Small Intestinal Bacterial Overgrowth Diagnosed by a Breath Test and Improved by Rifaximin in a Patient with Hepatic Encephalopathy and Alcoholic Liver Cirrhosis

Intern Med. 2020 Aug 1;59(15):1849-1853. doi: 10.2169/internalmedicine.4593-20. Epub 2020 Apr 23.


A 66-year-old Japanese man was admitted to our hospital with grade 2 hepatic encephalopathy (HE). Abdominal computed tomography and laboratory examinations revealed decompensated liver cirrhosis. Intravenous administration of branched-chain amino acids immediately ameliorated the HE, and lactulose was initiated. However, a breath test revealed small intestinal bacterial overgrowth (SIBO); therefore, rifaximin was additionally initiated. The breath test was repeated after discharge, when no evidence of SIBO or overt HE was identified. This case suggested that a breath test is effective for the identification of SIBO and that the administration of a poorly absorbed antibiotic should be considered in SIBO-positive HE patients taking lactulose.

Keywords: hepatic encephalopathy; liver cirrhosis; poorly absorbed antibiotics; small intestinal bacterial overgrowth.

Publication types

  • Case Reports

MeSH terms

  • Aged
  • Amino Acids, Branched-Chain / adverse effects*
  • Amino Acids, Branched-Chain / therapeutic use
  • Anti-Bacterial Agents / therapeutic use*
  • Blind Loop Syndrome / chemically induced
  • Blind Loop Syndrome / drug therapy*
  • Breath Tests / methods
  • Hepatic Encephalopathy / drug therapy*
  • Hepatic Encephalopathy / etiology
  • Humans
  • Lactulose / adverse effects*
  • Lactulose / therapeutic use
  • Liver Cirrhosis, Alcoholic / complications
  • Male
  • Rifaximin / therapeutic use*


  • Amino Acids, Branched-Chain
  • Anti-Bacterial Agents
  • Lactulose
  • Rifaximin