Hypnic headache constitutes one rare type of primary short-lasting headache related to sleep. It was first characterized by Raskin in 1988.1 Hypnic headache is not included in the classification of the International Headache Society,2 although diagnostic criteria have been proposed.3
Hypnic headache constitutes one rare type of primary short-lasting headache related to sleep.
The authors describe two cases of hypnic headache that had a very good response to lithium carbonate. Although these two cases do not fulfill the proposed criteria for hypnic headache, as the pain was not bilateral, and, in case 2, it had a longer duration than previously described, we believe that the very good response to lithium carbonate favors this diagnosis.
We believe that it is important to consider a diagnosis of hypnic headache because of the remarkable response to lithium carbonate shown by some patients with this condition.
A 65-year-old woman went to the hospital emergency department because of severe headaches that had started 1 week prior, occurring every night and awakening her. The pain was left hemicranial, lasted 60 minutes, and was not associated with any other changes. The physical examination and erythrocyte sedimentation rate (ESR) were normal. The patient recently had a CT brain scan without any changes. The patient was treated with 50 mg of indomethacin at bedtime, which she took for 5 nights with a decrease in the intensity of pain, but it continued to awaken her each night. After this ineffective therapy, she started taking 400 mg of lithium carbonate at bedtime and became headache-free after 7 days. The medication was maintained for 2 months and then slowly tapered. The headache recurred 5 months later, but disappeared again 2 days after resuming lithium carbonate.
A 68-year-old man was sent to the neurology clinic because of epileptic seizures and a history of poor compliance to therapy with carbamazepine. In addition to seizures, which could be easily controlled by a regular dose of the anticonvulsant, he gave a past history of headaches that started about 4 years previously. These were severe in intensity, waking him up every night, starting in the left temporal area and spreading over the whole head, lasting 120 minutes, and with no associated changes. He experienced some relief with 600 to 900 mg of clonixine and the local application of ice. The physical examination did not reveal any abnormalities. The ESR was normal, and magnetic resonance imaging showed only signal changes in the white matter, suggesting ischemic lesions. The patient started taking 400 mg of lithium carbonate before going to bed, becoming symptom-free soon after starting this therapy. After 2 months, the lithium was slowly withdrawn, with recurrence of headache a few days later. He restarted the medication and was symptom-free soon thereafter.
Both cases have much in common with the patients originally characterized by Raskin.1 Both were more than 65 years old, and they had a headache that awakened them during nighttime sleep, without any associated dysautonomia, without a causal organic disease, and with a dramatic response to lithium carbonate.
However, these two patients presented a few particularities. Notably, the pain was unilateral, and, in case 2, it lasted for more than 60 minutes. Similar findings have been reported by Dodick et al4 in other patients.
The benefit of prophylactic therapy with lithium carbonate is classic, although caffeine,4,5 flunarizine,5 and indomethacin6 have also been efficacious in some patients. We tried indomethacin in case 1 without any striking result.
Hypnic headache is an important cause of benign headache in the elderly. Recognition of this type of headache should be promoted as there are efficacious prophylactic therapies which can improve the quality of life.