Bath-related thunderclap headache: a study of 21 consecutive patients

We consecutively recruited 21 patients (all women, mean 54 +/- 8 years) with bath-related thunderclap headache (BRTH). Thirteen of them were in menopause, two had just ceased hormonal therapy, and one was at 3 months postpartum. Bathing was the initial trigger for thunderclap headaches in nine patients (43%). Many patients (n = 15, 71%) had other non-bath-related attacks. Most patients (n = 18, 86%) reported that the headache occurred immediately when water was sprayed over their body, with warm water (52%) as the most common. During the disease course [mean 14 days (6-34)], the mean number of BRTH was 5.1 +/- 3.6 attacks. Nineteen patients (90%) changed bathing habits to prevent attacks. Thirteen patients (62%) had magnetic resonance angiography vasoconstrictions, and two of them (15%) developed reversible posterior encephalopathy. None of the patients without vasoconstrictions had this complication. Nimodipine was effective in stopping further attacks in 84% (16/19) treated patients. No relapse was reported at a mean follow-up of 30 months. BRTH occurred exclusively in women and predominantly in middle age. Deficiency or fluctuation of female sex hormones may play a role. About 60% patients showed cerebral vasospasms, fulfilling the diagnosis of reversible cerebral vasoconstriction syndrome and indicating a risk of posterior encephalopathy.