title: Uncovering clinical and radiological associations of triphasic waves in acute encephalopathy: a case-control study.
abstract: OBJECTIVE
  Triphasic waves (TWs) are archetypal waveforms seen on electroencephalography (EEG) in some forms of encephalopathy. Their particular underlying pathological substrates are largely unexplored. This case-control study was designed to identify and quantify specific clinical and neuroradiological associations underlying TWs and to determine if TWs predicate outcome.
  
  
  METHODS
  From 2004 to 2012, adult encephalopathic patients with TWs (cases) were matched 1:1 with encephalopathic patients without TWs (controls) by Glasgow Coma Scale (GCS) and the frequency range of EEG background activity. Clinical characteristics, neuroimaging and outcomes were assessed.
  
  
  RESULTS
  The mean age of 190 patients (95 with and 95 without TWs) was 66.6 years (±15.6). In multivariable analyses, patients with TWs had significantly higher odds for liver insufficiency [odds ratio (OR) = 8.10, 95% confidence interval (CI) 1.98-33.08], alcohol abuse (OR = 3.65, 95% CI 1.25-10.63), subcortical brain atrophy (OR = 2.82, 95% CI 1.39-5.71) and respiratory tract infections (OR = 1.28, 95% CI 1.01-4.71). With each additional independent predictor, the odds increased for the occurrence of TWs (1 predictor, OR = 2.40, 95% CI 1.16-5.13; ≥2 predictors, OR = 9.20, 95% CI 3.27-25.62). Mortality was 15% and tended to be higher in patients with TWs (19% with vs. 11% without TWs).
  
  
  CONCLUSIONS
  Alcohol abuse, liver insufficiency, infections and subcortical brain atrophy were independently associated with TWs in patients matched for clinical and EEG features of encephalopathy. These associations strengthen the hypothesis that TWs evolve from an interplay of pathological neurostructural, metabolic and toxic conditions. When matched for EEG background activity and GCS, TWs were not associated with death.
authors: Division of Neurosciences Critical Care, Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Neurology, Johns Hopkins Bayview Medical Center, Baltimore, MD, USA.
authors: R
authors: R
authors: Sutter
authors: P W
authors: PW
authors: Kaplan
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000503:physiopathology*; D001927:Brain Diseases / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology*; D058256:Brain Waves / Q000502:physiology*; D016022:Case-Control Studies; D004569:Electroencephalography; D005260:Female; D015600:Glasgow Coma Scale; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D015898:Tomography Scanners, X-Ray Computed
keywords: clinical characteristics; encephalopathy; neurocritical care; neuroimaging; outcome; subcortical atrophy; triphasic waves; white matter disease