title: Intracranial hypotension secondary to spinal arachnoid cyst rupture presenting with acute severe headache: a case report.
abstract: BACKGROUND
  Headache is a common presenting complaint and has a wide differential diagnosis. Clinicians need to be alert to clues that may suggest an underlying secondary aetiology. We describe a novel case of headache secondary to intracranial hypotension which was precipitated by the rupture of a spinal arachnoid cyst.
  
  
  METHODS
  A 51-year-old Indian female presented with sudden onset severe headache suggestive of a subarachnoid haemorrage. Investigations including a computed tomography brain scan, cerebrospinal fluid examination and a magnetic resonance angiogram were normal. The headache persisted and magnetic resonance imaging revealed bilateral thin subdural collections, a spinal subarachnoid cyst and a right-sided pleural effusion. This was consistent with a diagnosis of headache secondary to intracranial hypotension resulting from spinal arachnoid cyst rupture.
  
  
  CONCLUSIONS
  Spinal arachnoid cyst rupture is a rare cause of spontaneous intracranial hypotension. Spontaneous intracranial hypotension is a common yet under-diagnosed heterogeneous condition. It should feature significantly in the differential diagnosis of patients with new-onset daily persistent headache.
authors.affiliation: Department of Nephrology and General Medicine, North Middlesex University Hospital, Sterling Way, London, UK. peter.dupont@nmh.nhs.uk.
authors.forename: Wendy D
authors.initials: WD
authors.lastname: Jones
authors.forename: Makarand
authors.initials: M
authors.lastname: Kulkarni
authors.forename: K
authors.initials: K
authors.lastname: Ravishankar
authors.forename: Rudi
authors.initials: R
authors.lastname: Borgstein
authors.forename: Peter
authors.initials: P
authors.lastname: Dupont