Investigators at Robert Debre Hospital and Paris Diderot University, Paris, France, and Basildon University Hospital, Essex, UK, conducted a prospective study of 101 children aged 6-18 years presenting to the ED of a tertiary hospital with moderate to severe headache and focal neurologic deficit with focal brain disturbance. Children with a history of trauma, fever, or neurosurgical intervention were excluded. After one-year follow-up, the final diagnosis was primary headache in 66% cases (94% migraine with aura), and 34% received a final diagnosis of secondary headache (76.5% with focal epilepsy). Children with bilateral localization of pain had a higher likelihood of having secondary headache (p < 0.001).
In the secondary headache group, 26 children had a seizure: 14 had benign childhood occipital epilepsy (Panayiotopoulos syndrome), 5 had temporal lobe epilepsy (2 with dysembryoplastic neuroepithelial tumor), 4 had epilepsy with centrotemporal spikes, and 2 had occipital and 1, parietal lobe epilepsy. Other secondary headaches were associated with arterial ischemic stroke (2 cases), cerebral venous sinus thrombosis (2), arteriovenous malformation (2), and 2 with intracranial neoplasm (1 astrocytoma, 1 medulloblastoma). The headache lasted longer than 24 hours in 15 of the primary group and 8 of the secondary headache group. Neurologic deficit was no longer present by 1 hour after initial onset in 72 patients (71.3%).
MRI disclosed brain disorders related to the acute headache in 10 of 78 children (12.8%). In patients suspected of having epilepsy, an awake and asleep EEG was performed during the ED admission in 15 patients (14.9%) of whom 9 had epilepsy, and within 1 week in 47 patients (46.5%), of whom 26 were considered to have experienced a seizure. 
COMMENTARY. The 2nd edition of the International Classification of Headache Disorders (2004) (ICHD-2) separates headache into 4 categories of primary headache (migraine, tension-type headache, cluster headache, other trigeminal autonomic cephalgias), and other unclassified primary headaches, and 8 categories of secondary headache [2, 3]. Secondary causes of headache are considered in the following situations :
- escalating frequency and/or severity of headache
- change of frequency and severity of headache
- headache associated with fever
- headache accompanied by seizures
Comorbidity of headache and epilepsy. The ICHD-2 defines 3 kinds of association of headache and epileptic seizure: (1) migraine-triggered seizure or ictal epileptic headache, (2) hemicrania epileptica (very rare variant of epileptic headache), and (3) pre-ictal headache . Headache and epilepsy are a common comorbidity in childhood and occur mostly in children older than 10 years with idiopathic epilepsy .
Among 100 children with chronic recurrent headaches treated in neurology practice, 15% had a history of epileptic seizures. EEG showed epileptiform discharges in 18%. Headaches were diagnosed as migraine in 42% and tension headaches in 18%. A trial of antiepileptic medication controlled headaches in 77% of 30 children with migraine, but a positive response was unrelated to an abnormal EEG. Beneficial response rates were 61% and 88% in 13 with abnormal and 17 with normal EEGs, respectively. Migraine patients with normal or abnormal EEGs were benefited. An abnormal EEG and response to AED are insufficient criteria for a diagnosis of epileptic headache .