Acute Deterioration in a Patient with Bilateral Chronic Subdural Hematomas Associated with Intracranial Hypotension Treated with an Epidural Blood Patch

background Intracranial hypotension due to cerebrospinal fluid (CSF) leak is often associated with secondary chronic subdural hematoma (CSDH). Although epidural blood patch (EBP) treatment for the CSF leak site has been reported to result in spontaneous regression of the CSDH in most cases, it is still debatable whether blocking CSF leak first in the patients with intracranial hematoma is always safe. Case Description A 72-year-old woman presented with orthostatic headache after a head injury and was diagnosed with intracranial hypotension. Computed tomography myelography and radioisotope cisternography failed to reveal the CSF leak point. The overflow leak test, a novel diagnostic method for intracranial hypotension, revealed a leakage at the cervical spine. Bilateral CSDHs were also observed by a computed tomography scan of the head. We performed EBP at the cervical spine and anticipated subsequent regression of the CSDH by normalizing intrathecal pressure. However, the patient became delirious the morning after EBP, and an emergency burr hole trepanation was performed. The patient's consciousness fully recovered, and her orthostatic headache improved as well. Conclusions This case presentation demonstrated that in the case of intracranial hypotension with secondary CSDH, performing EBP and waiting for subsequent spontaneous regression of CSDH are not necessarily safe. Immediate burr hole trepanation should be prepared for the subsequent rapid symptomatic change of the CSDH after EBP.