title: Acute Foramen Magnum Syndrome Following Single Diagnostic Lumbar Puncture: Consequence of a Small Posterior Fossa?
abstract: BACKGROUND
  Type I Chiari malformation (CMI) is a rare complication of lumbar cerebrospinal fluid (CSF) drainage that is usually reported after lumbar drain or lumboperitoneal shunt placement. It usually remains asymptomatic; however, even if it becomes symptomatic, symptoms are usually mild. There are only a few reports of acute foramen magnum syndrome following continuous lumbar CSF drainage, and acute foramen magnum syndrome after a single diagnostic lumbar puncture (LP) has not been previously reported. We encountered this catastrophic complication in one of our patient.
  
  
  METHODS
  A 30-year-old woman with a large supratentorial meningioma and associated asymptomatic CMI presented with holocranial headache. She underwent successful and uneventful excision of the tumor. However, she developed quadriplegia and respiratory arrest 48 hours following a diagnostic LP performed on postoperative day 9. She underwent urgent posterior fossa decompression after magnetic resonance imaging showed increased tonsillar impaction and swelling along with cervicomedullary compression. Postoperatively, she steadily improved and regained normal power after 3 months. Retrospective quantitative analysis of magnetic resonance imaging (MRI) revealed a small posterior fossa.
  
  
  CONCLUSIONS
  The association of intracranial tumors and lumbar CSF drainage with CMI is uncommon. The documentation of a small posterior fossa signifies the importance of both developmental (small posterior fossa) and acquired (intracranial tumor/lumbar CSF drainage) factors in pathogenesis of CMI. Although the extreme rarity of acute deterioration following a single LP does not warrant LP to be contraindicated in such patients, documentation of resolution of CMI with postoperative MRI before performing lumbar CSF drainage (whether therapeutic or diagnostic), might be helpful in avoiding this rare complication.
authors.affiliation: Department of Neurosurgery, All India Institute of Medical Sciences, New Delhi, India. Electronic address: aman_jagdevan@yahoo.co.in.
authors.forename: Amandeep
authors.initials: A
authors.lastname: Kumar
authors.affiliation: Department of Neurosurgery, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Mohit
authors.initials: M
authors.lastname: Agrawal
authors.affiliation: Department of Neurosurgery, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Surya
authors.initials: S
authors.lastname: Prakash
authors.affiliation: Department of Neuroradiology, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Shambanduram
authors.initials: S
authors.lastname: Somorendra
authors.affiliation: Department of Neurosurgery, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Pankaj Kumar
authors.initials: PK
authors.lastname: Singh
authors.affiliation: Department of Neuroradiology, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Ajay
authors.initials: A
authors.lastname: Garg
authors.affiliation: Department of Neurosurgery, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Manmohan
authors.initials: M
authors.lastname: Singh
authors.affiliation: Department of Neurosurgery, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Bhawani Shanker
authors.initials: BS
authors.lastname: Sharma
mesh_terms: D000328:Adult; D001139:Arnold-Chiari Malformation / Q000150:complications* / Q000000981:diagnostic imaging / Q000601:surgery; D065634:Cerebrospinal Fluid Leak / Q000000981:diagnostic imaging / Q000601:surgery; D005260:Female; D005539:Foramen Magnum / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008577:Meningeal Neoplasms / Q000150:complications* / Q000000981:diagnostic imaging / Q000601:surgery; D008579:Meningioma / Q000150:complications* / Q000000981:diagnostic imaging / Q000601:surgery; D019635:Neurosurgical Procedures / Q000379:methods; D013129:Spinal Puncture / Q000009:adverse effects*; D015898:Tomography Scanners, X-Ray Computed
keywords: Diagnostic lumbar puncture; Posterior cranial fossa volume; Supratentorial tumor; Type I Chiari malformation