Abstracts

Hepatic encephalopathy (HE) encompasses a wide spectrum of neuropsychiatric disturbances, usually reversible, observed in patients with significant liver dysfunction. In order to better asses the electroencephalographic changes found in patients with chronic hepatic failure submitted to liver transplantation (LT) at the Servi[Ccedil]o de Transplante Hepatico do Hospital de Clinicas da UFPR, Curitiba, the authors prospectively followed 20 patients, the youngest one being 15 years old, who had all underwent LT. The variables included physical examination, classification of HE and liver disease, electroencephalogram (EEG) and assessment of cognitive functions with the following neuropsychological tests (NPTS): Mini-Mental State, Trail Making Test Part B, Digit Span subtest used in the Wechsler Adult Intelligence Scale [ndash] Revised (WAIS-R), Word Fluency (FAR) and Category Fluency and the Clock Drawing Test. The severity of HE was graded according to the findings of the physical examination, neuropsychological testing and EEG. Subclinical HE was diagnosed when the EEG disclosed a diffuse slowing of background activity or at least two neuropsychological tests were abnormal in the absence of clinical findings. EEG was prospectively evaluated, with a baseline recording in the pre-transplantation period (pre-LT) and 30 and 90 days after the transplant (post-LT). Mean posterior baseline rhythm frequency (PBRF) was of 8.8 [plusmn] 1.9 Hz in the pre-LT period, 9.8 [plusmn] 1.7 Hz at 30 days post-LT and 9.9 [plusmn] 1.7 at 90 days post-LT and this increase in the PBRF was considered significant (p[gt] 0,0001). Mean PBRF in the transplantation group was lower than in the control group. Nine patients (45.0%) had a diffuse slowing of background activity in the EEG in the pre-LT period, with 4 patients (44.4%) presenting with a IIA slowing, 4 patients (44.4% with a IIIA slowing and one with a IIIC slowing. Fifteen patients were evaluated 30 days after LT, and 3 of them (20.0%) had a slow EEG: 1 with a IIA slowing, 1 with a IIIA and one with a IIIB. EEG recording of 14 patients 90 days after LT disclosed a IIIA slowing in just one patient. All the patients who presented with slowing in their initial EEG had a significant improvement of background activity following LT (p[gt] 0, 0001). Three patients also had triphasic waves in their EEGs. The diagnosis accuracy of PBRF, background slowing and the occurrence of triphasic waves were evaluated in comparison with NPTS as the gold standard for the diagnosis of HE. As a result, EEG parameters had a good specificity and positive predictive values (PPV), with low sensitivity and negative predictive values (NPV). Final assessment of improved HE in the post-LT period considered NPTS as the gold standard, but also demonstrated that EEG abnormalities have high specificity and PPV, but low sensibility and NPV.