药物过度使用头痛（二）

 英语晨读 ·

山东省立医院疼痛科英语晨读已经坚持10余年的时间了，每天交班前15分钟都会精选一篇英文文献进行阅读和翻译。一是可以保持工作后的英语阅读习惯，二是可以学习前沿的疼痛相关知识。我们会将晨读内容与大家分享，助力疼痛学习。

本次文献选自Wakerley BR. Medication-overuse headache. Pract Neurol. 2019,19(5):399-403.本次学习由谢珺田副主任医师主讲。

Who gets medication-overuse headache?

By definition, medication-overuse headache occurs in people with primary headache who overuse acute medication. Most have a background of migraine or less commonly of tension-type headache. Rarely, it develops in people with cluster headache, although typically there is also a background of migraine or a family history of migraine. Although any analgesic can cause medication-overuse headache, triptans and opioids appear to carry the most risk, and do so in a shorter period.Opioid dependence is common among migraineurs and can be difficult to treat. Medication-overuse headache is three to four times more common in women than men and its peak incidence is in the fourth decade. Those with psychiatric comorbidities, including anxiety and depression, appear most susceptible. Other risk factors include: age below 50 years; low education level; chronic musculoskeletal or gastrointestinal complaints; smoking; physical inactivity; high caffeine intake; and tranquilliser use.

哪些患者易于发生药物过度使用头痛？

根据定义，药物过度使用头痛发生于过度使用急性症状治疗药物的原发性头痛患者。大多数患者都有偏头痛的背景，或者有不太常见的紧张型头痛背景。虽然通常也有偏头痛的背景或偏头痛家族史，但很少发生于丛集性头痛患者。尽管任何止痛药都可能导致药物过度使用引起头痛，但曲坦类和阿片类药物似乎风险最高，而且会在较短的时间内发生。阿片类药物依赖在偏头痛患者中很常见，很难治疗。药物过度使用导致的头痛在女性中的发生率是男性的3~4倍，其发病率在40岁左右达到高峰。那些患有包括焦虑和抑郁在内的精神合并症的患者似乎最易罹患此病。其他风险因素包括：年龄50岁以下；接受教育水平低；慢性肌肉骨骼或胃肠疾病；吸烟；体育锻炼较少；咖啡因摄入量高；使用镇静剂。

Pathophysiology

The pathophysiology of medication-overuse headache remains poorly understood, but probably reflects the complex interplay between brain networks involved in chronification of pain and exposure to certain psychosocial and socioeconomic stressors in genetically predisposed people. Medication-overuse headache seems to result from increased  neuronal hyperexcitability in the cerebral cortex and in the trigeminal nervous system. Hyperexcitability of cortical neurones is associated with the development of the cortical spreading depression that accompanies migraine aura. Hyperexcitability of the trigeminal nervous system facilitates peripheral and central sensitisation, and so is important in chronic pain development.

病理生理学

药物过度使用头痛的病理生理学目前仍知之甚少，但在遗传易感性人群中，可能和参与疼痛慢性化的大脑网状系统，某些心理社会和社会经济应激因素的暴露，以及彼此之间的复杂相互作用有关。药物过度使用导致头痛的原因似乎是大脑皮层和三叉神经系统的神经元过度兴奋性增加。皮质神经元的高兴奋性与伴随偏头痛先兆的皮质泛化抑郁产生有关。三叉神经系统的高兴奋性促进了外周和中枢的敏感性，因此在疼痛慢性化的产生中至关重要。

Medication-overuse headache should perhaps be reclassified as a disorder occurring only in people with chronic migraine. It can develop in people with cluster headache without migraine—although with a family history of migraine—suggesting that certain genes involved in migraine increase the risk of medication-overuse headache, rather than the migraine itself. Polymorphic variants of the dopaminergic gene system and of other genes related to drug-dependence pathways appear the most closely associated with medication-overuse headache. All of these molecules are involved in pain modulation. Prolonged exposure to analgesics can alter neurotransmitter metabolism in pain pathways. Imaging studies in people with medication-overuse headache provide evidence of structural and functional brain alterations.

药物过度使用头痛可能应重新归类为仅发生在慢性偏头痛患者中的一种疾病。虽然有偏头痛家族史表明与偏头痛相关的某些基因会增加药物过度使用头痛的风险，而不是偏头痛本身，但也可以在没有偏头痛的丛集性头痛患者中出现。多巴胺能基因系统和与药物依赖途径相关的其他基因的多态性表达似乎与药物过度使用头痛的关系最为密切。所有这些分子机制均参与疼痛调制过程。长时间接触止痛药可以改变疼痛途径中的神经递质代谢。药物过度使用头痛患者的影像学检查可以提供大脑结构和功能改变的证据。