Hypnic headache: a descriptive study of 25 new cases in Brazil.

Our aim was to show the clinical characteristics of 25 patients with hypnic headache. We reviewed the medical records of 11,360 patients who complained of headache and selected those with hypnic headache, according to the criteria of the International Classification of Headache Disorders-2. Twenty-five patients (20 women and 5 men) were diagnosed with hypnic headache. The average age at the headache onset was 65.6 ± 11.4 years (95% CI 61.1-70.1), ranging from 51 to 89 years. The diagnosis of hypnic headache was made 3.0 ± 2.7 years (95% CI 1.9-4.0) after the headache started. Fourteen patients (56.0%) were awakened between 4:00 and 6:00 a.m. The headache lasted for more than 2h in 16 (64.0%) patients. The headache was bilaterally localized (16/25; 64.0%), had a dull character (18/25; 72.0%) and a moderate intensity (17/25; 68.0%). The frequency was greater than 15 days per month (14/25; 56.0%). Associated symptoms were reported by 7 patients: nausea (71.4%) and phonophobia (28.6%). There was successful treatment with lithium carbonate in 16/22 (72.7%) of the patients. Hypnic headache occurs exclusively during sleep in the elderly and especially in women. Lithium is an effective drug for its treatment.