What causes headaches?

Headaches are complex in nature and there are multiple types of “headache”. The International headache society distinguishes there to be two categories of headache. Primary (no specific pathology contributing) and Secondary headaches (a specific pathology causing the headache).

In relation to primary headaches (such as: tension headaches and migraine) currently there are multiple theroeis as to what causes the headache. Although previous theories attempted to explain these with vascular dilation in relation to migrains and muscle contraction with tension headaches, further thoughts suggest this may not adequately explain what causes the headaches. Currently, thoughts on a headache such as migraine define a neurological event that causes a cascade of changes in neurotransmitters and chemical mediators  which results in neurogenic vascular inflammation 

 I encourage you to go to http://www.handsonsuperhealth.com.au/index.php/hands-on-blog/ for further information on the causes of headaches and their subtypes. 

Each type of headache will often have different triggers and different causes. You may find on this forum several other posts on what types of headaches there are. 

Simply put; here are some causes of headache:
Vascular/neurologic - decreased blood to the brain (atherosclerosis) /increased pressure on vasculature (vasodilation or hypertension)
Myogenic/cervicogenic - direct pull on periosteum, muscle spasm, referred pain, or nerve entrapment
Metabolic/toxic - decreased glucose to the brain (diabetes, hypoglycaemia), increased metabolism (hyperthyroidism), drug toxicity
Miscellaneous - sinus, eyestrain, cerebrospinal fluid pressure changes etc. 

As Dr Hislop described, there is a classification system of headaches which is produced by the international headache society. Under this system a vast array of headaches have been described (over 300) based on the differences in their outward signs and symptoms.

This system does not adequately answer the question though. What causes them? It just tells us what they look like.

What we know about the underlying pathology of headaches has evolved rapidly over the past decade. 
We know that all major headache types demonstrate abnormal reflexes. Abnormal reflexes are signs of increased or decreased central nervous system activity. In migraine, menstrual migraine, tension type headache, cluster headache and cervicogenic headache we see increased or heightened reflex activity in the brainstem. 
We also see that a family of drugs - the Triptans - whose key action is to decrease the activity in this very specific part of the brainstem, have been shown to be effective across all major headache types.

Does this describe the cause? No. It describes the pathology - an overactive brainstem.

The part of the brainstem that is overactive receives input (other than special senses) from all of the sensory nerves in the face, head, ears, nasal passage, teeth, sinuses, muscles of the scalp and face and inside of the mouth. All the areas that headaches and migraines are felt. This is the outward sign of this overactivity.

PET scans have confirmed in migraineurs that there is overactivity not just during, but outside of an attack.

This overactive area in the brainstem receives significant input from one other key area. The upper three cervical nerves.

If you have dysfunction in the upper cervical spine it has direct access to the “headache centre” in the brainstem.

The neck is significantly underestimated as a source of pain in primary headache. This anatomy of the braintstem allows significant intermingling of the cervical nerves with the nerves that control the output of headache in all its forms.

To read more about the pathophysiology of headache and migraine you can read my blog -http://www.melbourneheadachecentre.com.au/blog.html
or facebook page
http://www.facebook.com/MelbHeadacheCentre

There are a number of different types of headaches.

The neck as mentioned by my colleagues above is a frequent source in a high percentage of people, particualry in those that sit all day and use a computer often.

The most common precipitating factors to mechanical neck headaches are prolonged and repeated loading from poor neck postures. The most common of these is looking down regularly as in reading or using your iphone or ipad, and slouched sitting where the head protrudes forward placing great mechanical strain on the neck.

Every patient needs a thorough individual assessment, but the answer is usually correction of the aggravating postures and specific exercises to relieve the pain and restore movement rapidly.

A qualified McKenzie trained physiotherapist can certainly help you determine quickly if your headaches are mechanical in nature, and if so can you find rapid relief without spending money on scans and endless visits for treatment.