Screening for minimal hepatic encephalopathy among asymptomatic drivers with chronic liver disease

Abstract

Background and aims Minimal hepatic encephalopathy (MHE) may impair driving performance and adversely disturbs quality of life. Most drivers with chronic liver disease are not routinely screened for MHE and stay untreated due to the deficiency of standardization of normal values, simple tools, and skills to carry out tests. This study evaluated the usefulness of psychometric tests and critical flicker frequency (CFF) to diagnose MHE among screened drivers with chronic liver disease in Assiut, a city in Upper Egypt. Patients and methods A total of 100 drivers with chronic liver disease were screened for MHE. Routine investigations were carried out for all. Psychometric tests including number connection tests A, symbol digits test and CFF testing were applied for them. mini mental state examination questionnaires and Beck’s inventory were carried out for those diagnosed as having MHE. Results MHE was found among 40%, with 20 (50%) in Child’s A, 11 (27.5%) in Child’s B, and nine (22.5%) in Child’s C cirrhosis (P=0.027), and 45% of those with MHE had bad driving history. Twelve (12%) patients had abnormal psychometric tests. The sensitivity and specificity of receiver operating characteristic curves for CFF in the diagnosis of MHE was 100%, with a cutoff of less than or equal to 38.5 Hz, and the area under the curve was 1.00 (95% confidence interval, 0.964–1.00) (P<0.0001). There was significant reverse correlation between CFF and Child–Pugh score (r=−0.271, P=0.030). Conclusion Our data revealed a high prevalence of MHE (40%) among drivers with liver cirrhosis. The CFF test is a simple, accurate, and reliable test for diagnosis of MHE, with no age or literacy requirement. Therefore, we suggest to include the CFF test in screening of drivers with chronic liver disease for early discovery and proper management.

Keywords

• chronic liver disease
• critical flicker frequency
• minimal hepatic encephalopathy