Spontaneous intracranial hypotension: Two cases including one treated with epidural blood patch.

Spontaneous intracranial hypotension (SIH) is characterized by orthostatic headache (OH), low cerebrospinal fluid (CSF) pressure, and diffuse pachymeningeal gadolinium enhancement (DPME). We present here the case studies of two patients. One patient demonstrated a CSF leak in the mid-thoracic region, and recovered completely with conservative treatment. The other patient in whom leak could not be demonstrated, developed dementia, rapidly worsening encephalopathy, and became comatose, necessitating urgent epidural blood patch (EBP) with 25 cc of autologous blood, after which immediate and complete symptomatic relief was obtained. A second EBP was required a few days later and also provided complete and sustained clinical benefit, without subsequent recurrence. Both patients had OH and showed bilateral subdural fluid collections, DPME and "sagging" of brain on MRI. A high index of suspicion, recognizing the orthostatic nature of headache, and typical findings on contrast enhanced MRI should point to the diagnosis of SIH. EBP can be effective treatment in patients unresponsive to conservative measures.