Two cases of medically-refractory spontaneous orthostatic headaches with normal cerebrospinal fluid pressures responding to epidural blood patching: Intracranial hypotension versus hypovolemia and the need for clinical awareness.

The diagnosis of spontaneous intracranial hypotension or cerebrospinal fluid (CSF) hypovolemia syndrome requires a high index of suspicion and meticulous history taking, demonstration of low CSF pressure and/or neuroimaging features. A 31-year-old male, presented with subacute onset moderate occipital and sub-occipital headaches precipitated by upright posture and relieved on recumbency and neck pain for 2 years. There was no trauma, cranial/spinal surgery. Clinical examination was normal and CSF opening pressure and laboratory study were normal. Magnetic resonance imaging (MRI) brain showed thin subdural hygroma. Another patient, 41-year-old male presented with 1 month of subacute onset severe bifrontal throbbing orthostatic headaches (OHs). CSF opening pressure was normal. Contrast MRI brain showed the presence of bilateral subdural hygromas, diffuse meningeal enhancement, venous distension, sagging of the brain, and tonsillar herniation. We report two cases of "spontaneous OHs" with normal CSF pressures who were successfully treated with epidural blood patching after poor response to conservative management.