Objective.—To describe a new type of headache induced by water deprivation.
Background.—Two medical students experienced headache over the previous 7 (C.A.K.) and 9 (J.M.S.) years when deprived of drinking water. In a tutorial on headache, they mentioned this precipitant, not recognized by the tutor (J.N.B.) or described in the medical literature. Dialysis and post-alcohol headaches are widely attributed to dehydration, but simple water deprivation has not been documented as a headache precipitant.
Methods.—Family members, colleagues, and acquaintances were asked whether they experienced a headache when deprived of fluids. If they had, information was obtained regarding the location and quality of the headache, whether activity or posture influenced the pain, and what amount of fluid and time was needed to relieve symptoms.
Results.—Approximately 1 in 10 interrogated subjects experienced water-deprivation headache, aching in the majority and accentuated by head movement, bending down, or walking. The 34 subjects were divided into 2 groups according to the time taken to relieve the headache by drinking water: total relief within 30 minutes by drinking 200 to 1500 mL (mean, 500) occurred in 22 subjects, and within 1 to 3 hours by drinking 500 to 1000 mL (mean, 750) in 11 subjects; 1 subject required sleep in addition to fluid intake. Surprisingly, the Internet revealed many references to water deprivation inducing headaches.
Conclusions.—Water-deprivation headache is common, recognized by the public, but not described in the medical literature. Here we delineate it as a primary headache, postulating that the pain arises from the meninges; that the brain is also involved is indicated by impaired concentration and irritability, although not studied in detail in this preliminary survey. We speculate that water deprivation may play a role in migraine, particularly in prolonging attacks. Further studies of serum osmolality could prove illuminating.