[A case of bilateral chronic subdural hematoma due to spontaneous intracranial hypotension without orthostatic headache].

We herein present a case of bilateral chronic subdural hematoma(bilateral CSDH)caused by spontaneous intracranial hypotension(SIH)without orthostatic headache. A 67-year-old male patient with mild head injury suffered from a chronic, non-postural headache. Computed tomography of the brain showed bilateral CSDH. The hematomas were surgically evacuated using a closed drainage method. His headache immediately disappeared, but it recurred after 2 weeks. We further performed hematoma irrigation;however, his neurological status deteriorated with the development of pneumocephalus. Magnetic resonance imaging with gadolinium-DTPA showed diffuse pachymeningeal enhancement. His cerebrospinal fluid pressure was 3cmH₂O, and radioisotope cisternography revealed cerebrospinal fluid leakage at the level of the cervicothoracic transition. No recurrence was found after 6 weeks of horizontal bed rest. The possibility of SIH should be considered in patients with CSDH, especially bilateral CSDH, even in elderly patients with a history of mild head trauma, and absence of orthostatic headache. Closed drainage method may be preferable in cases where surgical treatment is used.