Headache is a nearly universal symptom. As an example of the prevalence of headache, a study of 410 patients who had visited a primary care internal medicine practice found that headache was the fourth most common symptom and was exceeded only by fatigue, back pain, and dyspnea.1 In an early study of more than 1 million unselected individuals from the general population, headache was the single most common current symptom and was reported by 39% of men and 56% of women.2 As physicians, nearly all of us have had personal experience with headache and can understand the headache descriptions that we hear from our patients. Chapter 27 elegantly details the prevalence of this common symptom and of common primary headache syndromes. Primary headaches are those without a pathologic basis.3–5 These are benign recurring headaches of unknown cause. The most common primary headache syndromes are migraine, tension-type headache (TTH), and cluster headache. Secondary headaches are caused by an underlying pathologic cause.
When faced with the large numbers of patients who seek medical evaluation for headache, clinicians seek to identify the rare patient with a serious headache from the rest whose headaches are benign in nature. Two general approaches assist this effort. First, one must learn the warning symptoms and signs that suggest a pathologic cause for headache. Many published reviews have offered such advice.3,6,7 A complementary approach is to learn to confidently diagnose benign primary headache syndromes through careful history taking and the systematic application of established diagnostic criteria. Primary headaches are clinical diagnoses that are based on history taking alone. With the exception of the occasional persistence of a partial Horner's syndrome among asymptomatic patients with a history of cluster headaches, the physical examination of a patient with primary headaches is normal during headache-free intervals.
The most commonly used criteria are the International Classification of Headache Disorders, second edition (ICHD-2). The use of these criteria, most recently updated in 2004, helps to identify uniform populations of patients for research and epidemiologic studies. The criteria themselves are, however, complicated, not easily committed to memory, and may be unnecessarily restrictive in the daily clinical care of patients.
When evaluating individual patients with headache, clinicians will benefit from understanding which historical features are most useful in establishing or excluding a particular primary headache diagnosis. This chapter reviews and summarizes published clinical series of patients with migraine, TTH, and cluster headache, to determine the sensitivity, specificity, and likelihood ratios of individual historical features.
IS THIS AN OLD OR NEW HEADACHE?
Clinicians may initially classify all headaches as either old or new. Old headaches are similar to those that have occurred repeatedly over time. Primary headaches are old headaches. New headaches are either headaches of recent onset or those that represent a change in the character or pattern of an old ...