Long‐Term Outcomes and Clinical Characteristics of Hypnic Headache Syndrome: 40 Patients Series From a Tertiary Referral Center

Objective Hypnic headaches (HHs) are unique because of late life onset and characteristic periodic nocturnal awakening. We retrospectively identified 40 cases at a tertiary headache referral center over the course of 6 years and assessed response to conventional treatments. Methods This was a retrospective study in which patients were identified using primary and secondary ICD-9 diagnostic codes of HHs (339.81) from October 2008 until December 2014 using the International Classification of Headache Disorders II and III-beta criteria for diagnosis. Baseline characteristics were collected. Primary outcome was response to medications divided into 4 categories: complete response (headaches completely gone), moderate response (≥50% decrease in frequency), partial response (<50% decrease in frequency), no response. Results Forty (40) patients (80% females) were identified with HHs, and mean follow-up was 929 days (range 42-2555). Average age of headache onset was 62 years (range 44-86). Twenty (50%) patients had previous history of migraine, 5% had bilateral cranial autonomic features, and 40% underlying sleep abnormalities. The average duration per day and frequency per month of headaches were 186 minutes (range 30-720 minutes) and 21 days (range 5-30), respectively. Among 15 different medications tried, the best response was seen with lithium (7/10 [70%] complete response and 2/10 [20%] moderate response). With caffeine, there was a complete response in 6/21 (28%) and moderate response in 9/21 (43%) subjects. A telephone follow-up survey revealed that 5 patients in the bedtime caffeine group also benefited from taking a caffeinated drink at the time of awakening. Conclusions HH is an infrequent primary headache disorder that can present with cranial autonomic features. It can persist for years in the elderly. Lithium appeared to be the most effective treatment option, followed by caffeine at bedtime. Caffeine ingestion on awakening with an HH also demonstrated benefit. Cervicogenic headaches in the elderly and presence of active migraine are major confounders in the diagnosis of HHs.