title: Clinical characteristics of exacerbations in Parkinson disease.
abstract: BACKGROUND
  Episodes of subacute worsening of motor function occur commonly in Parkinson disease (PD), but there has been surprisingly little research about the clinical characteristics of these exacerbations in the outpatient setting.
  
  
  METHODS
  Retrospective study of an established cohort of 120 outpatients with PD. Primary outcome measures were the frequency, causes, and outcomes of motor exacerbations. Statistical analysis was performed to compare baseline characteristics of subjects with subsequent exacerbations versus without subsequent exacerbations.
  
  
  RESULTS
  Over an 18-month period, 43 exacerbations occurred, affecting 30 of 120 subjects (25.0%). Infection was the single most frequent underlying cause, accounting for 11 of 43 (25.6%) exacerbations. Other common etiologies were anxiety (n=8), medication errors (n=6), poor adherence (n=6), medication side effects (n=3), and postoperative decline (n=3). Overall, 35 episodes (81.4%) were attributable to reversible or treatable causes. Most subjects recovered fully, but 10 (33.3%) experienced recurrent episodes, 5 (16.7%) suffered permanent decline, and 1 died. At baseline, subjects with exacerbations had a significantly longer median disease duration (7.8 vs. 5.7 y, P=0.003), lower Mini-Mental State Examination scores (27.0±3.3 vs. 28.6±1.6, P=0.02), higher modified Hoehn and Yahr scores (2.2±0.5 vs. 1.9±0.5, P=0.006), greater dopaminergic medication use (median, 750.0 vs. 395.0 levodopa equivalents; P=0.009), and a greater prevalence of motor complications (55.2% vs. 29.4%, P=0.01) than subjects without exacerbations.
  
  
  CONCLUSIONS
  Exacerbations are common in PD, associated with more advanced disease, and usually attributable to treatable secondary causes such as intercurrent infection. Increased recognition of these underlying causes may help to decrease morbidity, reduce health care costs, and optimize quality of care in PD.
authors.affiliation: Departments of Neurology and Neuroscience, Weill Cornell Medical College, New York, NY, USA.
authors.forename: Karen S
authors.initials: KS
authors.lastname: Zheng
authors.forename: Benjamin J
authors.initials: BJ
authors.lastname: Dorfman
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Christos
authors.forename: Nasim R
authors.initials: NR
authors.lastname: Khadem
authors.forename: Claire
authors.initials: C
authors.lastname: Henchcliffe
authors.forename: Panida
authors.initials: P
authors.lastname: Piboolnurak
authors.forename: Melissa J
authors.initials: MJ
authors.lastname: Nirenberg
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000978:Antiparkinson Agents / Q000627:therapeutic use; D005260:Female; D006801:Humans; D007980:Levodopa / Q000627:therapeutic use; D008297:Male; D008609:Mental Status Schedule; D008875:Middle Aged; D009068:Movement / Q000187:drug effects / Q000502:physiology*; D017063:Outcome Assessment, Health Care; D010045:Outpatients; D010300:Parkinson Disease / Q000150:complications* / Q000188:drug therapy / Q000523:psychology*; D011788:Quality of Life; D012189:Retrospective Studies; D012720:Severity of Illness Index
chemical_list: D000978:Antiparkinson Agents; D007980:Levodopa