Migraines are one of four types of primary headaches, and they come in two forms, those with an aura and those without. The other three primary headaches are tension headaches, cluster headaches and, the catch-all type known as, other primary headaches. These include things like exercise induced or cough induced headaches.
No one knows for sure the exact mechanisms that cause migraines, but we do know it’s a neurobiological disorder, which I’ll get to in a minute..
To begin with, let’s look at headaches in general. Headaches come in two forms, primary and secondary. A primary headache is one where the headache is the problem, and as such, is the cause of your symptoms. A secondary headache is one where the headache is the result of something else, like a stroke or a hangover. (See: What Causes Strokes)
Whether a migraine, or a headache caused by binge drinking, it’s extremely difficult for medical professionals to differentiate between the different types. This is because they all come with very similar symptoms.
For your doctor to diagnose you with having migraines, and as such be treated with medications for them, your headache must meet the following criteria: you must have at least 5 attacks per year that all have the same presentation; the headache last 4-72 hours; be associated with nausea and/or vomiting; and come with photophobia (intolerance to light) or phonophobia (intolerance to sound). The pain associated with your headache must also meet some criteria: it should only be on one side of your head; have a pulsating quality that is moderate or severe; and is aggravated, or causes the avoidance of, physical activity.
To say your migraine comes with an aura (a specific sensation that precedes the migraine), the aura itself has to meet some benchmarks. Specifically, it has to be fully reversible, and at least one aura symptom gradually spreads over 5 minutes or longer, or you have two or more symptoms that occur in succession. Each aura must last 5-60 minutes and be accompanied by a migraine within an hour (although some studies have suggested this time frame be extended to days). Common aura symptoms include nausea, fatigue, difficulty concentrating, stiff neck, and repetitive yawning. The most common aura is a visual one that can involve sensitivity to light or blurred vision.
Migraines without an aura were once thought to blood-flow related, specifically a decrease in blood flow to the brain. Brain images of people with migraines have shown this to be, most likely, false. The only blood-flow changes to any specific brain area have been to the brain stem. It has been suggested that these changes are more likely the result of pain, and not the cause itself.
While no one has definitively shown the exact origin of migraines, as mentioned, it’s now known to be a neurobiological disorder. This basically means, it’s an illness of the nervous system that’s caused by biological factors like genetics or metabolism. This is known because of several ancillary findings.
Studies have shown the messenger molecules nitric oxide, 5-hydroxytryptamine, and calcitonin gene-related peptide are involved with this type of headache. A class of drugs, known as triptans, has also shown to be extremely effective in treating this type of migraine. This drug class specifically targets the receptor sites for these messenger molecules and either inhibits them, or helps them. Researchers have shown that if you help the messenger molecule for 5-hydroxytryptamine, or inhibit the molecule calcitonin gene-related peptide, headache symptoms can be greatly reduced.
While the migraine itself isn’t blood flow related, the aura’s associated are. Studies show blood flow to the region of the cortex associated with the headache is decreased before, or happens simultaneously, with the onset of aura symptoms. This decrease tends to start in the back of the affected area and spreads to the front. It can also reach levels that indicate the cells in that area aren’t getting enough oxygen and nutrients for normal function.
Due to the fact that no one has nailed down the exact cause of migraines- outside of generic external triggers ranging from things like bright lights to certain foods, to specific smells- the treatment for them revolves around two things: prevention, and pain management during an episode. Prevention can include drugs from many different classes, such as ones that treat high blood pressure, like Beta-blockers, to ones that treat seizures, like Depakote. Prevention can also include identifying and then avoiding triggers for a given individual.
Medications used to manage the symptoms during an attack can include the aforementioned Triptans, like Imitrex. Drugs that affect Seratonin levels can also be prescribed. Anti-nausea drugs like Benadryl, and pain medications, like Codeine, are also extremely common.
In the end, basic neuroscience, as well as clinical research, is rapidly advancing our understanding of migraines and their underlying causes. With any luck, and a lot of continued research, migraines will soon become a thing of the past.
原发性头痛是偏头痛的四种类型之一，它们有两种形式，一种有预兆另一种没有。其他三种类型的头痛主要是紧张性头痛、丛集性头痛、全方位头痛，以及其他类型的原发性头痛。包括由运动或咳嗽诱发的头痛。
没有人确切知道偏头痛的发病机制，但我们知道这是神经生物学上的障碍，会让人在一分钟内发病。
首先，让我们来认识下头痛。头痛分为两种，原发性和继发性。原发性的头痛是造成你有此症状。而继发性是由其他一些原因引起的，比如中风和宿醉。
是否是偏头痛或是否是由酗酒引起的头痛，让医学专家来区分这些类型是十分困难的。因为它们的症状十分相似。
医生诊断为偏头痛并为你开药，你的头痛必须符合下列标准：每年至少发病5次；每次持续时间为4-72小时；伴有恶心和呕吐；畏光或害怕高声恐吓。与你头痛相关的病症还必须符合以下的条件：只在头部的一侧；脉动的减轻或加剧；由于身体活动的加剧或减缓。
你的偏头痛有预兆，这预兆也要符合一定的标准。具体的说，预兆症状必须持续5分钟或者更长，或者发生两个或两个以上预兆。每个预兆必须持续5-60分钟，在一个小时里伴有偏头痛(尽管一些研究表明这个时间可能会持续一天)。常见的预兆包括恶心、疲劳、注意力不集中、脖子僵硬、不停的打哈欠。最常见的预兆就是对光线敏感且视力模糊。
没有预兆的偏头痛被认为是与血流有关，流向大脑的血流减少。但偏头痛者的大脑图像显示这可能是假的。大脑中血流唯一改变的区域是脑干。有人认为这可能是造成头痛的结果而不是原因。
没有人确切的知道偏头痛的具体原因，但正如前面提到的，与神经生物学障碍有关。这就意味着这是一种有生物因素引起的神经系统疾病例如遗传或新陈代谢。这是经过几个辅助研究而得出的结论。
研究发现，信使分子一氧化氮、5 -羟色胺、降钙素相关肽与某种偏头痛有关。一种叫做区普坦类的药物治疗偏头痛十分有效。这种要专门针对信使分子的受体，抑制它们或帮助他们。研究人员发现，如果你帮助5 -羟色胺的信使分子或抑制降钙素相关肽可大大减少头痛症状。
偏头痛本身与血流无关，但预兆与血流有关，研究表明血流在大脑皮层流动时伴随着预兆的开始，并且是在头痛减轻前或与头痛同时开始。这种减轻是从受影响区域的后部向前传播，它能到达的水平表现了这个区域的细胞没有足够的氧气行使正常的功能。
因为没有人能从灯光或食物这些因素中确定造成偏头痛的外部因素，所以治疗方法也围绕着两件事：预防和减轻疼痛。预防可以利用许多不同类型的药物，例如治疗高血压的β受体阻滞剂、治疗癫痫的拉莫。
控制症状的药物例如曲普坦类。止吐药物,如苯那君止痛的药物,如可待因。
最后要感谢神经科学以及临床研究，使我们能快速的了解偏头痛。如果我们继续研究下去，运气好的话，偏头痛可能就只会存在在历史之中了
