title: Adult-onset seizures in a patient with Down syndrome and portosystemic shunt.
abstract: OBJECTIVE
  The prevalence of epilepsy in patients with Down syndrome (DS) is 5-13%, which is higher than the prevalence in the general population. Transient hyperammonemia is often observed following seizure, but it typically resolves within a day. Here, we describe the case a 37-year-old woman who had DS and a history of adult-onset epilepsy and was admitted to our hospital with recurrent seizures. After admission, her ammonia levels fluctuated without any apparent cause, and dynamic computed tomography revealed a portosystemic shunt. The findings suggest that her seizures possibly precipitated from hyperammonemia secondary to a portosystemic shunt, and we reviewed the relevant literature.
  
  
  METHODS
  We conducted PubMed, Web of Science, and EMBASE searches without language restrictions for articles published between 1970 and February 2013.
  
  
  RESULTS
  In addition to the present case, 7 cases were ultimately included in this review. Four patients were newborns, 2 patients were 1 month old, and 1 patient was 3 years old. No adult cases were described until now.
  
  
  CONCLUSIONS
  Adult patients with DS diagnosed with epilepsy are not routinely assessed for portosystemic venous shunts. Measuring ammonia levels in patients with DS the day after admission would help detect portosystemic shunts, even if the patients have been previously diagnosed with epilepsy.
  
  
  CONCLUSIONS
  If ammonia levels fluctuate without any apparent cause after seizure, dynamic computed tomography should be performed, especially for patients with DS, whether or not they have been previously diagnosed with epilepsy.
authors.affiliation: Department of Emergency and Critical Care Medicine, The University of Tokyo Hospital, Japan. Electronic address: inokuchir-icu@h.u-tokyo.ac.jp.
authors.forename: Ryota
authors.initials: R
authors.lastname: Inokuchi
authors.affiliation: Department of Emergency and Critical Care Medicine, The University of Tokyo Hospital, Japan.
authors.forename: Kensuke
authors.initials: K
authors.lastname: Nakamura
authors.affiliation: Department of Emergency and Critical Care Medicine, The University of Tokyo Hospital, Japan.
authors.forename: Naoaki
authors.initials: N
authors.lastname: Mizuno
authors.affiliation: Department of Health Policy and Technology Assessment, National Institute of Public Health, Japan.
authors.forename: Hajime
authors.initials: H
authors.lastname: Sato
authors.affiliation: Department of Emergency and Critical Care Medicine, Ohta Nishinouchi Hospital, Japan.
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Shinohara
authors.affiliation: Department of Emergency and Critical Care Medicine, The University of Tokyo Hospital, Japan.
authors.forename: Takehiro
authors.initials: T
authors.lastname: Matsubara
authors.affiliation: Department of Emergency and Critical Care Medicine, The University of Tokyo Hospital, Japan.
authors.forename: Kent
authors.initials: K
authors.lastname: Doi
authors.affiliation: Department of Emergency and Critical Care Medicine, The University of Tokyo Hospital, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Ishii
authors.affiliation: Department of Emergency and Critical Care Medicine, The University of Tokyo Hospital, Japan.
authors.forename: Masataka
authors.initials: M
authors.lastname: Gunshin
authors.affiliation: Department of Emergency and Critical Care Medicine, The University of Tokyo Hospital, Japan.
authors.forename: Susumu
authors.initials: S
authors.lastname: Nakajima
authors.affiliation: Department of Emergency and Critical Care Medicine, The University of Tokyo Hospital, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Yahagi
mesh_terms: D000328:Adult; D000367:Age Factors; D004314:Down Syndrome / Q000150:complications*; D005260:Female; D006801:Humans; D022124:Hyperammonemia / Q000150:complications / Q000175:diagnosis*; D011169:Portal Vein / Q000002:abnormalities*; D012640:Seizures / Q000150:complications / Q000175:diagnosis*; D016157:Vascular Fistula / Q000150:complications / Q000175:diagnosis*; D014682:Vena Cava, Inferior / Q000002:abnormalities
keywords: Down syndrome; Epilepsy; Hyperammonemia; Portosystemic shunt; Seizure