Reversible deep brain swelling causing REM behavior disorder

A 65-year-old woman presented with chronic lingering headache and REM sleep behavior disorder (RBD). Head MRI (figure) showed spontaneous intracranial hypotension (SIH) with deep brain swelling (DBS),(1) and CSF opening pressure was low. She was treated with lumbar epidural blood patch. Within 3 months, she became asymptomatic with improvement of brain sagging. Since SIH with DBS is related to brain sagging with deformity of the diencephalon and midbrain and since focal brain lesions may cause RBD,(2) distortion and dysfunction of REM sleep circuits in this patient may be caused by DBS. RBD expands the clinical spectrum of SIH.