Pathogenesis, diagnosis, and treatment of hepatic encephalopathy

Abstract

Hepatic encephalopathy (HE) is a neuropsychiatric disorder seen in patients with advanced liver disease or porto-systemic shunts. Based on etiology and severity of HE, the World Congress of Gastroenterology has divided HE into categories and sub-categories. Many user-friendly computer-based neuropsychiatric tests are being validated for diagnosing covert HE. Currently, emphasis is being given to view HE deficits as a continuous spectrum rather than distinct stages. Ammonia is believed to play crucial role in pathogenesis of HE via astrocyte swelling and cerebral edema. However, evidence has been building up which supports the synergistic role of oxidative stress, inflammation and neurosteroids in pathogenesis of HE. At present, treatment of HE aims at decreasing the production and intestinal absorption of ammonia. But as the role of new pathogenetic mechanisms becomes clear, many potential new treatment strategies may become available for clinician.

Keywords: AAA, aromatic amino acid; BAUR, brain ammonia utilization rate; BCAA, branched-chain amino acids; CFF, critical flicker fusion; DBI, diazepam binding inhibitor; DST, digit symbol test; DWI, diffusion weighted imaging; Diagnosis; ECAD, extra-corporeal albumin dialysis; EEC, electroencephalogram; FLAIR, fluid attenuation inversion recovery; HE, hepatic encephalopathy; HESA, hepatic encephalopathy scoring algorithm; ICT, inhibitory control test; IL, interleukin; LOLA, L-ornithine L-aspartate; LTT, line tracing test; MARS, molecular adsorbent reticulating system; MHE, minimal hepatic encephalopathy; MRI, magnetic resonance imaging; NAC, N-acetyl cysteine; NO, nitric oxide; NS, neurosteroids; NSAID, non-steroidal anti-inflammatory drugs; ODN, octadecaneuropeptide; OHE, overt hepatic encephalopathy; PTBR, peripheral-type benzodiaze-pine receptor; QOL, quality of life; SDT, serial dotting test; SEDACA, short epoch, dominant activity, and cluster analysis; SIBO, small intestinal bacterial overgrowth; SIRS, systemic inflammatory response syndrome; SOD, Superoxide dismutase; SONIC, spectrum of neurological impairment; TLP, TransLocator Protein; TNF, tumor necrosis factor; hepatic encephalopathy; pathogenesis; treatment.