Interictal and periictal headache in patients with epilepsy.

OBJECTIVE

Interictal headache (IIH), and in particular migraine, is considered a relevant co-morbidity in epilepsy; however, available data are ambiguous. Periictal headache (PIH) displays a frequent ancillary burden to seizures, but identification of unequivocal predictors is still elusive.

METHODS

All patients (≥ 18 years) with epilepsy or unprovoked seizures seen in a tertiary epilepsy outpatient clinic underwent a semi-structured interview regarding occurrence and characteristics of IIH and PIH. Clinical variables in patients with and without IIH and PIH and seizure types with and without PIH were compared.

RESULTS

Out of 201 patients, 56.2% reported headache, IIH occurred in 34.3% and 10.9% suffered from migraine. PIH was reported by 35.3%, occurring preictally in 16 and postictally in 61 cases. PIH character was migrainous in 26.8% and tension-type headache-like in 62%, mean severity was 6.1 ± 2.2 cm. PIH was treated analgetically by less than 40% of patients, only 11% sought specific medical advice. Predictors were low age at epilepsy onset (OR 0.963, 95% CI 0.945-0.981, P < 0.0001), antiepileptic drug (AED) polytherapy (OR 1.943, 95% CI 1.046-3.612, P = 0.036) and generalized tonic-clonic seizures (P < 0.0001).

CONCLUSIONS

In patients with epilepsy, IIH, and particularly migraine, is less common than expected, challenging the widely held concept of co-morbidity of the two conditions. PIH is frequent, severe and undertreated. Predictors include low age at epilepsy onset, AED polytherapy and tonic-clonic generalized seizures. Physicians should ask for PIH and offer specific analgesic treatment. To confirm these findings, future studies with a prospective approach implementing a headache and seizure diary should be performed.