title: Acute Presentation of Chiari I Malformation with Hemiparesis in a Pediatric Patient.
abstract: BACKGROUND
  Chiari I malformation (CM-I) is defined by cerebellar tonsillar herniation through the foramen magnum. Patients typically present with chronic complaints, including headache, dizziness, and numbness, although there are few reports in the literature of pediatric patients presenting acutely with neurological deficit caused by CM-I. We report a child who presented acutely with hemiparesis and magnetic resonance imaging findings consistent with CM-I and spinal cord edema.
  
  
  METHODS
  A 3-year old boy with normal development presented with difficulty walking and increased drooling. His mother stated he was running into objects and had balance issues for several days. Neurological examination showed ataxia with falling to the right after a few steps and weakness of the right arm and leg. His medical history was remarkable only for mild asthma, although he had recently been treated for an upper respiratory viral infection. Computed tomography of the head demonstrated no brainstem mass. Magnetic resonance imaging of the head and cervical spine showed tonsillar ectopia approximately 2 cm below the craniocervical junction with increased T2 signal in the spinal cord from C1 to C3 consistent with syringomyelia and cord edema. The patient underwent suboccipital craniectomy with removal of the posterior arch of C1 and dural patch graft. His postoperative course was unremarkable, with complete resolution of his symptoms at his 1-month follow-up visit.
  
  
  CONCLUSIONS
  This case highlights an unusual presentation of CM-I with neurological deficit related to spinal cord edema, possibly precipitated by the "water-hammer" effect of this patient's coughing fits. Providers should be aware of the acute presentations of CM-I.
authors.affiliation: University of Rochester School of Medicine & Dentistry, Rochester, New York, USA.
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Miranda
authors.affiliation: Department of Neurosurgery, University of Rochester Medical Center, Rochester, New York, USA. Electronic address: Kristopher_Kimmell@urmc.rochester.edu.
authors.forename: Kristopher T
authors.initials: KT
authors.lastname: Kimmell
authors.affiliation: Department of Neurosurgery, University of Rochester Medical Center, Rochester, New York, USA.
authors.forename: Howard J
authors.initials: HJ
authors.lastname: Silberstein
mesh_terms: D000208:Acute Disease; D001139:Arnold-Chiari Malformation / Q000150:complications / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery*; D001259:Ataxia / Q000209:etiology; D002675:Child, Preschool; D003399:Craniotomy; D004487:Edema / Q000209:etiology* / Q000503:physiopathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009460:Neurologic Examination; D019635:Neurosurgical Procedures / Q000379:methods*; D010291:Paresis / Q000209:etiology* / Q000503:physiopathology; D013118:Spinal Cord Diseases / Q000209:etiology* / Q000503:physiopathology; D016896:Treatment Outcome
keywords: Acute; Chiari I malformation; Hemiparesis; Pediatric