Chapter 36: Headache

LEARNING OBJECTIVES

INTRODUCTION

Headache is a common medical complaint with approximately 50% of the adult population experiencing at least one headache per year.¹ Headaches can be considered primary or secondary conditions. Primary headaches, even when persistent or recurrent, are usually a benign condition. Secondary headaches are caused by an underlying medical disorder and may need medical emergencies. Primary headache syndromes are the focus of this chapter. The International Headache Society (IHS) classifies primary headaches as migraine, tension-type, or cluster and other trigeminal autonomic cephalalgias.² Patients may seek headache care from multiple providers; so all clinicians should be familiar with the various types of headache; clinical indicators suggest the need for urgent medical attention or specialist referral, and nonpharmacologic and pharmacologic options for treatment.

EPIDEMIOLOGY OF HEADACHE DISORDERS

Migraine Headache

Migraine is a primary headache disorder with an estimated 3-month prevalence rate in the United States of 14.2% in adults over 18 years. Prevalence is higher in females at 19.1% compared to males at 9%. The highest prevalence is in women 18 to 44 years of age at 23.5%.³ In pediatric patients, there is also a higher incidence in girls after the age of 10.⁴ The difference in gender distribution is thought to be due to hormonal differences.

Tension-Type Headache

Tension-type headache (TTH) is the most common primary headache disorder and can be further divided into episodic or chronic.² The term TTH is used to describe all headache syndromes in which sensitization to pericranial nociception, known as noxious stimuli, is the most significant factor in the pathogenesis of pain.⁵ Overall reported prevalence of TTH is approximately 86%, and incidence is more common in women than men. Episodic TTH is the most common type, followed by frequent episodic TTH and chronic TTH. Incidence of TTH increases until approximately age 40, then incidence begins to slowly decline.⁶ Environmental factors, as opposed to genetic predisposition, play a central role in the development of TTH. The mean frequency of attacks is 3 days per month in episodic disorders; episodic is defined as less than 15 attacks in a 1-month period with no pattern, and chronic TTH is defined as 15 or more attacks in a 1-month period for at least 6 months.²

Cluster Headache and Other Trigeminal Autonomic Cephalalgias

Cluster headache disorders are severe primary headache syndromes and uncommon.^...