INTRODUCTION AND EPIDEMIOLOGY
Headache is pain in the scalp and cranium. Headaches in children can be mild, refractory, or life threatening, and can represent an acute, subacute, or chronic process. Headaches are broadly classified as primary headache disorders, which are intrinsic to the nervous system, and secondary headaches, which are caused by another condition such as trauma, infection, or intracranial or systemic disease (see later section, “Headache Classification”).
Headaches are common in children, with an increasing prevalence through childhood and a peak in adolescence. The mean prevalence of headache in childhood is 58.4%, with a range of 24% to 90%, and 17% of children in the United States reported frequent or severe headaches in the past year.1-3 Headache prevalence is similar in girls and boys prior to adolescence, but after puberty, they are more prevalent in girls. Overall, primary headache disorders are more common than secondary headaches, and migraine and tension-type headaches are most common.4,5 The peak incidence of migraine is earlier for boys (10 to 11 years) than girls (12 to 14 years), and migraine with aura starts 3 to 5 years earlier than migraine without aura in both sexes.6 Tension-type headache has a mean age of onset of 7 years and is more common in girls.7 The estimated overall prevalence of migraine in childhood is 3.76% to 18%, and the overall prevalence of tension-type headache is 10% to 25%.7-10
Frequent or sustained headaches have a significant impact on children and their families, contributing to school absenteeism and missed parental work, and may even induce behavioral disturbances.11-13 Migraine headaches are among the top five causes of years lost to disability according to the World Health Organization,14 and children with migraines experience similar impact on quality of life as those with cancer or juvenile arthritis.12,15 There is an association between chronic headache and psychiatric comorbidity among children.16-18
Headaches compose about 1% to 2% of all ED visits among children, and in the ED setting, secondary headaches are more commonly diagnosed than primary headaches.2,19-22 Infectious etiologies such as upper respiratory tract infection are the most common cause of secondary pediatric headache in the ED, whereas migraine is the most common primary headache disorder diagnosed in this setting.2,19-21,23-25 There appears to be some seasonal variation in ED visits for headache, with peaks in September and January and lower visit rates in the spring and summer months.26-28
The pathophysiology of headaches is complex and varies according to cause. The cranium, most of the overlying meninges, brain, ependymal lining, and choroid plexus do not possess pain receptors. Extracranial pain may arise from cervical nerve roots, cranial nerves, or extracranial arteries, and intracranial pain may arise from intracranial venous, arterial, or dural structures. Cranial nerve or root ...