The clinician’s first goal when confronted with a patient with cranial pain is to determine if the headache is primary, in which head pain is the only identifiable disease, or if it is a secondary cranial pain. The main primary headache syndromes are migraine, tension-type headache, cluster headache, and the trigeminal–sympathetic migraine variants of migraine or cluster. These primary headache disorders tend to be chronic, recurrent, and unattended by other symptoms and signs of neurologic disease. Familiarity with the variety of symptoms, temporal profiles, and accompanying features of the primary headache disorders, and the proclivity for many of them to be familial, assist in identifying them from the patient’s description. There should be little difficulty in recognizing the secondary headaches of diseases such as glaucoma, purulent sinusitis, subarachnoid hemorrhage, and bacterial or viral meningitis provided that these sources of headache are kept in mind. A fuller account of these types of “secondary” headache syndromes is given in later chapters of the book, where the underlying diseases are described. All other headaches that by their localization, quality of pain, and precipitating characteristics do not conform to one of the primary types should be suspected of being symptomatic of a cranial, cervical, or systemic disorder. Nonetheless, in many instances no such underlying cause will be found after investigation.
The following broad categories of headaches should be considered (Table 9-1). In general, the classification of these headaches and other types of craniofacial pain follow the plan outlined by the International Headache Society (see http://www.ihs-classification.org/en).
Migraine is a highly prevalent and largely familial disorder characterized by periodic, commonly unilateral, usually pulsatile headaches that often begin in childhood, adolescence, or early adult life and recurs with diminishing frequency during advancing years.
Two closely related clinical syndromes have been identified, the first called migraine with aura and the second, migraine without aura (terminology of the International Headache Society). For many years, the first syndrome was referred to as classic or neurologic migraine and the second as common migraine. Individuals may experience both types over their lives. The ratio of classic to common migraine is 1:5. Either type may be preceded by vague premonitory changes in mood and appetite. Migraine with aura is ushered in by a disturbance of nervous function, most often visual, followed in a few minutes to hours by hemicranial (or, in about one-third of cases, bilateral) headache, nausea, and sometimes vomiting, all of which last for hours or as long as a day or more. Migraine without aura is characterized by an unheralded onset over minutes or longer of increasing hemicranial headache or, less often, by generalized headache with or without nausea and vomiting, which then follows the same temporal pattern as the migraine with aura. Sensitivity to light, noise, and often smells (photophobia, phonoor sonophobia, and osmophobia) attends both types, and intensification with movement of the head is common. If the pain is severe, the patient prefers to lie down in a quiet, darkened room and tries to sleep. The hemicranial and the throbbing (pulsating) aspects of migraine are its most characteristic features in comparison to other headache types. Each patient displays a proclivity for the pain to affect one side or the other of the cranium, but not exclusively, so that some bouts are on the other side or on both sides.
The heritable nature of migraine is apparent from its occurrence in several members of the family of the same and successive generations in 60 to 80 percent of cases; the familial frequency of common migraine is slightly lower. Twin and sibling studies have not revealed a consistent mendelian pattern in either the classic or common form. Certain rare forms of migraine, such as familial hemiplegic migraine, appear to be monogenic disorders but the role of these genes, most of which code for ion channels, in all forms of migraine is still speculative.