j.jpainsymman.2011.06.020. Epub 2012 May 11.
Sickle cell disease (SCD) is an inherited hematological disease marked by intense pain. Early in life the pain is episodic, but it becomes increasingly chronic in many cases. Little is known about this emergence of a chronic pain state.
The goal of this study was to determine whether adult SCD patients whose pain is still largely episodic show early signs of the disturbed pain processing (hyperalgesia and increased temporal summation) and cognition (hypervigilance and catastrophizing) that are characteristic of a chronic pain state.
SCD patients (n=22) and healthy controls (n=52) received noxious pressure stimulation for up to three minutes and periodically reported pain intensity and unpleasantness on 0-10 scales, allowing the rate of pain increase (temporal summation) to be determined. Pain intensity discrimination also was measured, and attitudes toward pain were assessed.
There were no overall differences in pain ratings or temporal summation between patient and control groups. However, patients' experimental pain ratings tended to increase with age and those reporting a history of very painful episodes showed particularly rapid temporal summation of pain unpleasantness. Patients were significantly impaired at discriminating intensities of noxious stimulation. Patients were more hypervigilant than controls, but catastrophizing was elevated only during pain episodes.
Most SCD patients whose pain remits entirely between episodes are not in a chronic pain state, but some--those who are older and have a history of highly painful episodes--appear to be transitioning into it. These early signs of disturbed processing may aid clinicians seeking to forestall disease progression.
镰状细胞病（SCD）是一种遗传性血液疾病，其特征是剧烈疼痛。在生命早期，疼痛是间歇性的，但在许多情况下，疼痛会变得越来越慢性。对于这种慢性疼痛状态的出现，人们知之甚少。
本研究的目的是确定疼痛仍主要呈间歇性的成年 SCD 患者是否表现出疼痛处理（痛觉过敏和时间总和增加）和认知（过度警觉和灾难化）紊乱的早期迹象，这些都是慢性疼痛状态的特征。
SCD 患者（n=22）和健康对照组（n=52）接受长达三分钟的有害压力刺激，并定期在 0-10 标度上报告疼痛强度和不适，以确定疼痛增加的速率（时间总和）。还测量了疼痛强度辨别力，并评估了对疼痛的态度。
患者组和对照组在疼痛评分或时间总和方面没有总体差异。然而，患者的实验性疼痛评分随着年龄的增长而增加，那些报告有非常疼痛发作史的患者表现出特别快速的疼痛不愉快时间总和。患者在辨别有害刺激的强度方面明显受损。与对照组相比，患者过度警觉，但只有在疼痛发作时才会出现灾难化。
大多数在发作之间完全缓解疼痛的 SCD 患者并未处于慢性疼痛状态，但有些患者——那些年龄较大且有过非常疼痛发作史的患者——似乎正在进入这种状态。这些处理紊乱的早期迹象可能有助于临床医生预防疾病进展。
