Dr. Robert F. Kidd
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Dental & General Health
80% of the population experience headache at some point of their lives. Headaches are so common, that some people will refer to their own as "normal headaches", as if it is normal to have them. The vast majority of them are "tension" or "migraine" headaches. Many people have both.
These common headaches can be disabling some of the time, but are not dangerous in the sense of leading to any serious disease. In fact they tend to become less frequent and severe later in life. Migraines in old age are unusual.
The first responsibility of the physician is to rule out unusual and sometimes serious causes of headache, such as tumour and aneurysm. This is not usually difficult if the patient's story is listened to carefully. The history usually tells the tale, but a careful physical examination is important too.
Tension and migraine headaches share many characteristics. They have so many similarities that neurologists tend to consider them variants of the same condition. This is useful to know as the same principles can then be applied in searching for the causes of either.
Searching for the causes of common headaches is a neglected art. Often more effort is spent in finding a drug that will relieve pain than to find its cause. Drug companies certainly have no incentive to find cures. And time and financial pressures tend to push physicians towards prescribing, rather than exploring the origins of their patients' headaches.
Many patients are aware of "triggers" of their headaches. Fatigue, stress, changes in barometric pressure, certain foods, wine, exposure to molds, perfumes, etc. are common examples. Although it is useful to be aware of these, often they cannot be avoided. Rather the underlying predisposition needs to be understood and if possible, altered to provide lasting relief, or a cure.
A useful tool in understanding headaches is the concept of "summation". This is a neurophysiological term describing the combination of two or more sub-threshold inputs to reach a certain threshold of activity in the nervous system. For example, a trigger point in a neck muscle (from an old injury) might not by itself normally produce a headache. An abnormal electrical current between a dental crown and an adjacent filling might also be harmless in a similar way. However, if both stimuli occur at the same time, there might be enough input to the nervous system to cause a tension headache.
There are many possible generators of headache. These may be local areas of irritation such as trigger points in muscles, unstable neck joints, pressure in cranial sutures, chronic infections in or near teeth, scars (almost anywhere in the body), overactive autonomic ganglia, etc. Finding these locations is like detective work. Attention must be paid to details - from the patient's history and from the physical examination.
Also thresholds of excitation may change. In other words, the whole nervous system, or parts of it, may become more or less excitable. Women experience this near their time of menstruation, when hormonal changes often bring headaches to the surface. And most people find that they have fewer headaches when well rested or on holiday.
There are therefore two choices in treating common headache. One is to detect and treat the focal points that are generating pain. The other is to find and treat the factors that alter the general threshold of pain in the nervous system.