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  1. Accurately identify the most likely etiology when patients present with a headache, through history, diagnostic tests, and appropriate patient findings on examination to enable the appropriate recommendation of effective treatment or referral to an appropriate provider.

  2. Use the knowledge of the pathophysiology, etiology, and common presentations of headaches as a primary symptom to review prescription orders for appropriateness and to accurately educate patients about their disease and its treatment.

Headaches are very common, with over 95% of patients suffering from at least one headache in their lifetime. Between 250 and 800 workdays/1000 patients in the U.S. are lost due to headaches. Headaches can occur as part of a systemic illness, such as influenza, or as a single symptom. The International Headache Society classification system (ICHD-2) has over 150 pages of concise diagnostic criteria for different types of headaches. In the literature, headaches have been classified in a variety of ways. Primary headaches, the most common, include tension-type headaches, migraine headaches, and cluster headaches. Secondary headaches are by definition all nonprimary headaches and include those due to meningitis, hypertensive emergencies, strokes, temporomandibular joint (TMJ) pain dysfunction syndrome, trauma related, and pseudotumor cerebri. Others have classified them by seriousness or urgency. Acute onset headaches are mostly secondary, are more serious, and can be life threatening, requiring immediate diagnosis and intervention. Chronic or recurrent headaches, which include all the primary headaches and have a much more benign prognosis.


The causes of headache are multiple and at times complex in pathophysiology. Infectious processes, vascular problems, malignancy, medications, trauma, metabolic disorders, musculoskeletal problems, dental problems, diagnostic procedures, and hypoxia all are etiologic causes of headaches. Even among primary headaches, the exact cause of some may not be known or the exact nature of the pathophysiology is unclear and potentially controversial.


There are several ways to classify headaches to facilitate diagnosis. For the purposes of this chapter, headaches will be organized as either primary or secondary.


The three main causes of a primary headache are tension-type headache, migraine headache, and cluster headache. While there are typical symptom patterns with each of the three primary headaches, initially it may be difficult to distinguish between severe tension headaches and some milder forms of migraines. Table 13.1 provides a quick guide to prominent features of the common primary headaches.

TABLE 13.1

Common Primary Headaches

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