RÉSUMÉ
We report the case of a 34-year-old man who was initially diagnosed with a tension-type headache after complaining of a headache and nausea. His headache worsened in severity and it was exacerbated on standing in the upright position. The patient was admitted to the hospital on suspicion of spontaneous low cerebrospinal fluid (CSF) pressure headache. Gadolinium-enhanced brain magnetic resonance imaging (MRI) revealed diffuse pachymeningeal enhancement, brain sagging, cerebellar tonsillar herniation, brainstem descent and a subdural hematoma. Successful emergency surgery was undertaken.<br>Spontaneous low CSF pressure headache syndrome is characterized by orthostatic headache, and if such a headache worsens, clinicians should consider a subdural hematoma, a life-threatening complication of this unusual disorder.