July 21, 2007
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In this month's issue:
Headache classification part 5 - Secondary Headaches
More on head trauma
Say what?! Allodynia
Headache classification part 5 - Secondary Headaches
We're continuing our series on headache classification. So far we've dealt with primary headaches, but now we're going to take a look at secondary headaches.Primary vs Secondary
So what's the difference? Well, it's not really as clear as you might think. You may be diagnosed with a secondary headache when you actually have a migraine. Why?Headaches are considered secondary when there is an obvious, clear cause. For example, if there is a brain tumour, and you develop a headache at the same time, it's called secondary, even if it has all the common symptoms of a migraine.
So although this is a somewhat helpful way to classify headaches, the distinction isn't as real as it may sound. It just means that the doctor will focus on the main cause first (ie a tumour), then she'll see if the headache disappears after that.
There are 8 main classes of secondary headache - we'll do 2 today.
Headache attributed to head and/or neck trauma
Obviously this is headache that comes from a hit in the head or neck. Often the headache goes along with dizziness, lack of concentration, nervousness, personality changes and trouble sleeping. All these symptoms are a part of post-traumatic syndrome. Most of the headaches are similar to tension-type headaches. Interestingly, there's some evidence that milder trauma is more likely to cause headache.This one is a bit different from the rest because it's sometimes hard to establish a cause and effect relationship. For one thing, although headache sometimes starts right after the head injury, sometimes it will take days, weeks, or months to show up. And unlike most of the other types of secondary headache, the headache may or may not go away when the injury is "healed".
Headache attributed to cranial or cervical vascular disorder
This includes a series of things such as ischaemic stroke or attack, various kinds of bleeding around the head/brain, aneurysm, giant cell arteritis, cerebral venous thrombosis, and a host of other disorders related to the blood vessels of the head and neck, including those caused by procedures such as an angiogram.Usually there's a clear relationship between the disorder and the headache. Even if patients already had headache before the disorder, the headache may become worse or change in some way when the disorder begins. Then the headache usually (not always) goes away once the primary issue is dealt with.
Sometimes headache is the main symptom, other times there are serious neurological symptoms (for example, difficulty concentrating, or seizures) that are more of a concern. Often the headache (new headache or worse headache) is the warming sign - if the disorder can be caught early, it's a great advantage!
Headaches related to this category come in all flavours, incuding migraine headache with aura and thunderclap headache.
For more on the headache classifications, you can read The International Classification of Headache Disorders here, thanks to the Migraine Aura Foundation.
More on head trauma
Head trauma is an extremely common cause of headache. However, as we talked about above, it's not always as easy to spot as you might think.One of the most common causes of head trauma is sports. Athletes, from children to professionals, are pressured (either by themselves, their team, coaches, or fans) to stay in the game if they can still contribute, no matter how much pain they may be in. What may seem noble at the time can cause problems down the road - more migraine attacks, headache, and even depression and cognitive problems.
So if your child, friend, team mate or whoever has had head trauma, or is complaining of headaches, keep an eye on them and encourage them to get proper treatment. Read more about head sports trauma here.
The University of Michigan in the USA has a program focused on sport related neurological disease.
This issue has been brought to light again in the Canadian Football League with the injuries of superstar Dave Dickenson (a quarterback from Montana, USA).
Finally, to the unbelievable - a man wakes up with a headache, is taken to the hospital, and discovers the cause - a bullet! His wife apparently shot him. At close range. She claims it was a mistake. Oops. Read the story - Man With Headache Finds Bullet in Head.
Say what?! Allodynia
Allodynia is a general term that means "other pain". It occurs when you get pain from something that normally shouldn't be painful, or when you get pain in one area when a totally different area is stimulated. It's not the same as referred pain.There are different types of allodynia, often associated with disorders of the nervous system. Some types of allodynia are actually pretty common in migraine. Often it's pain on the scalp (cutaneous allodynia), making it painful even to brush your hair. It could also be pain of the skin on other parts of the body (such as the arms), and even muscle tenderness. Read more on allodynia.
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